U.S. patent application number 15/192308 was filed with the patent office on 2017-08-10 for lighting fixture with enhanced security.
The applicant listed for this patent is Cree, Inc.. Invention is credited to John Barile, Keith Bryan, Matthew Deese.
Application Number | 20170230364 15/192308 |
Document ID | / |
Family ID | 59496366 |
Filed Date | 2017-08-10 |
United States Patent
Application |
20170230364 |
Kind Code |
A1 |
Barile; John ; et
al. |
August 10, 2017 |
LIGHTING FIXTURE WITH ENHANCED SECURITY
Abstract
A lighting fixture includes a solid-state light source,
communications circuitry, a memory, and processing circuitry. The
memory stores common security credentials, wherein the common
security credentials are pre-installed during a factory calibration
process. The processing circuitry is coupled to the solid-state
light source, the communications circuitry, and the memory. The
processing circuitry is configured to cause the solid-state light
source to provide a desired light output. Further, the processing
circuitry is configured to join a common network using the common
security credentials, wherein only devices with the common security
credentials are permitted to join the network.
Inventors: |
Barile; John; (Apex, NC)
; Bryan; Keith; (Raleigh, NC) ; Deese;
Matthew; (Raleigh, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cree, Inc. |
Durham |
NC |
US |
|
|
Family ID: |
59496366 |
Appl. No.: |
15/192308 |
Filed: |
June 24, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62292528 |
Feb 8, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21S 9/028 20130101;
G06K 9/4652 20130101; G06T 7/20 20130101; H05B 47/19 20200101; G06T
5/50 20130101; H05B 45/10 20200101; F21S 9/026 20130101; H02J 7/35
20130101; G06T 2207/20216 20130101; H05B 45/20 20200101; F21V 7/22
20130101; F21S 9/03 20130101; F21V 5/04 20130101; F21V 23/005
20130101; G06F 3/048 20130101; H05B 45/46 20200101; H05B 47/11
20200101; F21S 8/086 20130101; G06K 9/00979 20130101; H05B 47/18
20200101; G06K 9/6202 20130101; G06K 2009/00738 20130101; H05B
47/175 20200101; H05B 45/37 20200101; F21W 2131/103 20130101; G01S
13/08 20130101; H05B 47/105 20200101; G06K 9/4642 20130101; H04L
12/282 20130101; H05B 45/00 20200101; H05B 45/50 20200101; H04L
67/12 20130101; Y04S 40/18 20180501; H04L 63/0876 20130101; F21Y
2115/10 20160801; G01C 3/08 20130101; G01S 15/08 20130101; H02J
7/0068 20130101; H05B 47/16 20200101; F21Y 2103/10 20160801; G06K
9/00771 20130101; F21V 23/003 20130101 |
International
Class: |
H04L 29/06 20060101
H04L029/06; H05B 33/08 20060101 H05B033/08; G06K 9/00 20060101
G06K009/00; H05B 37/02 20060101 H05B037/02 |
Claims
1. A lighting fixture comprising: a solid-state light source;
communications circuitry; a memory storing common security
credentials, wherein the common security credentials are
pre-installed during a factory calibration process; and processing
circuitry coupled to the solid-state light source, the
communications circuitry, and the memory and configured to: cause
the solid-state light source to provide a desired light output; and
join a common network using the common security credentials,
wherein only devices with the common security credentials are
permitted to join the common network.
2. The lighting fixture of claim 1 wherein the processing circuitry
is further configured to: communicate with a device in the common
network via the communications circuitry; and receive updated
security credentials from the device via the communications
circuitry and store the updated security credentials in the
memory.
3. The lighting fixture of claim 2 wherein the processing circuitry
is further configured to use the updated security credentials to
communicate over the common network.
4. The lighting fixture of claim 3 wherein the processing circuitry
is further configured to forward the updated security credentials
to an additional device in the common network.
5. The lighting fixture of claim 4 wherein the common network and
the secure network are Thread networks.
6. The lighting fixture of claim 2 wherein the processing circuitry
is further configured to forward the updated security credentials
to an additional device in the common network.
7. The lighting fixture of claim 2 wherein the device authenticates
the lighting fixture to allow the lighting fixture to join the
common network.
8. The lighting fixture of claim 2 wherein the updated security
credentials are generated by the device.
9. The lighting fixture of claim 8 wherein the updated security
credentials are generated by the device based on user input to the
device.
10. The lighting fixture of claim 2 wherein the lighting fixture
and the device form a Thread network.
11. A lighting fixture comprising: a solid-state light source;
communications circuitry; a memory storing common security
credentials, wherein the common security credentials are
pre-installed during a factory calibration process; and processing
circuitry coupled to the solid-state light source, the
communications circuitry, and the memory and configured to: cause
the solid-state light source to provide a desired light output; and
create a common network using the common security credentials,
wherein only devices with the common security credentials are
permitted to join the common network.
12. The lighting fixture of claim 11 wherein creating the common
network comprises authenticating devices wishing to join the common
network based on the common security credentials.
13. The lighting fixture of claim 12 wherein creating the common
network further comprises assigning an address to the devices
wishing to join the common network that are authenticated based on
the common security credentials.
14. The lighting fixture of claim 12 wherein the processing
circuitry is configured to: receive a command to create the common
network from a device; and create the common network in response to
the command.
15. The lighting fixture of claim 14 wherein creating the common
network comprises authenticating the devices wishing to join the
common network based on the common security credentials.
16. The lighting fixture of claim 15 wherein creating the common
network further comprises assigning an address to the devices
wishing to join the common network that are authenticated based on
the common security credentials.
17. The lighting fixture of claim 14 wherein the command is
provided via the common network.
18. The lighting fixture of claim 14 wherein the command is not
provided via the common network.
19. The lighting fixture of claim 18 further comprising a light
sensor, wherein the command is provided via the light sensor.
20. The lighting fixture of claim 11 wherein the processing
circuitry is further configured to: communicate with a device in
the common network via the communications circuitry; receive
updated security credentials from the device via the communications
circuitry and store the updated security credentials in the memory;
and communicate with other devices in the common network using the
updated security credentials.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of provisional patent
application Ser. No. 62/292,528, filed Feb. 8, 2016, the disclosure
of which is hereby incorporated herein by reference in its
entirety.
FIELD OF THE DISCLOSURE
[0002] The present disclosure relates to lighting fixtures, and in
particular to lighting fixtures with enhanced security.
BACKGROUND
[0003] Lighting fixtures continue to evolve, incorporating features
such as sensors, processing circuitry, networking circuitry, and
the like. Accordingly, lighting fixtures may implement lighting
programs, respond to the surrounding environment, and be
controlled, for example, over a local area network and/or the
Internet.
[0004] Thus far, lighting fixtures have been primarily concerned
with measuring environmental factors directly related to the light
output thereof (e.g., ambient light and occupancy). These
environmental factors have generally been used to make decisions
locally, for example, regarding the light output level of the
lighting fixture to which the sensors are attached.
[0005] Networking circuitry has been incorporated into many
lighting fixtures to allow them to communicate with one another.
For example, a common approach is to form a mesh network of
lighting fixtures in which the lighting fixtures can communicate
with one another and/or receive commands from remote devices.
Generally, these lighting fixture networks are used to provide
control commands to various lighting fixtures or groups of lighting
fixtures to adjust the light output thereof in some manner.
[0006] While the above mentioned features may improve the utility
of a lighting fixture or group of lighting fixtures, there are
significant opportunities for improvement.
SUMMARY
[0007] The present disclosure relates to lighting fixtures, and in
particular to lighting fixtures with enhanced security. In one
embodiment, a lighting fixture includes a solid-state light source,
communications circuitry, a memory, and processing circuitry. The
memory stores common security credentials, wherein the common
security credentials are pre-installed during a factory calibration
process. The processing circuitry is coupled to the solid-state
light source, the communications circuitry, and the memory. The
processing circuitry is configured to cause the solid-state light
source to provide a desired light output. Further, the processing
circuitry is configured to join a common network using the common
security credentials, wherein only devices with the common security
credentials are permitted to join the network. By using the common
security credentials to join the network, a large number of
lighting fixtures and other devices may form a secure distributed
lighting network without manual intervention from a user. The
common security credentials may then be updated to secure the
network.
[0008] In one embodiment, the processing circuitry is further
configured to communicate with a device in the common network via
the communications circuitry and receive updated security
credentials from the device and store them in the memory. The
processing circuitry may then use the updated security credentials
to communicate over the common network.
[0009] In one embodiment, a lighting fixture includes a solid-state
light source, communications circuitry, a memory, and processing
circuitry. The memory stores common security credentials, wherein
the common security credentials are pre-installed during a factory
calibration process. The processing circuitry is coupled to the
solid-state light source, the communications circuitry, and the
memory. The processing circuitry is configured to cause the
solid-state light source to provide a desired light output.
Further, the processing circuitry is configured to create a common
network using the common security credentials, wherein only devices
with the common security credentials are permitted to join the
network. By using the common security credentials to create the
network, a large number of lighting fixtures and other devices may
form a secure distributed lighting network without manual
intervention from a user. The common security credentials may then
be updated to secure the network.
[0010] Those skilled in the art will appreciate the scope of the
present disclosure and realize additional aspects thereof after
reading the following detailed description of the preferred
embodiments in association with the accompanying drawing
figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0011] The accompanying drawing figures incorporated in and forming
a part of this specification illustrate several aspects of the
disclosure, and together with the description serve to explain the
principles of the disclosure.
[0012] FIG. 1 is a block diagram of a distributed lighting network
according to one embodiment of the present disclosure.
[0013] FIG. 2 is a functional schematic of a lighting fixture
according to one embodiment of the present disclosure.
[0014] FIG. 3 is a functional schematic of a sensor module
according to one embodiment of the present disclosure.
[0015] FIG. 4 is a functional schematic of a lighting fixture
connected to a sensor module according to one embodiment of the
present disclosure.
[0016] FIG. 5 is a functional schematic of a controller according
to one embodiment of the present disclosure.
[0017] FIG. 6 is a functional schematic of a controller connected
to a sensor module according to one embodiment of the present
disclosure.
[0018] FIG. 7 is a functional schematic of a border router
according to one embodiment of the present disclosure.
[0019] FIG. 8 is a functional schematic of a border router
connected to a sensor module according to one embodiment of the
present disclosure.
[0020] FIG. 9 is a diagram illustrating a distributed lighting
system according to one embodiment of the present disclosure.
[0021] FIG. 10 is a call flow diagram illustrating a process for
automatically grouping a number of devices in a distributed
lighting network according to one embodiment of the present
disclosure.
[0022] FIG. 11 is a table indicating a detected link strength
between lighting fixtures in a distributed lighting network.
[0023] FIG. 12 is a table indicating a neighbor ranking for each
one of a number of lighting fixtures in a distributed lighting
network.
[0024] FIG. 13 is a flow diagram illustrating a process for adding
devices to a distributed lighting network according to one
embodiment of the present disclosure.
[0025] FIG. 14 is a diagram illustrating a distributed lighting
system according to one embodiment of the present disclosure.
[0026] FIG. 15 is a flow diagram illustrating a process for
grouping devices in a distributed lighting network according to one
embodiment of the present disclosure.
[0027] FIG. 16 is a flow diagram illustrating a process for factory
calibration of the lighting fixture according to one embodiment of
the present disclosure.
[0028] FIG. 17 is a flow diagram illustrating a process for
operating a lighting fixture or other device to create a secure
distributed lighting network according to one embodiment of the
present disclosure.
[0029] FIG. 18 is a call flow diagram illustrating a process for
creating a secure distributed lighting network according to one
embodiment of the present disclosure.
[0030] FIG. 19 is a flow diagram illustrating a process for
operating a lighting fixture or other device to create a secure
distributed lighting network according to one embodiment of the
present disclosure.
[0031] FIG. 20 is a call flow diagram illustrating a process for
creating a secure distributed lighting network according to one
embodiment of the present disclosure.
[0032] FIG. 21 is a flow diagram illustrating a process for
operating a lighting fixture or other device to create a secure
distributed lighting network according to one embodiment of the
present disclosure.
[0033] FIG. 22 is a call flow diagram illustrating a process for
creating a secure distributed lighting network according to one
embodiment of the present disclosure.
[0034] FIG. 23 is a flow diagram illustrating a process operating a
lighting fixture or other device for updating security credentials
in a distributed lighting network according to one embodiment of
the present disclosure.
[0035] FIG. 24 is a call flow diagram illustrating a process for
updating security credentials in a distributed lighting network
according to one embodiment of the present disclosure.
[0036] FIGS. 25A through 25C are diagrams illustrating a
distributed lighting network according to various embodiment of the
present disclosure.
[0037] FIG. 26 is a call flow diagram illustrating a process for
adjusting the light output of one or more lighting fixtures in a
distributed lighting network according to one embodiment of the
present disclosure.
[0038] FIGS. 27A through 27D are diagrams illustrating a
distributed lighting network according to various embodiments of
the present disclosure.
[0039] FIG. 28 is a flow diagram illustrating a process for
detecting devices near entrances and/or exits according to one
embodiment of the present disclosure.
[0040] FIG. 29 is a flow diagram illustrating a process for
determining and indicating a desired position of a border router in
a distributed lighting network according to one embodiment of the
present disclosure.
[0041] FIG. 30 is a flow diagram illustrating a process for
calibrating one or more ambient light sensors according to one
embodiment of the present disclosure.
[0042] FIG. 31 is a call flow diagram illustrating a process for
determining and using an optimal communication channel in a
distributed lighting network according to one embodiment of the
present disclosure.
[0043] FIG. 32 is a call flow diagram illustrating a process for
determining and using an optimal communication channel in a
distributed lighting network according to one embodiment of the
present disclosure.
[0044] FIGS. 33A and 33B are flow diagrams illustrating a process
for detecting occupancy using an image sensor according to one
embodiment of the present disclosure.
[0045] FIG. 34 is a flow diagram illustrating a process for
adjusting a light level of a lighting fixture in order to properly
detect occupancy in a lighting fixture according to one embodiment
of the present disclosure.
[0046] FIG. 35 is a functional schematic of power converter
circuitry according to one embodiment of the present
disclosure.
[0047] FIG. 36 is a flow diagram illustrating a process for
detecting and responding to a commissioning tool using an image
sensor according to one embodiment of the present disclosure.
[0048] FIG. 37 is a flow diagram illustrating a process for
providing merged images from multiple image sensors in a
distributed lighting network according to one embodiment of the
present disclosure.
[0049] FIG. 38 is a flow diagram illustrating a process for
correlating image data and geospatial data and displaying the
result according to one embodiment of the present disclosure.
[0050] FIG. 39 is a flow diagram illustrating a process for
adjusting a drive signal to a light source in order to reduce the
energy consumption of a lighting fixture according to one
embodiment of the present disclosure.
[0051] FIG. 40 is a diagram illustrating a process for adjusting a
drive signal to a light source in order to reduce the energy
consumption of a lighting fixture according to one embodiment of
the present disclosure.
[0052] FIG. 41 is a flow diagram illustrating a process for
measuring and determining the power consumption of a device in a
distributed lighting network according to one embodiment of the
present disclosure.
[0053] FIG. 42 is a flow diagram illustrating a process for
reducing the power consumption of a device in a distributed
lighting network according to one embodiment of the present
disclosure.
[0054] FIGS. 43A and 43B illustrate a lighting fixture according to
one embodiment of the present disclosure.
[0055] FIG. 44 is a functional schematic of a lighting fixture
according to one embodiment of the present disclosure.
[0056] FIG. 45 is a functional schematic of a lighting fixture
connected to a sensor module according to one embodiment of the
present disclosure.
[0057] FIG. 46 illustrates a lighting fixture according to one
embodiment of the present disclosure.
[0058] FIG. 47 is a flow diagram illustrating a process for
detecting an optical indicator and adjusting settings based on the
optical indicator according to one embodiment of the present
disclosure.
[0059] FIG. 48 is a flow diagram illustrating a process for
determining one or more environmental conditions based on sensor
data measured by devices in a distributed lighting network
according to one embodiment of the present disclosure.
[0060] FIG. 49 is a flow diagram illustrating a process for
adjusting one or more building management system (BMS) parameters
based on sensor data measured by devices in a distributed lighting
network according to one embodiment of the present disclosure.
[0061] FIG. 50 is a call flow diagram illustrating a process for
communication between devices in a distributed lighting network
according to one embodiment of the present disclosure.
[0062] FIG. 51 is a call flow diagram illustrating a process for
communication between a remote device and the devices in a
distributed lighting network according to one embodiment of the
present disclosure.
[0063] FIG. 52 is a flow diagram illustrating a process for
transferring settings between devices in a distributed lighting
network according to one embodiment of the present disclosure.
[0064] FIGS. 53A and 53B illustrate a lighting fixture according to
one embodiment of the present disclosure.
DETAILED DESCRIPTION
[0065] The embodiments set forth below represent the necessary
information to enable those skilled in the art to practice the
embodiments and illustrate the best mode of practicing the
embodiments. Upon reading the following description in light of the
accompanying drawing figures, those skilled in the art will
understand the concepts of the disclosure and will recognize
applications of these concepts not particularly addressed herein.
It should be understood that these concepts and applications fall
within the scope of the disclosure and the accompanying claims.
[0066] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element, without departing from the
scope of the present disclosure. As used herein, the term "and/or"
includes any and all combinations of one or more of the associated
listed items.
[0067] It will be understood that when an element such as a layer,
region, or substrate is referred to as being "on" or extending
"onto" another element, it can be directly on or extend directly
onto the other element or intervening elements may also be present.
In contrast, when an element is referred to as being "directly on"
or extending "directly onto" another element, there are no
intervening elements present. Likewise, it will be understood that
when an element such as a layer, region, or substrate is referred
to as being "over" or extending "over" another element, it can be
directly over or extend directly over the other element or
intervening elements may also be present. In contrast, when an
element is referred to as being "directly over" or extending
"directly over" another element, there are no intervening elements
present. It will also be understood that when an element is
referred to as being "connected" or "coupled" to another element,
it can be directly connected or coupled to the other element or
intervening elements may be present. In contrast, when an element
is referred to as being "directly connected" or "directly coupled"
to another element, there are no intervening elements present.
[0068] Relative terms such as "below" or "above" or "upper" or
"lower" or "horizontal" or "vertical" may be used herein to
describe a relationship of one element, layer, or region to another
element, layer, or region as illustrated in the Figures. It will be
understood that these terms and those discussed above are intended
to encompass different orientations of the device in addition to
the orientation depicted in the Figures.
[0069] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. As used herein, the singular forms "a," "an," and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises," "comprising," "includes," and/or
"including" when used herein specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0070] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
disclosure belongs. It will be further understood that terms used
herein should be interpreted as having a meaning that is consistent
with their meaning in the context of this specification and the
relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0071] FIG. 1 illustrates a distributed lighting network 10
according to one embodiment of the present disclosure. The
distributed lighting network 10 includes a number of lighting
networks 12, and in particular a wireless lighting network 12A and
a wired lighting network 12B. The wireless lighting network 12A
includes a number of devices 14, which may be lighting fixtures
14A, sensor modules 14B, controllers 14C, and border routers 14D.
The devices 14 communicate with one another via wireless signals.
In one embodiment, the devices 14 form a wireless mesh network,
such that communication between two endpoints may be accomplished
via one or more hops. For example, the devices 14 may communicate
with one another via Institute of Electrical and Electronics
Engineers (IEEE) standard 802.15 or some variant thereof. Using a
wireless mesh network to communicate among the devices 14 may
increase the reliability thereof and allow the wireless lighting
network 12A to span large areas.
[0072] The wired lighting network 12B also includes a number of
devices 14. In addition to including lighting fixtures 14A, sensor
modules 14B, controllers 14C, and border routers 14D, the wired
lighting network 12B may also include one or more switches 14E. In
contrast to the wireless lighting network 12A, the devices 14 in
the wired lighting network 12B communicate with one another via
signals sent over a wired interface. In particular, the devices 14
may communicate with one another via an Ethernet interface, which
is facilitated by a switch 14E. There may be multiple switches 14E
in the wired lighting network 12B, each of which is connected to a
particular subset of the devices 14. In one embodiment, the
switches 14E are Power over Ethernet (PoE) switches such as those
conforming to IEEE standard 802.3. Accordingly, the switches 14E
may provide power to the devices 14 while simultaneously
facilitating the exchange of data between the devices 14. While
each one of the devices 14 are shown individually connected to a
switch 14E, the devices 14 may be connected to one another in any
manner, such that one of the devices 14 connects to one or more of
the switches 14E via one or more other devices 14.
[0073] Each border router 14D may be in communication with each
other border router 14D, or a subset of each other border router
14D. Such communication may occur in a wired or wireless manner.
Similarly, each switch 14E may be in communication with each other
switch 14E, or a subset of each other switch 14E. At least one of
the switches 14E is in communication with at least one of the
border routers 14D. The one or more border routers 14D in
communication with the one or more switches 14E act as a bridge
between the wireless lighting network 12A and the wired lighting
network 12B, and therefore allow the separate networks to
communicate with one another. Such bridge functionality may involve
network address translation, network protocol translation, and the
like, which is facilitated by the border router 14D. While the
border router 14D in FIG. 1 is shown bridging the wireless lighting
network 12A and the wired lighting network 12B, the border router
14D may also bridge two or more separate wireless lighting networks
12A, two or more wired lighting networks 12B, or any combination
thereof. Further, while multiple border routers 14D are shown in
FIG. 1, only a single border router 14D may be provided in some
embodiments. Generally, additional border routers 14D are provided
to increase network reliability and speed. Similarly, while
multiple switches 14E are shown in FIG. 1, only one switch 14E may
be provided in some embodiments. Generally, additional switches 14E
are provided to support a larger number of devices 14, since the
capacity of each switch 14E is limited. In one embodiment, the
functionality of the border router 14D and the switch 14E is
combined, such that each device 14 in the wired lighting network
12B connects directly or indirectly to one of the border routers
14D (rather than connecting to one of the border routers 14D via a
switch 14E).
[0074] In addition to bridging the wireless lighting network 12A
and the wired lighting network 12B, one or more of the border
routers 14D may also connect to other communications networks such
as the Internet. Further, one or more of the border routers 14D may
interface, either directly or indirectly, with one or more remote
devices 16 (e.g., a computer or wireless communications device).
When communicating directly with the one or more border routers
14D, the one or more remote devices 16 may do so in a wired or
wireless fashion, and in any number of communications
standards/protocols. When communicating indirectly with the one or
more border routers 14D, the one or more remote devices 16 may do
so via an access point 18 connected to the Internet, which is in
turn connected to the one or more border routers 14D. Once again,
the one or more border routers 14D are responsible for translating
the various network addresses, protocols, and the like between the
different devices.
[0075] In addition to the bridge functionality discussed above, one
or more of the border routers 14D may also communicate with a
building management system 20, such as those conventionally used to
control HVAC, security, and other building systems. Accordingly,
one or more of the border routers 14D may include specialty
communications circuitry for communicating with the building
management system 20 in a wired or wireless manner. In another
embodiment, the building management system 20 is fitted with a
communication module (not shown) which enables wired or wireless
communications with one or more of the border routers 14D. Allowing
one or more of the border routers 14D to communicate with the
building management system 20 may add significant intelligence to
an existing building management system 20, and may allow for
detailed insights regarding a space as well as energy and cost
savings as discussed below.
[0076] The wireless and wired communications in the distributed
lighting network 10 may occur in any number of communications
standards/protocols. Additionally, the number of devices 14, border
routers 14D, switches 14E, remote devices 16, and the like may be
different in various embodiments. Using one or more of the border
routers 14D to bridge the wireless lighting network 12A and the
wired lighting network 12B extends the reach of the distributed
lighting network 10, which may increase the functionality thereof.
Further, using one or more of the border routers 14D to provide a
bridge to other networks and devices may significantly increase the
functionality thereof as discussed below.
[0077] The devices 14 may use the distributed lighting network 10
to communicate with one another. For example, the devices 14 may
exchange status information, sensor data, commands, and the like.
Messages passed between the devices 14 may be individually
addressed such that the messages are received by a single one of
the devices 14, broadcast to a subset of the devices 14, or
broadcast to all of the devices 14. The border routers 14D and/or
switches 14E may collect and store information from the devices 14.
For example, the border routers 14D may collect and store status
information, sensor data, or the like from the devices 14. Further,
the border routers 14D and/or switches 14E may relay commands from
the remote devices 16 to one or more of the devices 14, and may
facilitate the collection of data from the devices 14 by the remote
devices 16, either by providing cached data located in local
storage in the border routers 14D or by requesting the data
directly from the devices 14. At least one border router 14D or a
designated device in communication with at least one border router
14D may provide an Application Program Interface (API), which is
made available to devices connected to the distributed lighting
network 10. In one embodiment, relevant information regarding the
functioning of each one of the devices 14 (e.g., status
information, sensor data, and the like) is locally cached for a
period of time within each individual device. It may then be
periodically retrieved and stored by one or more of the border
routers 14D, or may be retrieved by one or more of the border
routers 14D in response to a request from one or more of the remote
devices 16. Each one of the devices 14 may also periodically
broadcast relevant operational information, which is received and
stored by one or more of the border routers 14D. Alternatively,
operational information regarding each one of the devices 14 is not
cached, but real time operational information can be obtained when
requested. Virtually endless configurations exist for the storage
and retrieval of information among the various components of the
distributed lighting network 10, all of which are contemplated
herein.
[0078] Notably, each one of the devices 14 is capable of operating
independently of the others, and thus does not need to connect to
the distributed lighting network 10 to function. For example, each
one of the devices 14 may be capable of detecting the occurrence of
an occupancy event and responding thereto (by adjusting the light
output thereof in the case of a lighting fixture 14A), detecting
changes in an ambient light level of the space surrounding the
device and responding thereto (by adjusting the light output
thereof in the case of a lighting fixture 14A). In other words, the
control logic for each one of the devices 14 is locally stored and
executed, and does not require external input. When connected to
the distributed lighting network 10, the control logic of each one
of the devices 14 may consider information provided via the
distributed lighting network 10, and therefore the behavior of each
one of the devices 14 may be influenced by other devices 14 in the
network and/or one or more of the remote devices 16. For example,
upon detection of an occupancy event by one of the devices 14,
other devices 14 may respond to the detected occupancy event.
[0079] Similar to the above, a group of devices 14 may function
together (e.g., sharing information and communicating with one
another) without connecting to a border router 14D. In other words,
the border router(s) 14D do not directly facilitate communication
between the devices 14. This is due to the local control of each
device discussed above. Accordingly, a border router 14D may or may
not be provided, or may become disconnected or otherwise
non-operational without causing a failure of the devices 14. While
the additional functionality of the border router 14D may be lost
(e.g., as a network bridge between other networks), the devices 14
may still benefit from communicating with one another and enjoy the
functionality afforded by such communication.
[0080] FIG. 2 is a block diagram illustrating details of a lighting
fixture 14A according to one embodiment of the present disclosure.
The lighting fixture 14A includes driver circuitry 22 and an array
of light emitting diodes (LEDs) 24. The driver circuitry 22
includes power converter circuitry 26, communications circuitry 28,
processing circuitry 30, a memory 32, and sensor circuitry 34. The
power converter circuitry 26 is configured to receive an
alternating current (AC) or direct current (DC) input signal
(V.sub.IN) and perform power conversion to provide a regulated
output power to the array of LEDs 24. Notably, the power converter
circuitry 26 may be configured such that the input signal
(V.sub.IN) is provided in whole or in part by a battery, such that
the lighting fixture 14A is portable, capable of operating in
emergencies such as power outages, and/or capable of being used in
one or more off-grid applications as discussed below. In one
embodiment, the power converter circuitry 26 is configured to
provide a pulse-width modulated (PWM) regulated output signal to
the array of LEDs 24. While not shown, a connection between the
power converter circuitry 26 and each one of the communications
circuitry 28, the processing circuitry 30, the memory 32, and the
sensor circuitry 34 may provide regulated power to these portions
of the driver circuitry 22 as well. The processing circuitry 30 may
provide the main intelligence of the lighting fixture 14A, and may
execute instructions stored in the memory 32 in order to do so. The
processing circuitry 30 may thus control the amount of current,
voltage, or both provided from the power converter circuitry 26 to
the array of LEDs 24. The communications circuitry 28 may enable
the lighting fixture 14A to communicate via wireless or wired
signals to one or more other lighting fixtures 14A, sensor modules
14B, controllers 14C, border routers 14D, switches 14E, or any
other devices. The communications circuitry 28 may be coupled to
the processing circuitry 30 such that information received via the
communications circuitry 28 can be considered and acted upon by the
processing circuitry 30. The sensor circuitry 34 may include any
number of different sensors 36. For example, the sensor circuitry
34 may include one or more passive infrared (PIR) occupancy
sensors, one or more ambient light sensors, one or more
microphones, one or more speakers, one or more ultrasonic sensors
and/or transducers, one or more infrared receivers, one or more
imaging sensors such as a camera, a multi-spectral imaging sensor,
or the like, one or more atmospheric pressure sensors, one or more
temperature and/or humidity sensors, one or more air quality
sensors such as oxygen sensors, carbon dioxide sensors, volatile
organic compound (VOC) sensors, smoke detectors, and the like, one
or more positioning sensors such as accelerometers, Global
Positioning Satellite (GPS) sensors, and the like, one or more
magnetic field sensors, or any other sensors. The sensor circuitry
34 may be in communication with the processing circuitry 30 such
that information from the sensors 36 can be considered and acted
upon by the processing circuitry 30. In some situations, the
processing circuitry 30 may use information from the sensors 36 to
adjust the voltage and/or current provided from the power converter
circuitry 26 to the array of LEDs 24, thereby changing one or more
aspects of the light provided by the lighting fixture 14A. In other
situations, the processing circuitry 30 may communicate information
from the sensors 36 via the communications circuitry 28 to one or
more of the devices 14 or one or more of the border routers 14D in
the distributed lighting network 10, or to one or more of the
remote devices 16. In still other situations, the lighting fixture
14A may both change one or more aspects of the light provided
therefrom based on information from the one or more sensors 36 and
communicate the information from the one or more sensors 36 via the
communications circuitry 28.
[0081] The array of LEDs 24 includes multiple LED strings 38. Each
LED string 38 includes a number of LEDs 40 arranged in series
between the power converter circuitry 26 and ground. Notably, the
disclosure is not limited to lighting fixtures 14A having LEDs 40
arranged in this manner. The LEDs 40 may be arranged in any
series/parallel combination, may be coupled between contacts of the
power converter circuitry 26, or arranged in any other suitable
configuration without departing from the principles described
herein. The LEDs 40 in each one of the LED strings 38 may be
fabricated from different materials and coated with different
phosphors such that the LEDs 40 are configured to provide light
having different characteristics than the LEDs 40 in each other LED
string 38. For example, the LEDs 40 in a first one of the LED
strings 38 may be manufactured such that the light emitted
therefrom is green, and include a phosphor configured to shift this
green light into blue light. Such LEDs 40 may be referred to as
blue-shifted green (BSG) LEDs. The LEDs 40 in a second one of the
LED strings 38 may be manufactured such that the light emitted
therefrom is blue, and include a phosphor configured to shift this
blue light into yellow light. Such LEDs 40 may be referred to as
blue-shifted yellow (BSY) LEDs. The LEDs 40 in a third one of the
LED strings 38 may be manufactured to emit red light, and may be
referred to as red (R) LEDs. The light output from each LED string
38 may combine to provide light having a desired hue, saturation,
brightness, etc. Any different types of LEDs 40 may be provided in
each one of the LED strings 38 to achieve any desired light output.
The power converter circuitry 26 may be capable of individually
changing the voltage and/or current provided through each LED
string 38 such that the hue, saturation, brightness, or any other
characteristic of the light provided from the array of LEDs 40 can
be adjusted.
[0082] The lighting fixture 14A may be an indoor lighting fixture
or an outdoor lighting fixture. Accordingly, the distributed
lighting network 10 may include any number of both indoor and
outdoor lighting fixtures.
[0083] FIG. 3 is a block diagram illustrating details of a sensor
module 14B according to one embodiment of the present disclosure.
The sensor module 14B includes power converter circuitry 42,
communications circuitry 44, processing circuitry 46, a memory 48,
sensor circuitry 50, and an indicator light LED_I. The power
converter circuitry 42 is configured to receive an AC or DC input
signal (V.sub.IN) and perform power conversion to provide a
regulated output power to one or more of the communications
circuitry 44, the processing circuitry 46, the memory 48, and the
sensor circuitry 50. Notably, the power converter circuitry 42 may
be configured such that the input signal (V.sub.IN) may be provided
at least in part by a battery, such that the sensor module 14B is
portable, suitable for one or more off-grid applications, and/or
capable of operating in emergencies such as power outages. The
processing circuitry 30 may provide the main intelligence of the
sensor module 14B, and may execute instructions stored in the
memory 48 to do so. The communications circuitry 44 may enable the
sensor module 14B to communicate via wireless or wired signals to
one or more other lighting fixtures 14A, sensor modules 14B,
controllers 14C, border routers 14D, switches 14E, or other
devices. In some embodiments, regulated power is received at the
communications circuitry 44 (e.g., via a communications interface
providing both power and data such as an Inter-Integrated Circuit
(I.sup.2C) bus, a universal serial bus (USB), or PoE), where it is
then distributed to the processing circuitry 46, the memory 48, and
the sensor circuitry 50. Accordingly, in some embodiments, the
power converter circuitry 42 may not be provided in the sensor
module 14B. The communications circuitry 44 may be coupled to the
processing circuitry 46 such that information received via the
communications circuitry 44 may be considered and acted upon by the
processing circuitry 46. The sensor circuitry 50 may include any
number of sensors 52 as discussed above. The sensor circuitry 50
may be in communication with the processing circuitry 46 such that
information from the sensors 52 can be considered and acted upon by
the processing circuitry 46. The indicator light LED_I may provide
status information to a user, for example, by changing the
intensity, color, blinking frequency, or the like. Further, the
indicator light LED_I may be used to participate in an automatic
grouping process as discussed below.
[0084] It may be desirable to incorporate the sensor modules 14B
into the distributed lighting network 10 in order to fill gaps in
sensor coverage from the sensors 36 in the lighting fixtures 14A.
That is, the spacing between lighting fixtures 14A may leave gaps
in sensor coverage, which may be filled by standalone sensor
modules 14B. Additionally, the sensor modules 14B provide the
ability to include sensors in locations in which lighting fixtures
are not provided, or where legacy lighting fixtures (e.g.,
incandescent or fluorescent lighting fixtures are provided
instead). Further, the flexibility of the sensor modules 14B may
allow them to be incorporated into pre-existing devices including
access to power, such as legacy lighting fixtures, exit signs,
emergency lighting arrays, and the like. Finally, since the sensor
modules 14B do not include the LED array 24, they may be
significantly less expensive to manufacture, and therefore may
allow sensors to be deployed throughout a space at a reduced
cost.
[0085] FIG. 4 is a block diagram illustrating details of a lighting
fixture 14A according to an additional embodiment of the present
disclosure. The lighting fixture 14A shown in FIG. 4 is similar to
that shown in FIG. 2, except that the sensor circuitry 34 is
removed from the driver circuitry 22. In place of the sensor
circuitry 34, the driver circuitry 22 connects to a sensor module
14B, which is integrated into the lighting fixture 14A. The sensor
module 14B is substantially similar to that shown above in FIG. 3,
but does not include the power converter circuitry 42, since, in
the current embodiment, power is supplied to the sensor module 14B
via the communications circuitry 44 (e.g., via an I.sup.2C, USB, or
PoE interface). However, the disclosure is not so limited. The
driver circuitry 22 may maintain all or a portion of the sensors 36
shown in FIG. 2 and the sensor module 14B may maintain the power
converter circuitry 42 in some embodiments. Further, the sensor
module 14B may share one or more components with the driver
circuitry 22 in various embodiments. The sensor module 14B may be
detachable from the lighting fixture 14A and thus upgradeable over
time. Details of such an upgradeable lighting fixture 14A are
described in co-pending U.S. patent application Ser. No.
14/874,099, the contents of which are hereby incorporated by
reference in their entirety. As discussed in this application, the
sensor module 14B may connect to the driver circuitry 22 via a
connector in the lighting fixture 14A, and may aesthetically blend
with the appearance of the lighting fixture 14A when installed.
[0086] Connecting a sensor module 14B to a lighting fixture 14A in
this manner provides several benefits. First and foremost, it is a
modular approach, and thus foregoes the need for separate product
lines with and without the additional functionality of the sensor
module 14B. Second, the sensor module 14B may be upgradeable
without changing the lighting fixture 14A, for example, to add
additional sensors and functionality to the lighting fixture 14A.
Third, the sensor module 14B may include separate processing
circuitry 46 from the lighting fixture 14A. Since the processing
power of the processing circuitry 30 may be limited, and since it
is desirable to avoid overloading and thus slowing the
functionality of the processing circuitry 30 in the lighting
fixture 14A, having separate processing circuitry 46 for
conditioning or otherwise operating on data from the sensors 52 in
the sensor module 14B may be highly advantageous. In general, any
number of sensors may be directly integrated with a lighting
fixture 14A, separate from the lighting fixture 14A and connected
in either a wired or wireless manner thereto, or separate from the
lighting fixture 14A and connected via a network interface to the
lighting fixture 14A.
[0087] FIG. 5 is a block diagram illustrating details of a
controller 14C according to one embodiment of the present
disclosure. The controller 14C is similar to the lighting fixtures
14A and sensor module 14B discussed above, and includes power
converter circuitry 54, communications circuitry 56, processing
circuitry 58, a memory 60, sensor circuitry 62 with a number of
sensors 64, and an indicator light LED_I. The function of each of
these components is similar to that discussed above for the
lighting fixtures 14A and sensor module 14B. The controller 14C
further includes a user interface 66 that allows for interaction
with the controller. The user interface 66 may include one or more
physical buttons, switches, dials, etc., or may include a software
interface that is displayed on a screen or touch-enabled screen.
The user interface 66 is coupled to the processing circuitry 58
such that input provided via the user interface 66 can be
considered and acted upon by the processing circuitry 58. In one
embodiment, the controller 14C is a wall-mounted switch that
includes one or more paddles that act as the user interface 66. For
example, the controller 14C may be a CWD-CWC-XX and/or CWS-CWC-XX
wall controller manufactured by Cree, Inc. of Durham, N.C. Similar
to the sensor module 14B discussed above, the controller 14C may
also be configured to be powered at least in part by a battery such
that the controller is portable, suitable for one or more off-grid
applications, and/or capable of operating in emergencies such as
power outages.
[0088] FIG. 6 is a block diagram illustrating details of a
controller 14C according to an additional embodiment of the present
disclosure. The controller 14C shown in FIG. 6 is similar to that
shown in FIG. 5, except that the sensor circuitry 62 is removed. In
place of the sensor circuitry 62, the controller 14C connects to a
sensor module 14B, which is integrated into the controller 14C. The
sensor module 14B is substantially similar to that shown above in
FIG. 3, but does not include the power converter circuitry 42,
since, in the current embodiment, power is supplied to the sensor
module 14B via the communications circuitry 44 (e.g., via an
I.sup.2C, USB, or PoE interface). However, the disclosure is not so
limited. The controller 14C may maintain all or a portion of the
sensors 64 shown in FIG. 5 and the sensor module 14B may maintain
the power converter circuitry 42 in some embodiments. Further, the
sensor module 14B may share one or more components with the
controller 14C in various embodiments. The sensor module 14B may be
detachable from the controller 14C and thus upgradeable over time.
As discussed above, providing the sensor module 14B in this manner
may forego the need for additional product lines, maintain
upgradeability of the controller without changing the core hardware
thereof, and provide additional processing resources.
[0089] FIG. 7 is a block diagram illustrating details of a border
router 14D according to one embodiment of the present disclosure.
The border router 14D includes power converter circuitry 68,
communications circuitry 70, processing circuitry 72, a memory 74,
sensor circuitry 76, and an indicator light LED_I. As discussed
above, the power converter circuitry 68 may receive an AC or DC
input signal (V.sub.IN) and perform power conversion to provide a
converted output signal, which is used to power the communications
circuitry 70, the processing circuitry 72, the memory 74, and the
sensor circuitry 76. The input signal (V.sub.IN) may be provided in
whole or in part by a battery in some embodiments, such that the
border router 14D is portable, suitable for one or more off-grid
applications, and/or capable of operating in emergencies such as
power outages. The communications circuitry 70 allows the border
router 14D to communicate with lighting fixtures 14A, sensor
modules 14B, controllers 14C, switches 14E, remote devices 16, and
the like, and allows the border router 14D to bridge the various
networks discussed above with respect to FIG. 1. Accordingly, the
communications circuitry 70 in the border router 14D may be more
robust than the communications circuitry in the lighting fixtures
14A, sensor modules 14B, controllers 14C, switches 14E, and remote
devices 16. In particular, while the lighting fixtures 14A, sensor
modules 14B, controllers 14C, switches 14E, and remote devices 16
may communicate via a single communications protocol or a handful
of communications protocols and thus include communications
circuitry configured only to communicate in this manner, the
communications circuitry 70 of the border router may support
communication in a large number of diverse communications protocols
such that the border router 14D is capable of bridging these
various networks. The processing circuitry 72 provides the central
intelligence of the border router 14D, and may execute instructions
stored in the memory 74 in order to do so. For example, the
processing circuitry 72 may facilitate the collection and storage
of operational data from the lighting fixtures 14A, sensor modules
14B, and controllers 14C, and further may facilitate the API
discussed above to allow remote devices 16 to obtain said
operational information. The sensor circuitry 76 may include any
number of sensors 78 such as those discussed above, so that the
border router 14D may collect information from its own sensors 78
in addition to those provided by the lighting fixtures 14A, sensor
modules 14B, and controllers 14C.
[0090] FIG. 8 is a block diagram illustrating details of a border
router 14D according to an additional embodiment of the present
disclosure. The border router 14D is substantially similar to that
shown above in FIG. 7, except that the sensor circuitry 76 is
removed from the border router 14D. In place of the sensor
circuitry 76, the border router 14D connects to a sensor module
14B, which is integrated into the border router 14D. The sensor
module 14B is substantially similar to that shown above in FIG. 3,
but does not include the power converter circuitry 42, since, in
the current embodiment, power is supplied to the sensor module 14B
via the communications circuitry 44 (e.g., via an I.sup.2C or PoE
interface). However, the disclosure is not so limited. The border
router 14D may maintain all or a portion of the sensors 78 shown in
FIG. 7 and the sensor module 14B may maintain the power converter
circuitry 42 in some embodiments. Further, the sensor module 14B
may share one or more components with the border router 14D in
various embodiments. The sensor module 14B may be detachable from
the border router 14D and upgradeable over time. As discussed
above, providing the sensor module 14B in this manner may forego
the need for additional product lines, maintain upgradeability of
the controller without changing the core hardware thereof, and
provide additional processing resources.
[0091] In many environments, there are logical divisions between
spaces therein. For example, a logical way to divide a building is
by floor. Generally, the different lighting networks 12 in the
distributed lighting network 10 can be separated based on these
logical divisions. In the case of a building, a first lighting
network 12 may span all or a portion of a first floor, a second
lighting network 12 may span all or a portion of a second floor,
and so on. In general, floors are a good way to separate these
lighting networks 12 because there is a lesser need for
communication and cooperation between devices 14 located on
different floors. Accordingly, dividing the lighting networks 12 in
this manner reduces the overall traffic in each lighting network 14
and thus may improve the performance thereof. One or more border
routers 14D may bridge the various lighting networks 12 to form the
distributed lighting network 10. Communication between these
lighting networks 12 in the distributed lighting network 10 may
only be used for particular messages or types of communication
(e.g., high priority communication or the like), thereby allowing
each lighting network 12 to remain encapsulated and thus enjoy the
aforementioned reductions in network traffic.
[0092] In addition to forming different lighting networks 12 in a
space, it is sometimes desirable to form groups of devices 14 as
well. These groups may correspond, for example, with the devices 14
that are present within a particular room, group of rooms, or other
logical sub-division of space. Grouping devices 14 together may
cause them to share information to a higher degree than other
devices in a lighting network 12. In some embodiments, devices 14
in a group will respond to commands initiated from a controller 14C
in the group. Devices 14 outside the group will not respond to said
commands. Similarly, devices 14 in a group may respond to changes
in the environment detected by one or more sensors of one of the
devices 14 in the group. Devices 14 outside the group will not
respond to said environmental changes unless detected by one of the
devices 14 in their own group. In general, grouping devices 14 may
allow them to behave as a unit, which may be desirable in many
circumstances. Groups of devices may correspond with networking
groups having different privileges. For example, a group of devices
may behave as a sub-network of a larger lighting network 12.
Further, a group of devices may belong to a multicast IP group in
which messages are distributed among devices in the group and not
outside the group.
[0093] While the above description highlights the advantages of
dividing a number of devices 14 into networks and groups, doing so
has previously been a time consuming and difficult process.
Conventionally, devices 14 have been grouped manually, requiring a
significant investment of time to set up these groups. Further,
network formation processes have previously been over-inclusive,
often extending a lighting network 12 beyond a desired space and
causing network congestion due to an unnecessarily large number of
devices 14 in the lighting network 12. Previous solutions have
significantly simplified the grouping of lighting fixtures using
light modulation (referred to herein as
"lightcasting/lightcatching"), as performed by current
SmartCast.TM. lighting fixtures manufactured by Cree, Inc. of
Durham, N.C. Details regarding the automatic formation of groups in
this manner are discussed in U.S. patent application Ser. No.
13/782,022, the contents of which are hereby incorporated by
reference in their entirety. While the automatic grouping discussed
above may be applied to any of the devices 14 in the distributed
lighting network 10 to significantly improve the setup process of
grouping devices 14 together, several improvements have since been
made that further simplify network and group formation as discussed
below.
[0094] Previously, network formation (i.e., the inclusion of
devices in a lighting network 12) was a separate process than the
automatic grouping process discussed above. However, setup of a
lighting network 12 and one or more groups within the lighting
network 12 may be performed together in some embodiments. With
reference to FIG. 9, a number of devices 14, which could be any
combination of lighting fixtures 14A, sensor modules 14B,
controllers 14C, and/or border routers 14D, are uniquely referenced
as devices A through R and shown in different rooms (RM1-RM4) in a
space. In particular, device A is located in a first room RM1,
devices B-E are located in a second room RM2, devices I, J, L, M,
Q, and R are located in a third room RM3, devices N and 0 are
located in a fourth room RM4, and devices F, G, H, K, and P are
located in a fifth room RM5, which may be a hallway. Using
lightcasting and lightcatching, the devices 14 may be automatically
grouped into five different groups as discussed below.
[0095] FIG. 10 is a call flow diagram illustrating an exemplary
automatic grouping process according to one embodiment of the
present disclosure. First, the automatic grouping process is
initiated (step 100). The automatic grouping process may be
initiated in any number of different ways. For example, the
automatic grouping process may be initiated using a handheld
commissioning tool configured to communicate directly with each
device 14, may be initiated by a remote device 16 connected to the
distributed lighting network 10, or may be initiated by pressing a
physical button or otherwise activating a sensor on one of the
devices 14. In one embodiment, the automatic grouping process is
initiated as soon as the device 14 is powered on. In any event, the
automatic grouping process is generally initiated starting with a
single device 14, and in particular a single lighting fixture 14A.
Due to the nature of the automatic grouping process, the initiating
device 14 must be capable of providing a modulated light signal
(either visible or not). Generally, the lighting fixtures 14A are
the only devices 14 in the distributed lighting network 10 that are
capable of doing so, however, devices such as sensor modules 14B
and controllers 14C may be similarly configured to do so in some
embodiments. Devices 14 that are not capable of providing such a
modulated light signal may be configured to ignore such an
initiation process or to handoff the initiation process to a nearby
device 14 (i.e., a lighting fixture 14A) that is capable of doing
so. The initiating device 14 may be specifically chosen by a user,
chosen at random, or selected in any preferred manner. In some
embodiments, multiple devices 14 are simultaneously chosen to
initiate the automatic grouping process. This may speed up the
automatic grouping process by allowing it to simultaneously
propagate throughout a space in multiple directions, but also may
complicate the process, since it is necessary to know which device
14 is providing the modulated light signal and there is a
possibility that a single device 14 may simultaneously see a
modulated light signal from two different sources. Such a problem
may be solved by each device 14 providing a modulated light signal
at a particular frequency or frequency range in some embodiments.
By communicating the frequency or frequency range using wired or
wireless communications, the devices 14 looking for modulated light
signals can know which device 14 is providing which modulated light
signal, and thereby determine the relationship between the devices
14 as discussed below.
[0096] Regardless of how the initiating device(s) 14 are chosen,
said device(s) 14 first announce that they will begin providing a
modulated light signal via wired or wireless communication (step
102). This lets other devices 14 in the network know which
device(s) 14 are providing the modulated light signal upon
detection. Accordingly, such an announcement may include
identifying information about the device(s) 14 providing a
modulated light signal such as a device identifier or MAC address.
In additional embodiments, each device 14 providing a modulated
light signal may include an identifier thereof in the modulated
light signal itself. This principle may be used to uniquely
identify several different devices 14 that are simultaneously
providing modulated light signals. In general, any desired
information can be communicated in the modulated light signals
provided by the devices 14, which may be useful in streamlining the
automatic grouping process. Next, the initiating device(s) 14 begin
providing the modulated light signal (lightcasting) at a particular
frequency (step 104), while all other devices 14 in the network
detect the intensity of the modulated light signal (lightcatching)
using one or more sensors (step 106). In one embodiment, the
detecting devices 14 detect the intensity of the modulated light
signal using an ambient light sensor. Such a sensor is capable of
detecting the modulated light signal and a "signal strength" (i.e.,
a light intensity) thereof. In other embodiments, the detecting
devices 14 detect the intensity of the modulated light signal using
an image sensor such as a camera. The image sensor may provide
significantly more information about the modulated light signal,
such as a "signal strength" and a direction vector indicating the
direction of the device 14 providing the modulated light signal
with respect to the detecting device 14. Accordingly, in some
embodiments the detecting devices 14 may similarly detect this
additional information. The direction vectors discussed above may
allow the devices 14 to determine a real-space representation of
the devices 14 with respect to one another, as discussed in detail
in co-pending U.S. patent application Ser. No. 14/826,892, the
contents of which are hereby incorporated by reference in their
entirety.
[0097] The above described process is iterated such that each
device 14 capable of providing a modulated light signal does so,
and each other device 14 obtains an intensity value associated with
the modulated light signal from each one of these devices 14. The
resulting data can be viewed as a table such as the one shown in
FIG. 11. Notably, each device 14 may only know the modulated light
intensity measurements detected by its own sensors, and thus in
some embodiments the devices 14 may either periodically share the
relative intensity information with one another and with one or
more remote devices 16 (step 108).
[0098] By normalizing and/or otherwise operating on the intensity
data from the devices 14, a link table such as the one shown in
FIG. 12 can be obtained (step 110). For example, the light detected
from a neighboring lighting fixture 14A may first be divided by the
light detected from a receiving lighting fixture 14A to calibrate
the light measurements to the environment. Mutual light levels
detected by neighboring lighting fixtures 14A may be averaged
(e.g., the light level detected by a first lighting fixture 14A
from a second lighting fixture 14A may be averaged with the light
level detected by the second lighting fixture 14A by the first
lighting fixture 14A) to calibrate for differences in device 14
spacing and mounting heights. The light detected from a neighboring
lighting fixture 14A may then be divided by the light detected from
the nearest neighboring lighting fixture 14A (e.g., the light
detected by neighboring lighting fixtures 14A may be divided by the
strongest detected light signal) in order to group together devices
14 with strong connections. The relative light intensity detected
by each device 14 may then be examined to determine a threshold for
grouping, and the results shared with every device 14 in the
distributed lighting network 10 or a subset thereof (step 112).
[0099] The above may be a distributed process performed at least in
part by each device 14, may be determined by a single device 14 and
provided to all other devices 14, or may be determined by a remote
device 16 and provided to all other devices. The link table
indicates the adjacency of devices in the network, such that the
number indicates the number of devices 14 between any two devices
14 in the network. In some embodiments, each device 14 stores only
the links that it shares with other devices 14. In other
embodiments, each device 14 stores the entire link table for the
network. Devices 14 that are linked are grouped, such as device A
with itself, devices B-E with one another, devices F, G, H, K, and
P with one another, devices I, J, L, M, Q, and R with one another,
and devices N and 0 with one another. In this way, grouping between
the devices 14 can be accomplished automatically.
[0100] In addition to the automatic grouping discussed above, any
device 14 that is seen by any other device 14 in the automatic
grouping process is added to a lighting network 12. As discussed
above, a lighting network 12 may define a first level of
communication among devices, while a group may define a second and
more intensive level of communication among devices. Further, a
distributed network such as the distributed lighting network 10 may
define a third, less intensive level of communication among devices
14 therein. Adding only those devices 14 to the lighting network 12
that are in optical communication with one another may provide
several benefits as discussed above. For example, doing so may
prevent the over-inclusion of devices 14 into the lighting network
12 and thus prevent over-congestion. Generally, optical
communication is a good analogue for devices 14 in a lighting
network 12 that will want or need to communicate. Accordingly,
forming a lighting network 12 in this manner may be highly
advantageous. In some cases, certain devices 14 that should be
included in a network may be optically isolated from other devices
14 (e.g., may be located behind a closed door). Such devices 14 may
be added to the network manually as they are identified, for
example, by a commissioning tool or a remote device 16.
Alternatively, the automatic grouping process described above may
be periodically and/or persistently performed, such that when the
isolated device 14 is able to optically communicate with another
device 14 in the network (e.g., when a door is opened), the
isolated device 14 is automatically added to the network.
Periodically and/or persistently performing the automatic grouping
process may further increase the accuracy of automatic network and
group formation over time, thereby reducing the effort required to
setup the distributed lighting network 10.
[0101] Periodically and/or persistently performing the automatic
grouping process may be used to provide additional functionality as
well. For example, information such as heartbeat signals, certain
messages, and the like may be broadcast via light modulation that
is undetectable by the human eye, which may reduce the number of
messages sent over other network means and thereby reduce network
congestion. In some embodiments, light emitting devices in the
network may communicate solely via modulated light or may
facilitate communication among any number of devices using
modulated light. Further, the automatic grouping process may be
used to detect entrances and exits within a space by examining
discontinuities in detection between devices 14. In short, if a
device 14 detects the modulated light signal from another device 14
in a discontinuous manner, this may indicate that a moveable
obstacle such as a door is between these devices 14, and thus may
indicate that an entrance and/or exit is located between the
devices. Determining which devices 14 are near entrances and/or
exits may be useful in some situations, as discussed in detail
below.
[0102] As discussed above, any one of the lighting fixtures 14A,
sensor modules 14B, controllers 14C, and border routers 14D may
include the necessary hardware to detect modulated light (e.g., via
an ambient light sensor, image sensor, or the like). Accordingly,
any one of these devices 14 may be added to a lighting network 12
substantially automatically, which significantly simplifies the
setup of the lighting network 12. In some situations, supplemental
information from other sensors in the devices 12 may be used to
assist in the network formation and grouping process discussed
above. For example, atmospheric pressure sensor measurements may be
analyzed to determine which devices should join a particular
network. As discussed above, a floor of a building is generally a
good way to define the boundaries of a lighting network. In some
scenarios, however, the automatic grouping process discussed above
may fail to include every device in the network, or may include
devices in a lighting network 12 that are not desired. This may be
the case, for example, in an open atrium in which devices 14 on
different floors may see the light provided by one another, or when
a device 14 is optically isolated as discussed above. Accordingly,
FIG. 13 is a flow diagram illustrating a method for including
devices in a network with one another according to one embodiment
of the present disclosure.
[0103] To begin, a first device counter (i) and a second device
counter (j) are initialized (step 200). A number of atmospheric
pressure measurements are then received from a first device 14
indicated by the first device counter and a second device 14
indicated by the second device counter (step 202). Next, a
determination is made regarding whether or not a difference between
the atmospheric pressure measurements for the first device 14 and
the second device 14 are within a predetermined distance of one
another (step 204). This may indicate, for example, that the
devices 14 are located on the same floor in a building. In general,
ceiling mounted devices 14 such as lighting fixtures 14A will have
very similar atmospheric pressure measurements (atmospheric
pressure sensors are generally capable of detecting a difference
between a few vertical feet). Devices 14 that are less than a
predetermined distance below these ceiling mounted devices (e.g.,
sensor modules 14B, controllers 14C and border routers 14D) are
most likely also located on the same floor. Accordingly, if the
atmospheric pressure measurements (or the average of atmospheric
pressure measurements) of two different devices 14 are within the
predetermined distance of one another, the devices 14 are added to
the same network (step 206). If the atmospheric pressure
measurements are not within the predetermined distance of one
another, the second device counter is incremented (step 208) and a
determination is made regarding whether the second device counter
is greater than the total number of devices in the lighting network
12 (step 210). If the second device counter is greater than the
number of devices 14 in the lighting network 12, the network setup
process is exited (step 212). If the second device counter is not
greater than the number of devices 14 in the lighting network, the
process returns to step 200.
[0104] The process may be performed in response to a command to
initiate network formation, as discussed above, which may be
provided in any number of different ways. In response, the devices
14 may measure an atmospheric pressure and share this information
among each other or with the remote device 16. The process above
may then be performed at any level of granularity to determine
which devices 14 should be included in a particular network. Using
the above process may significantly simplify the setup of a network
when used alone. Further, the above process may be used in
conjunction with the automatic grouping process described above to
increase the accuracy thereof. For example, when used in
conjunction with the automatic grouping process, the above process
may allow devices 14 that are optically isolated from other devices
(e.g., in a closet) to join the network. In addition to atmospheric
pressure, any other sensor measurements may be combined with the
lightcasting data obtained above in order to further increase the
accuracy of the automatic grouping process. For example, radio
frequency ranging between devices 14 (e.g., time of flight ranging,
phase difference ranging, or any other known RF ranging techniques)
may be performed and used to verify or increase the accuracy of the
automatic grouping process.
[0105] The initial groups established by the automatic grouping
process discussed above may be further improved such that devices
14 in a network are more logically grouped in some situations. FIG.
14 shows an example of such a scenario. In particular, FIG. 14
shows the same devices 14 as in FIG. 9, but wherein the devices 14
are located in an open space with minimal separation. For example,
the devices 14 may be located in a warehouse. Accordingly, grouping
the devices 14 together via the automatic grouping process may
result in placing all of the devices 14 into a single group, since
there are no optical barriers to separate the devices 14. Since a
warehouse or other open space may be quite large, and since only
small portions of the space may be used at the same time, such a
grouping may be inefficient. For example, if all of the devices 14
are grouped together in FIG. 14, when one of the devices 14 detects
an occupancy event, all of the lighting fixtures located in the
space may turn on. If only a small portion of the space is being
used at this time, the space is then over-lit, thereby wasting
energy.
[0106] FIG. 15 is a flow diagram illustrating a method for
dynamically grouping devices 14 in a lighting network 12 over time
by analyzing sensor data from one or more devices 14 in the
distributed lighting network 10. First, sensor data is received
from multiple devices 14 in a group or lighting network 12 (step
300). One or more desired patterns are then detected in the sensor
data (step 302). Examples of such patterns include occupancy events
that are closely tied in time, occupancy events that occur
sequentially across a number of devices 14, sounds detected by a
number of different devices 14, changes in atmospheric pressure
detected by a number of different devices 14, changes in
temperature detected by a number of different devices 14, changes
in ambient light levels detected by a number of different devices
14, or some combination thereof. Virtually any sensor data may be
used to logically group devices. One or more devices 14 are then
grouped together based on the detected patterns in the sensor data
(step 304).
[0107] Grouping devices in this manner allows devices 14 to
dynamically form logical groups based on the occupancy patterns
within a space. The foregoing process may be carried out by a
single device 14, distributed among a number of devices 14, or
performed by a remote device 16. Using data obtained from the
sensors of the various devices 14 to form groups may become even
more accurate when done in a centralized manner by a remote device
16, as such a remote device 16 may have access to more historical
data and processing power than a single device 14 alone. For
example, performing dynamic grouping in a centralized manner may
allow for the application of machine learning algorithms, may
provide access to neural networks, or may otherwise provide
additional resources that are not available at the device level. In
general, analyzing sensor measurements between devices 14 over time
may be used to dynamically group the devices 14, which may provide
functional and logical groups of devices 14 without user input.
However, in some situations users may not wish to automatically
implement such grouping. In these situations, a suggestion to group
a number of devices 14 may be provided instead of automatically
grouping the devices 14. Only if a user provides confirmation will
such a group be formed. Since the distributed lighting network 10
allows for communication with remote devices 16, suggested
groupings of devices may be provided to a user, for example, via a
computer, a smart phone, or the like.
[0108] One notable pattern that often indicates that devices 14
should be grouped together is based on a correlation in the running
average of a sensor measurement or sensor measurements of
neighboring devices 14, as shown in Equation (1):
|RAS.sub.D1)-RAS.sub.D2|>GR.sub.THSH
where RAS.sub.D1 is the running average of a sensor measurement for
a first device 14, RAS.sub.D2 is the running average of a sensor
measurement for a second device 14, and GR.sub.THSH is a grouping
threshold. A running average of a sensor measurement may be
maintained by each device 14 according to well-known formulae. In
some embodiments, however, a lightweight "running average" may be
maintained to save processing power and memory storage in each
device 14. A lightweight running average may be obtained according
to Equation (2):
LRA=.alpha.SM.sub.CURR+.beta.LRA.sub.PREV
where LRA is the lightweight running average, SM.sub.CURR is a
current sensor measurement, LRA.sub.PREV is a previously calculated
lightweight running average, .alpha. is a first blending factor,
and .beta. is a second blending factor. The blending factors may be
predetermined by experimentation in some embodiments, or may be
adaptive. Using the lightweight running average described above may
save memory and processing resources when compared to computing a
full running average. In situations where memory and processing
power are limited, this may be highly advantageous.
[0109] By way of example, neighboring devices 14 (which may be
determined by the link table discussed above with respect to FIG.
12) whose running average of detected occupancy events are
relatively close to one another indicate that they are in an area
that is often used together, and thus can be grouped. As discussed
herein, an occupancy event occurs when a human enters or leaves a
field of view of a sensor in a device 14. Detecting such events may
be important, for example, so that a lighting fixture or group of
lighting fixtures can adjust a light output level thereof as light
is required or desired in a particular space. Further, occupancy
events may provide useful information about how a particular space
is currently or historically used, and thus may provide useful
information for characterizing a space. Occupancy events are
generally detected by a PIR sensor and/or image sensor, however,
any suitable means for detecting an occupancy event may be used
without departing from the principles of the present
disclosure.
[0110] As another example, neighboring devices 14 whose running
average of ambient light levels are similar may also be grouped.
This may be especially useful in light emitting devices configured
to use "daylight harvesting," such as current SmartCast.TM.
lighting fixtures manufactured by Cree, Inc. of Durham, N.C.
Details of daylight harvesting are discussed in U.S. patent
application Ser. No. 14/681,846, the disclosure of which is hereby
incorporated by reference in its entirety. In short, daylight
harvesting involves changing the amount of light provided by a
lighting fixture 14A based on detected ambient light levels in the
space such that a task surface is illuminated at substantially the
same brightness throughout the day (even as the amount of light
provided, for example, through a window, changes). In some cases,
when different lighting fixtures 14A detect and act upon ambient
light levels individually, differences in the light output of
neighboring or nearby lighting fixtures 14A can be quite different,
creating a visual disruption. Using the principles described above,
devices 14 with similar ambient light levels could be grouped.
These grouped devices 14 may be configured such that lighting
fixtures 14A in the group provide the same light intensity, which
may prevent uneven gradients of light between lighting fixtures 14A
due to manufacturing tolerances, slight changes in the detected
ambient light level between devices 14, and the like.
[0111] Regardless of how the distributed lighting network 10 is
formed and devices 14 grouped, it may be desirable to secure the
network such that only devices with verified security credentials
can interact with the devices 14. In some situations, it may also
be desirable for communications in the distributed lighting network
10 to conform to one or more networking protocols, such as the
Thread home automation networking protocol. Details of the Thread
home automation networking protocol can be found in "Thread Stack
Fundamentals" published Jul. 13, 2015 (http://www.threadgroup.org),
the contents of which are hereby incorporated by reference in their
entirety. Using known networking protocols to communicate in the
distributed lighting network 10 may increase compatibility with
third party products such that the devices 14 may be easily
integrated with preexisting or later obtained products. Prior
approaches to security for lighting fixtures 14A and other
connected devices 14 have generally been focused on adding a single
device 14 to a network at a time, for example, based on a
hard-coded product serial number, MAC address, or the like, which
is manually provided by a user. Such an approach is generally not
feasible in the distributed lighting network 10 due to the large
number of lighting fixtures 14A and other devices 14 therein. That
is, individually adding each device 14 to the distributed lighting
network 10 would be an arduous and time consuming process.
[0112] In one embodiment, common security credentials are provided
in each of the devices 14 in the distributed lighting network 10
during a factory calibration process. These common security
credentials are then used to form a secure network between the
devices 14 in an initial setup procedure, such as during network
formation as described above. Once the distributed lighting network
10 is initially formed using the common security credentials,
updated security credentials may be generated and provided to the
devices 14 in the network such that the distributed lighting
network 10 is secured by unique security credentials. Using common
security credentials during initial formation of the distributed
lighting network 10 bypasses the conventional individual device
approach to adding devices to a secure network, thereby allowing
the distributed lighting network 10 to be formed with minimal user
intervention and hassle. Later updating of the security credentials
then provides a highly secure distributed lighting network 10.
[0113] FIG. 16 is a flow diagram illustrating a factory calibration
process for a lighting fixture 14A or other device 14 in the
distributed lighting network 10 according to one embodiment of the
present disclosure. First, the device functionality of the lighting
fixture 14A or device 14 is programmed into the memory thereof
(step 400). This may include instructions for a lighting fixture
14A to properly control the light output thereof based on sensor
measurements and communications with other devices 14 in the
distributed lighting network 10 as discussed above. Next, common
security credentials are programmed into the memory of the lighting
fixture 14A or other device 14 (step 402). Programming common
security credentials into the memory of the lighting fixture 14A or
other device 14 allows for the creation of a secure distributed
lighting network 10 with little to no user intervention as
discussed in detail below.
[0114] FIG. 17 is a flow diagram illustrating a process for
operating a lighting fixture 14A to create or join a secure
distributed lighting network 10 according to one embodiment of the
present disclosure. While the process is discussed below with
respect to lighting fixtures 14A, any other device 14 in the
distributed lighting network 10 may similarly perform the process
to create or join a secured distributed lighting network 10. First,
the lighting fixture 14A is powered on (step 500). The lighting
fixture 14A then attempts to join a common network using common
network security credentials that are pre-installed during a
factory calibration process (step 502). This may include attempting
to join the common network on each one of a number of different
channels by sending a request join message or the like and waiting
for a response. Using the common security credentials in attempting
to join the common network may include providing a key to another
device 14 that is based on the common security credentials. For
example, using the common security credentials to join the common
network may include using the common security credentials in a
transport layer security (TLS), datagram transport layer security
(DTLS), and/or secure sockets layer (SSL) authentication process.
In one embodiment, the common security credentials are used as a
network-wide key in a Thread network, as detailed in "Thread
commissioning" published Jul. 13, 2015, the contents of which are
hereby incorporated by reference in their entirety. The lighting
fixture 14A may thus use the common security credentials
accordingly when attempting to join the common network.
[0115] A determination is then made whether the common network was
successfully joined (step 504). If the common network was
successfully joined, the process may end. If the common network was
not successfully joined, the lighting fixture 14A may wait a
predetermined amount of time before creating the common network
using the common security credentials (step 506). Creating the
common network may include designating oneself as the network
"leader", listening for network join requests from other devices
14, and facilitating their addition to the network. For example,
creating the common network may include receiving a join request
from another device 14, verifying the common security credentials
from the device 14, assigning an address to the device 14, and
providing the address back to the device 14 or otherwise indicating
a successful network join. Verifying the common security
credentials of other devices 14 attempting to join the common
network may include analyzing a key from a device 14 to ensure that
it can be traced back to the common security credentials. For
example, the lighting fixture 14A may use the common security
credentials in a transport layer security (TLS), datagram transport
layer security (DTLS), and/or secure sockets layer (SSL)
authentication process. In one embodiment, the common security
credentials are used as a network-wide key in a Thread network as
discussed above and verified by the lighting fixture 14A
accordingly.
[0116] Notably, the foregoing process may be performed alongside
the network formation and grouping processes discussed above. In
one embodiment, the lighting fixture 14A that creates the common
network only allows other devices 14 that were identified via the
lightcasting/lightcatching process discussed above to join the
common network, or only allows other devices 14 with similar
atmospheric pressure readings to join the common network. This may
prevent the undesirable expansion of the network in order to
maintain the security thereof. Further, this may occur at the same
time as the lightcasting/lightcatching process such that network
join requests are provided during lightcasting of a particular
lighting fixture 14A and approved upon lightcatching from the
originating lighting fixture 14A or a lighting fixture 14A that is
connected through one or more neighbors to the originating lighting
fixture 14A.
[0117] FIG. 18 is a call flow diagram illustrating the process
described above in FIG. 17. While the process is discussed below
with respect to lighting fixtures 14A, any other device 14 in the
distributed lighting network 10 may similarly perform the process
to create or join a secured distributed lighting network 10. To
start, a first lighting fixture 14A(1) sends a network join
request, for example, via a local broadcast to one or more other
lighting fixtures 14A (step 600). In the present example, a second
lighting fixture 14A(2) and a third lighting fixture 14A(3) receive
the network join request, but since they have not established a
common network, they do not respond. Accordingly, the first
lighting fixture 14A(1) creates the common network (step 602). As
discussed above, creating the common network may include listening
for network join requests from other devices 14, and facilitating
their addition to the network. For example, creating the common
network may include designating oneself as the network "leader",
receiving a join request from another device 14, verifying the
common security credentials from the device 14, assigning an
address to the device 14, and providing the address back to the
device 14 or otherwise indicating a successful network join.
[0118] The second lighting fixture 14A(2) then sends a network join
request, which is received by the first lighting fixture 14A(1)
(step 604). The network join request may similarly be received by
the third lighting fixture 14A(3), but since the third lighting
fixture 14A(3) did not create the network (i.e., is not the network
leader), the third lighting fixture 14A(3) will not respond to the
message. The first lighting fixture 14A(1) adds the second lighting
fixture 14A(2) to the common network (step 606), for example, by
verifying the common security credentials of the second lighting
fixture 14A(2) and assigning an address thereto. The first lighting
fixture 14A(1) then sends an acknowledgement message back to the
second lighting fixture 14A(2) to indicate that the network was
successfully joined (step 608).
[0119] The third lighting fixture 14A(3) then sends a network join
request, which is received by the first lighting fixture 14A(1)
(step 610). The network join request may similarly be received by
the second lighting fixture 14A(2), but since the second lighting
fixture 14A(2) did not create the network (i.e., is not the network
leader), the second lighting fixture 14A(2) will not respond to the
message. The first lighting fixture 14A(1) adds the third lighting
fixture 14A(3) to the common network (step 612) as discussed above.
The first lighting fixture 14A(1) then sends an acknowledgement
message back to the third lighting fixture 14A(3) to indicate that
the network was successfully joined (step 614). Additional devices
14 may be added to the common network in a similar manner.
[0120] In some embodiments, the common network may be a Thread
network such that messaging in the network conforms to the Thread
home automation networking protocol discussed above. Generally,
devices are added to a Thread network on an individual basis,
requiring manual intervention from a user. Using the process
discussed above, multiple lighting fixtures 14A and other devices
14 may be added to a Thread network due to the shared common
security credentials that are pre-installed thereon. Such an
approach significantly simplifies the setup of a secure
network.
[0121] In the process described above in FIG. 17, if a lighting
fixture 14A was unsuccessful in joining a common network, it
created the common network. However, this may not always be the
case. In some embodiments, the common network may be created by
another device 14, such as a commissioning tool. Accordingly, FIG.
19 is a flow diagram illustrating a process for operating a
lighting fixture 14A to join a secure distributed lighting network
10 according to one embodiment of the present disclosure. As
discussed above, the lighting fixture 14A is first powered on (step
700). The lighting fixture 14A then attempts to join the common
network using the common network security credentials as discussed
above (step 702). A determination is then made whether the lighting
fixture 14A successfully joined the common network (step 704). If
the common network was successfully joined, the process ends.
However, if the common network was not successfully joined, the
process returns to step 702 to attempt to join the common network
again. The lighting fixture 14A may continue to try and join the
common network until it is successful, rather than creating the
common network itself, since the common network is created by
another device in such an embodiment.
[0122] FIG. 20 is a call flow diagram illustrating details of the
process described above in FIG. 19. First, each one of a first
lighting fixture 14A(1), a second lighting fixture 14A(2), and a
third lighting fixture 14A(3) each send a network join message via
local broadcast (step 800). While the messages are received at each
other device 14, a common network has not yet been created and thus
there are no responses. At some point in time, a device 14 creates
the common network (802). As discussed above, the device 14 may be
a commissioning tool operated by a user, or may be any other device
suitable for creating the common network. As discussed above,
creating the common network may include listening for network join
requests from other devices 14, and facilitating their addition to
the network. For example, creating the common network may include
designating oneself as the network "leader", receiving a join
request from another device 14, verifying the common security
credentials from the device 14, assigning an address to the device
14, and providing the address back to the device 14 or otherwise
indicating a successful network join.
[0123] A network join request is then provided again from the first
lighting fixture 14A(1) (since the first lighting fixture 14A(1) is
configured to continue to try to join the common network as
discussed above) and received at the device 14 (step 804). While
the second lighting fixture 14A(2) and the third lighting fixture
14A(3) may similarly receive the network join request, these
devices are not network leaders and thus do not respond thereto.
The device 14 adds the first lighting fixture 14A to the common
network (step 806), for example, by verifying the common security
credentials of the first lighting fixture 14A(1) and assigning an
address thereto. The device 14 then sends an acknowledgement
message back to the first lighting fixture 14A(1) to indicate that
the network was successfully joined (step 808).
[0124] A network request is provided again from the second lighting
fixture 14A(2) and received at the device 14 (step 810). While the
first lighting fixture 14A(1) and the third lighting fixture 14A(3)
may similarly receive the network join request, these devices are
not network leaders and thus do not respond thereto. The device 14
adds the second lighting fixture 14A(2) to the common network (step
812), for example, by verifying the common security credentials of
the second lighting fixture 14A(2) and assigning an address
thereto. The device 14 then sends an acknowledgement message back
to the second lighting fixture 14A(2) to indicate that the network
was successfully joined (step 814).
[0125] A network request is provided again from the third lighting
fixture 14A(3) and received at the device 14 (step 816). While the
first lighting fixture 14A(1) and the second lighting fixture
14A(2) may similarly receive the network join request, these
devices are not network leaders and thus do not respond thereto.
The device 14 adds the third lighting fixture 14A(3) to the common
network (step 818), for example, by verifying the common security
credentials of the third lighting fixture 14A(3) and assigning an
address thereto. The device 14 then sends an acknowledgement
message back to the third lighting fixture 14A(3) indicating that
the network was successfully joined (step 820).
[0126] In some embodiments, a lighting fixture 14A may start the
common network, but may require initiation to do so, for example,
by another device 14 such as a commissioning tool. Accordingly,
FIG. 21 is a flow diagram illustrating a process for operating a
lighting fixture 14A to create or join a secure distributed
lighting network 10 according to one embodiment of the present
disclosure. As discussed above, the lighting fixture 14A is first
powered on (step 900). The lighting fixture 14A then attempts to
join the common network using the common security credentials as
discussed above (step 902). A determination is then made whether
the lighting fixture 14A successfully joined the common network
(step 904). If the common network was successfully joined, the
process ends. However, if the common network was not successfully
joined, it is determined if a commissioning signal was received
(step 906). The commissioning signal may indicate that the lighting
fixture 14A should create the common network, and may be provided
by another device 14 such as a commissioning tool operated by a
user. In one embodiment, the commissioning signal is provided as an
optical signal to an ambient light sensor or image sensor in the
lighting fixture 14A, however, the commissioning signal may be
provided by any suitable means without departing from the
principles described herein.
[0127] If the commissioning signal was received, the lighting
fixture 14A creates the common network (step 908). As discussed
above, creating the common network may include listening for
network join requests from other devices 14, and facilitating their
addition to the network. For example, creating the common network
may include designating oneself as the network "leader", receiving
a join request from another device 14, verifying the common
security credentials from the device 14, assigning an address to
the device 14, and providing the address back to the device 14 or
otherwise indicating a successful network join.
[0128] FIG. 22 is a call flow diagram illustrating details of the
process described in FIG. 21. First, each one of a first lighting
fixture 14A(1), a second lighting fixture 14A(2), and a third
lighting fixture 14A(3) each send a network join message via local
broadcast (step 1000). While the messages are received at each
other device 14, a common network has not yet been created and thus
there are no responses. At some point in time, a commissioning
signal is provided from a device 14 (e.g., a commissioning tool) to
the first lighting fixture 14A(1) (step 1002). As discussed above,
the commissioning signal may be provided as an optical signal and
received via an ambient light sensor or image sensor on the first
lighting fixture 14A(1), or by any other suitable means. In
response to the commissioning signal, the first lighting fixture
14A(1) creates the common network (step 1004). As discussed above,
creating the common network may include listening for network join
requests from other devices 14, and facilitating their addition to
the network. For example, creating the common network may include
designating oneself as the network "leader", receiving a join
request from another device 14, verifying the common security
credentials from the device 14, assigning an address to the device
14, and providing the address back to the device 14 or otherwise
indicating a successful network join.
[0129] The second lighting fixture 14A(2) then sends a network join
request, which is received by the first lighting fixture 14A(1)
(step 1006). While the network join request may similarly be
received by the third lighting fixture 14A(3) and the device 14,
these devices are not network leaders and thus do not respond
thereto. The first lighting fixture 14A(1) adds the second lighting
fixture 14A(2) to the common network (step 1008), for example, by
verifying the common security credentials of the second lighting
fixture 14A(2) and assigning an address thereto. The first lighting
fixture 14A(1) then sends an acknowledgement message back to the
second lighting fixture 14A(2) to indicate that the network was
successfully joined (step 1010).
[0130] The third lighting fixture 14A(3) then sends a network join
request, which is received by the first lighting fixture 14A(1)
(step 1012). While the network join request may similarly be
received by the second lighting fixture 14A(2) and the device 14,
these devices are not network leaders and thus do not respond
thereto. The first lighting fixture 14A(1) adds the third lighting
fixture 14A(3) to the common network (step 1014) as discussed
above. The first lighting fixture 14A(1) then sends an
acknowledgement message back to the third lighting fixture 14A(3)
to indicate that the network was successfully joined (step
1016).
[0131] The device 14 then sends a network join request, which is
received by the first lighting fixture (step 1018). While the
network join request may similarly be received by the second
lighting fixture 14A(2) and the third lighting fixture 14A(3),
these devices are not network leaders and thus do not respond
thereto. The first lighting fixture 14A(1) adds the device 14 to
the common network (step 1020) as discussed above. The first
lighting fixture 14A(1) then sends an acknowledgement back to the
device 14 to indicate that the network was successfully joined
(step 1022).
[0132] After the common network has been established using any of
the processes described above, or any other suitable processes that
leverage the common security credentials for initial formation of
the network, it is desirable to update the security credentials for
the devices 14 in the network such that they are unique.
Accordingly, FIG. 23 is a flow diagram illustrating a process for
updating the security credentials for the devices 14 in a secured
distributed lighting network 10 according to one embodiment of the
present disclosure. The following process may be performed by any
lighting fixture 14 or device 14 in the secure distributed lighting
network 10. In one embodiment, the process is performed by a
commissioning tool or mobile device that allows for user input.
First, a user provided PIN is received (step 1100). The user
provided PIN may include n characters, and may be numeric or
alphanumeric. Based on the user provided PIN, updated security
credentials are generated (step 1102). Generating the updated
security credentials from the user provided PIN may include hashing
or otherwise operating on the user provided PIN in some
embodiments. Finally, the updated security credentials are provided
to at least one other device 14 in the secure distributed lighting
network 10 (step 1104). The device receiving the updated security
credentials may then forward the updated security credentials to
one or more other devices 14 in order to propagate them across the
secure distributed lighting network 10. Once the updated security
credentials are received at a device 14, that device 14 may then
communicate using the updated security credentials. As the updated
security credentials are provided to every device 14 in the secured
distributed lighting network 10, the common security credentials
are no longer used.
[0133] If a new device 14 including the common security credentials
is provided, the updated security credentials must be provided to
the device 14 before it can join the secure distributed lighting
network 10. Such a process may be facilitated by a device 14 such
as a commissioning tool, which may be placed in a mode to
communicate using both the common security credentials and the
updated security credentials in order to provide the updated
security credentials to the new device 14.
[0134] FIG. 24 is a call flow diagram illustrating details of the
process discussed above in FIG. 23. First, a PIN is provided to a
device 14 (step 1200). Updated security credentials are then
generated by the device 14 based on the PIN as discussed above
(step 1202). The updated security credentials are then provided to
a first lighting fixture 14A(1) (step 1204), which forwards the
updated security credentials to a second lighting fixture 14A(2)
(step 1206), which in turn forwards the updated security
credentials to a third lighting fixture 14A(3) (step 1208). In this
way, the secure distributed lighting network 10 may be provided
with unique security credentials.
[0135] The link table information shown in FIG. 12 may be useful
not only for network formation and grouping, but may be used to
implement additional functionality in the distributed lighting
network 10. One such feature is referred to herein as "fluid
occupancy," the basic premise of which is illustrated in FIGS. 25A
through 25C. As shown in FIGS. 25A through 25C, a single device 14
in a group of devices 14 may detect an occupancy event. The device
14 that detects the occupancy event is referred to as the
"originating device" and is illustrated with a cross-hatch pattern.
In response to the detection of the occupancy event, the
originating device 14 will begin providing light if it is capable
of doing so (e.g., if it is a lighting fixture 14A), or will simply
notify other devices 14 in the group if it is not capable of doing
so. Neighboring lighting fixtures 14A of the originating device 14
will similarly turn on, forming a "bubble" of light around the
originating device 14. These neighboring illuminated lighting
fixtures 14A are illustrated with a hatch pattern. The number of
neighboring lighting fixtures 14A that turn on in response to the
detection of an occupancy event by the originating device 14 may be
adjusted. For example, only direct neighbors to the originating
device 14 may turn on, neighbors separated from the originating
device 14 by one other device 14 may turn on as well, or neighbors
separated from the originating device 14 by up to n other devices
14 may turn on as well. The number of devices 14 located between
two devices 14 may be readily determined using the link table
discussed above with respect to FIG. 12. As shown in FIGS. 25A
through 25C, as an occupancy event is detected by a different
device 14 (e.g., as an individual moves closer to another device
14), that device 14 then becomes the originating device 14, and the
neighboring lighting fixtures 14A turn on. The result is a "bubble"
of light that is capable of following an individual as they move
throughout a space. This light "bubble" may provide security by
allowing an individual to see around them while simultaneously
saving energy by preventing over-lighting a space. Notably, the
light output of each lighting fixture 14A surrounding the
originating device 14 may diminish in proportion to the distance of
the lighting fixture 14A from the originating device 14. For
example, lighting fixtures 14A that are directly adjacent to the
originating device 14 may provide maximum light output, lighting
fixtures 14A that are one device 14 removed from the originating
device 14 may provide 50% light output, etc.
[0136] FIG. 26 is a call flow diagram illustrating a process for
implementing the fluid occupancy functionality discussed above.
First, an originating device 14 detects an occupancy event (step
1300). The originating device 14 then indicates that an occupancy
event has been detected to one or more lighting fixtures 14A in the
group or lighting network 12 (step 1302). Each lighting fixture 14A
that is notified of the occupancy event checks if it is within n
devices 14 of the originating device 14 (step 1304), where n is the
preferred threshold for surrounding illumination. This is
determined, for example, by referencing the link table discussed
above in FIG. 12. If necessary, each lighting fixture 14A then
adjusts the light output thereof (step 1306). Each lighting fixture
14A may also initiate an occupancy timeout in response to the
indicating of an occupancy event by the originating device 14. This
occupancy timeout may be counted against a real-time clock. On
expiration of the occupancy timeout, the lighting fixture 14A may
reset the light output thereof to a previously stored setting, or
may turn off altogether. Notably, the occupancy timeout in each
lighting fixture 14A may execute independently. In some cases,
different lighting fixtures 14A may receive notifications from
multiple neighboring devices 14 that an occupancy event has
occurred. In the case where a different light output level is used
based on the distance of the lighting fixture 14A from the
originating device, there may be a conflict regarding which light
output level a lighting fixture 14A should provide. Generally, this
may be resolved by using the highest light output level, the lowest
light output level, an average of the highest light output level
and the lowest light output level, or any other suitable value.
[0137] While the above example is primarily discussed in terms of
occupancy events, any number of different sensor measurements may
be used to initiate a similar process. For example, the detection
of an object (e.g., via an image sensor) may cause a similar
illumination pattern to that discussed above. For example, a
similar "bubble" of light may follow cars around a parking garage,
which may forego the need for illuminating the entire garage, thus
saving significant amounts of energy.
[0138] The fluid occupancy process discussed above may be used
primarily within groups of devices 14. However, in some
embodiments, devices 14 outside of a group in which an occupancy
event is detected may also be illuminated. For example, the lights
in neighboring groups may participate in the fluid occupancy
process as occupancy events are detected near a border of the group
in which the occupancy event is detected and the neighboring group.
For example, as an individual moves through a hallway, lighting
fixtures 14A in the hallway may illuminate an area surrounding the
individual, and lighting fixtures 14A in rooms located off the
hallway may illuminate the rooms as the individual walks by. This
may provide the individual a greater sense of security by allowing
the individual to view the inside of the rooms. In some
embodiments, the lighting fixtures 14A in neighboring groups may
provide a lower light level than the lighting fixtures 14A in a
group in which an occupancy event was detected.
[0139] In some embodiments, the devices 14 may attempt to predict
the path of movement of an individual or object, and may adjust the
output of one or more lighting fixtures 14A to illuminate this
predicted path. As occupancy events are detected by devices 14 in a
group, other devices 14 in the group may receive notifications of
these occupancy events. A first occupancy event may occur n devices
14 away, a second occupancy event may occur n-1 devices away, and
so on, until it may be predicted that a particular device 14 will
be next to detect an occupancy event. Such prediction may become
significantly easier when image sensors are involved, as motion
vectors may be computed for objects using data from the image
sensors. The predicted path may then be illuminated.
[0140] In addition to the above, the link table may be used to
illuminate a desired path to a particular location within a space.
Such a feature may be used, for example, to illuminate a path
towards exits during an emergency. In such an embodiment, a device
14 at or near a desired point in the space, referred to as a "key"
device 14, may be designated, and the neighboring lighting fixtures
14A of the key device 14 may sequentially turn on in sequence to
their neighbor ranking to the key device 14. This results in a
pattern of light that directs attention towards the designated
feature, and thus may be used to guide an individual towards the
designated feature. FIGS. 27A through 27D illustrate the basic
premise of this feature. As shown, a key device 14 is illustrated
with a cross-hatch pattern. Lighting fixtures 14A at a maximum
neighbor rank away from the key device (two in the present
embodiment) are illuminated together in FIG. 27A, followed by
lighting fixtures 14A that of the next lowest neighbor ranking in
FIG. 27B (one in the present embodiment), and finally be those
devices 14 with the lowest neighbor ranking (zero in the present
embodiment) in FIG. 27C. If the key device 14 is capable of
providing a light output, it may then do so alone as shown in FIG.
27D. It is apparent that such a pattern of light will direct an
observer's attention towards the key device 14, which may be useful
in any number of different scenarios.
[0141] As discussed above, it may thus be desirable to know which
devices 14 are near an entrance and/or exit to a space. In order to
make such a determination, occupancy events may be analyzed over
time. In a group of devices 14, the first device 14 to see an
occupancy event will generally be the closest to an entrance, while
the last device 14 to see an occupancy event will generally be
closest to an exit. While this may not be true every time due to
false detections, misdetections, timing, etc., a long running
average of the first and last devices 14 in a group that observe an
occupancy event are extremely likely to be the nearest to an
entrance and exit of the group, respectively. This information may
be used to designate entrance and exit devices 14, which may
provide special functionality as discussed below.
[0142] FIG. 28 is a flow diagram illustrating a method for
detecting a device 14 near an entrance and/or exit to a space
according to one embodiment of the present disclosure. One or more
occupancy events detected by the devices 14 in a group are first
provided (step 1400). Each occupancy event is then analyzed to
determine if it was the first occupancy event detected after a
previous occupancy timeout (step 1402). When an occupancy event is
detected by a device 14, an occupancy timeout is initiated. If an
additional occupancy event is not detected before the occupancy
timeout expires, it is determined that an individual is no longer
present in the space. One or more lighting fixtures 14A in the
group may then adjust the light output provided therefrom. If an
occupancy event was the first to occur after a previous occupancy
timeout, an entrance device counter associated with the device 14
that detected the occupancy event is incremented (step 1404). The
entrance device counter is then compared to a threshold value (step
1406). This threshold value may be fixed, or may be a relative
value that is determined with respect to the entrance device
counter of each other device 14 in the group. If the entrance
device counter is above the threshold value, the device 14 is
designated as an entrance device (step 1408), and the process
returns to step 1410. If the entrance device counter is not above
the threshold value, the process returns to step 1410. If the
occupancy event was not the first to occur after a previous
occupancy timeout, the process skips step 1404, step 1406, and step
1408, proceeding directly to step 1410. Each occupancy event is
then analyzed to determine if it was the last occupancy event
detected before an occupancy timeout (step 1410). If an occupancy
event was the last before an occupancy timeout, an exit device
counter for the device that detected the occupancy event is
incremented (step 1412). The exit device counter is then compared
to a threshold value (step 1414). As discussed above, the threshold
value may be fixed, or may be relative to a value that is
determined with respect to the exit device counter for each other
device 14 in the group. If the exit device counter is not above the
threshold value, the process returns to step 1402. If the exit
device counter is above the threshold value, the device 14 is
designated as an exit device (step 1416).
[0143] In one embodiment, one or more lighting fixtures 14A may
indicate a desired placement of a border router 14D in a space.
Accordingly, FIG. 29 is a flow diagram illustrating a method for
indicating a preferred placement of a border router 14D in a space
according to one embodiment of the present disclosure. First, a
desired position for a border router 14D in a space is determined
by the devices 14 in a lighting network 12 (step 1500). Such a
desired position may be determined, for example, by examining the
number of network collisions throughout the lighting network 12 and
finding a spot where the collisions are lowest, by examining the
total network traffic throughout the lighting network 12 and
finding a spot where the traffic is the lowest, examining the
received signal strength of each device 14 in the lighting network
12 and determining where there is the least amount of external
interference therein, or by examining any other network performance
or other parameter that is detectable by the devices 14 in the
network. The desired position of the border router 14D is then
indicated by one or more lighting fixtures 14 in the network (step
1502). This can be done similar to the process discussed above by
directing an individual's attention towards the desired position,
or may be indicated by a single lighting fixture 14A, or in any
other desired fashion. By detecting and indicating a desired
position for a border router 14D, the performance of the border
router 14D may be improved by optimizing the communication between
one or more devices in the network and the border router 14D.
[0144] In addition to the above, the link table discussed above in
FIG. 12 may be used to improve an ambient light sensor calibration
process of devices 14 in a lighting network 12. Accordingly, FIG.
30 is a flow diagram illustrating a method for calibrating the
ambient light sensors of one or more devices 14 in a lighting
network 12. Upon initiation of an ambient light sensor calibration
process at a particular device 14, which may be particularly chosen
by a user, chosen at random, or chosen in any desired fashion, the
light output of neighboring lighting fixtures 14A to the device is
set to zero (step 1600). This is necessary to avoid contaminating
ambient light readings with the light output of the neighboring
lighting fixtures 14A. In some embodiments, any lighting fixture
14A from which light was detected by the device 14 in the automatic
grouping process discussed above may set its light output to zero
for proper calibration to occur. Next, the ambient light sensor(s)
of the device 14 are calibrated (step 1602). The light output of
the neighboring lighting fixtures 14A is then restored to its
previous level (step 1604). Notably, this ambient light sensor
calibration process may significantly improve over previous
approaches, which adjusted the light output of every lighting
fixture 14A in a space to zero in order to calibrate the ambient
light sensors of the devices 14 therein. While waiting to confirm
that each lighting fixture 14A had properly adjusted the light
output thereof, the space would be unlit, and therefore may be
unusable for a period of time. The above process allows the
majority of the space to remain usable during such a calibration
period.
[0145] Previously, devices 14 in a wireless lighting network 12A
communicated with one another using a single wireless
communications channel, which may have been chosen at random or by
a user. This often resulted in sub-optimal wireless communication
between the devices 14. In some cases, the wireless communications
channel chosen for the devices 14 was based on network conditions,
however, the network conditions for one device 14 or group of
devices 14 may vary significantly throughout a space. For example,
one device 14 or group of devices 14 may be located near a large
source of radio frequency (RF) noise such as an RF device operating
in a similar frequency spectrum, or may be located near an obstacle
to wireless signals such as a metal structure. Accordingly, FIG. 31
is a call-flow diagram illustrating a method for optimizing a
wireless communications channel for communication between devices
14 in a wireless lighting network 12A according to one embodiment
of the present disclosure.
[0146] First, each device 14 determines an optimal communications
channel (step 1700). Each device 14 may make this determination,
for example, based on a local analysis of network traffic, network
collisions, or any other network performance metric that is
measurable by each device 14. The optimal channel determined by
each device 14 is then shared with each other device 14 in the
wireless lighting network 12A (step 1702). Each device 14 may store
the optimal channel determined by each other device 14 (step 1704).
Each device 14 may further determine which shared communications
channel should be used in the wireless lighting network 12A or a
subset thereof, such as a group (step 1706). For example, if a
majority of devices 14 in the wireless lighting network 12A
determined the same optimal communications channel, this channel
may be used for communication within the wireless lighting network
12A. Similarly, if the majority of devices 14 in a group determined
the same optimal communications channel, this channel may be used
for communication within the group. Notably, each device 14 may
communicate on a different communications channel with each other
device 14 based on the optimal communications information that was
previously shared amongst the devices 14. For example, a device 14
may look-up the optimal communications channel for another device
14 before communication therewith, and use this optimal
communications channel. This may occur at any level of granularity,
such as on a device 14 level, on a group level, or on a network
level. The determined shared communications channel may then be
shared between the devices 14 (step 1708) so that it can be used as
discussed above.
[0147] FIG. 32 is a call-flow diagram illustrating a method for
optimizing a wireless communications channel for communication
between devices 14 in a wireless lighting network 12A according to
an additional embodiment of the present disclosure. First, the
devices 14 in a network provide network information about the
network to a border router 14D (step 1800). The network information
may include any network parameters that are measureable by the
devices 14 as discussed above. The border router 14D then
determines an optimal communications channel for each device 14 in
the wireless lighting network 12A (step 1802). Further, the border
router 14D may determine the optimal shared communications channel
for the wireless lighting network 12A or any subset thereof such as
the groups in the wireless lighting network 12A (step 1804). The
border router 14D may then share these optimal communications
channels and optimal shared communications channel with each device
14 (step 1806).
[0148] The features described above allow for the formation of an
improved distributed lighting network 10. The distributed lighting
network 10 is unique in that it provides intelligent devices 14 at
fixed points throughout a space. These devices 14 may be leveraged
to introduce significant new functionality into a space, and to
provide valuable insights about the space. As an infrastructure for
lighting is ubiquitous in most modern spaces, the distributed
lighting network 10 may be provided in a space without significant
investment in new infrastructure.
[0149] The sensors included in each device 14 in the distributed
lighting network 10 may provide a very large amount of information
about the space in which they are located. Data from these sensors
may be utilized to gain insights about the space that were
previously unachievable, and thus add new and interesting features
to the distributed lighting network 10. This is due to the fact
that these sensors may be distributed throughout the space in a
relatively fine-grained fashion, and are capable of communicating
with one another and other remote devices 16. As discussed above,
the infrastructure afforded to lighting is especially suited for
this task.
[0150] In particular, providing an image sensor in each device 14
or a subset of devices 14 in the distributed lighting network 10
may provide extensive insights about a space. First and foremost,
however, an image sensor may be used to perform the function of
several other sensors, such as a PIR occupancy sensor and an
ambient light sensor. Certain aspects of detecting occupancy and
ambient light using an image sensor are discussed in copending U.S.
patent application Ser. No. 14/928,592, the contents of which are
hereby incorporated by reference in their entirety.
[0151] Detecting occupancy events using an image sensor may prove
especially challenging in some circumstances. Simply looking for
differences between pixel values in frames obtained from an image
sensor is inadequate, as there are many sources of noise that may
cause false occupancy event detections. For example, low-level
noise such as dark current, thermal noise, and analog-to-digital
conversion noise may be misinterpreted as motion and thus trigger
an occupancy event in some circumstances. Further, modulation of
light sources (e.g., fluorescent lights, pulse-width modulated
solid-state light sources, etc.) or sources of repetitive motion
such as the rotation of a fan or the sway of a tree branch in a
nearby window may be misinterpreted as an occupancy event. Changes
in ambient light, for example, due to cloud coverage or a change in
light output of one or more lighting fixtures may also be
misinterpreted as an occupancy event. For outdoor fixtures, rain,
snow, sleet, insects, and animals traversing a field of view of an
image sensor may be misinterpreted as an occupancy event.
Accordingly, FIGS. 33A and 33B illustrate a flow diagram
illustrating a method for detecting occupancy events using an image
sensor according to one embodiment of the present disclosure.
[0152] First, a frame counter (i) is set (step 1900). The frame
indicated by the frame counter is then obtained (step 1902). For
example, the frame may be obtained by requesting it from an image
sensor, or by viewing the frame as it is stored in memory. Next, a
zone counter (j) is set (step 1904). The zone indicated by the zone
counter in the frame indicated by the frame counter is then
obtained (step 1906). The zone may include pixel values for each
pixel within the zone. An average (e.g., a running average) of the
pixel change value for each pixel in the zone RAVGCPV.sub.Z is then
updated (step 1908). As discussed above, the pixel value (and thus
the pixel change value) may be a brightness value, a luma value, a
color value, raw pixel data (i.e., pixel data that has not been
processed e.g., via a demosaic process, referred to herein as a raw
value), or the like. An average of the pixel change value for the
zone AVGCPV.sub.Z may be calculated according to Equation (3):
AVGCPV Z = CPV P 1 + CPV P 2 + CPV PN NP Z ##EQU00001##
where AVGCPV.sub.Z is the average of the pixel change value for the
zone, CPV.sub.PX is the pixel change value for a particular pixel
within the zone (calculated as described below), and NP.sub.Z is
the number of pixels in the zone. The running average of the pixel
change value for the zone RAVGCL.sub.Z may then be calculated
according to Equation (4):
RAVGCPV.sub.Z=.alpha.AVGCPV.sub.ZCURR+.beta.RAVGCPV.sub.ZPREV
where RAVGCPV.sub.Z is the running average of the pixel change
value for the pixels in the zone, RAVGCPV.sub.ZCURR is the current
average of the pixel change value for the pixels in the zone,
RAVGCPV.sub.ZPREV is the previously calculated running average of
the pixel change value for the pixels in the zone, .alpha. is a
first blending factor, and .beta. is a second blending factor. The
updated running average of the pixel change value for the pixels in
the zone RAVGCPV.sub.Z is then stored (step 1910).
[0153] Next, a pixel counter (k) is set (step 1912). The pixel
indicated by the pixel counter in the zone indicated by the zone
counter in the frame indicated by the frame counter is then
obtained (step 1914). A running average of the pixel value for the
pixel RAVGPV.sub.P is then updated (step 1916). A running average
of the pixel value for the pixel RAVGPV.sub.P may be calculated
according to Equation (5):
RAVGPV.sub.P=.alpha.PV.sub.P+.beta.RAVGPV.sub.PPREV
where RAVGPV.sub.P is the running average of the pixel value for
the pixel, PV.sub.P is the pixel value of the pixel,
RAVGPV.sub.PPREV is the previously calculated running average of
the pixel value the pixel, a is a first blending factor, and .beta.
is a second blending factor. The running average of the pixel value
RAVGPV.sub.P is then stored (step 1918). An absolute difference
between the pixel value of the pixel PV.sub.P and the running
average of the pixel value of the pixel RAVGPV.sub.P is then
calculated (step 1920), the result of which is the pixel change
value. In some embodiments, this may be calculated based on the
previously calculated running average of the pixel value of the
pixel RAVGPV.sub.PPREV instead of the updated running average of
the pixel value RAVGPV.sub.P. This pixel change value is then
normalized by dividing the pixel change value by the running
average pixel change value for the zone RAVGCPV.sub.Z, and compared
to a threshold (step 1922). This essentially provides a Boolean
indicator for whether a change in a pixel value is reliably
significant and meaningful. If the difference between the pixel
value of the pixel PV.sub.P and the running average pixel value of
the pixel RAVGPV.sub.P divided by the running average of the pixel
change value for the zone RAVGCL.sub.Z is greater than a threshold,
a pixel change counter is incremented for the zone (step 1924). A
determination is then made whether the pixel change counter is
larger than half of the number of pixels in the zone (step 1926),
indicating that at least half of the pixels in the zone experienced
a significant change. Notably, any fraction of the pixels in the
zone may be used without departing from the principles of the
present disclosure (e.g., the determination may be whether the
pixel change counter is greater than at least a quarter of the
pixels in the zone, an eighth of the pixels in zone, or any other
fractional value of the pixels in the zone). If the pixel change
counter is larger than half the number of pixels in the zone, a
zone change flag is raised (step 1928), indicating that a reliably
significant change was detected in the zone. Notably, each zone may
be sized to detect an object at a desired size. For example, the
size of the zone may be around two times the size of an individual
in the field of view of the camera sensor so that half of the
pixels should indicate the detection of an object that is about
that size. The zone change flag may be an indication that the pixel
values for the pixels in the zone may need to be updated by
transmission to a remote device as discussed above. A determination
is then made whether the number of adjacent zone change flags for
the frame is above a threshold value (step 1930). If a number of
adjacent zone change flags is above a threshold value, this
indicates a change in pixel values over a large portion of the
frame, and is assumed to be a false alarm. Accordingly, the frame
is discarded (step 1932), the frame counter is incremented (step
1934), and the process returns to step 1902. In lieu of step 1930,
in some embodiments, if the determination made in step 1922 is
positive for a number of pixels in the frame over a threshold
value, the frame is similarly labeled a false detection and
discarded.
[0154] If the number of adjacent zone change flags in the frame is
not above the threshold, the zone counter is incremented (step
1936). A determination is then made whether the zone change counter
is greater than the number of zones in the frame (step 1938). If
the zone counter is greater than the number of zones in the frame,
a determination is made if the zone change flag(s) in a previous
frame (i-1) are within n zones of the zone change flag(s) in the
current frame (i) (step 1940). This indicates movement within the
frame, where n is a value chosen based on the framerate of the
image sensor such that the detected movement is occurring with a
velocity threshold for a desired object (e.g., the average moving
speed of a human, slow-moving vehicle, or the like). Generally, the
zone change flag(s) between frames should move at least one zone,
if not more to indicate movement between frames and thus avoid
false detections. Zone change flag(s) moving greater than n zones
are moving too fast to be an object that the image sensor is
interested in detecting and thus are ignored. If the zone change
flag(s) in a previous frame are within n zones of the zone change
flag(s) in the current frame, an occupancy event is detected (step
1942), the frame counter is incremented (step 1934), and the
process returns to step 1902. If the zone change flag(s) in a
previous frame are not within n zones of the zone change flag(s) in
the current frame, the frame counter is incremented (step 1934),
and the process returns to step 1902 without indicating an
occupancy event.
[0155] If the pixel change counter is not larger than half the
number of pixels in the zone, the pixel counter is incremented
(step 1944). A determination is then made whether the pixel counter
is greater than the number of pixels in the zone (step 1946). If
the pixel counter is not greater than the number of pixels in the
zone, the process returns to step 1914. If the pixel counter is
greater than the number of pixels in the zone, the process returns
to step 1936.
[0156] The above process has several advantages over conventional
image processing techniques directed towards object detection.
First, the running averages calculated above may be done so by
using the blending factors (rather than conventional running
average techniques), which may save processing power and memory
resources. Second, using the running average of the change of luma
in a zone, rather than at the pixel level further saves memory
resources by preventing the storage of a running change in luma
value for each pixel. In general, the above is a lightweight image
processing technique that may be used to detect occupancy events
using an image sensor. The image processing technique may be
capable of implementation on each individual device 14 including an
image sensor, such that an image sensor may provide occupancy event
detection in each device 14. Due to the fact that an image sensor
may further provide the functionality of other sensors as well,
such as ambient light sensors, using the image sensor in place of
these other sensors may save space and cost in the devices 14.
[0157] While PIR sensors and image sensors may be used alone to
detect occupancy events, additional sensor data may be used either
alone or in combination with the above to further increase the
accuracy of detection. For example, changes in atmospheric pressure
may correspond with an individual entering a space, and thus may be
used either alone or in combination with data from a PIR or image
sensor to detect an occupancy event. This may be especially true in
the case of a room with a door. The pressure in such a room will
significantly change upon open or close of said door, and thus
detecting such a change using an atmospheric pressure sensor may be
a simple way to detect when someone has entered or left the room
(corresponding with an occupancy event). Further, vibration and/or
motion detected from an accelerometer in a device 14 may be further
indicative of an occupancy event, and thus may be used alone or in
combination with data from a PIR or image sensor to detect an
occupancy event. Finally, sound detected from a microphone may be
indicative of an occupancy event, and may be used alone or in
combination with data from a PIR and/or image sensor to detect an
occupancy event. All of the data from the atmospheric pressure
sensors, the vibration and/or motion sensors, and the microphones
may be used according to the principles described above in order to
reduce background noise therein. That is, changes in a long-running
average of these sensor measurements may be much more indicative of
an event than instantaneous changes therein, and thus the
measurements may be examined in this manner in order to detect one
or more occupancy events. Changes in sound levels using the
microphone may be especially useful, as different changes may
correlate with different "degrees" of occupancy. That is, using
measurements from a microphone either alone or in combination with
data from a PIR and/or image sensor may allow for a rough estimate
of how many individuals are occupying and/or using a space, which
may provide additional insights about the space.
[0158] In one embodiment, an accelerometer is provided near an
image sensor in a device 14. Data from the accelerometer may then
be used to determine if the device 14 is moving. Such movement may
be likely to indicate, for example, that distortion will occur in
the output of the image sensor (e.g., from shaking, swaying, or the
like). In order to avoid false occupancy detections due to such
movement, the data from the accelerometer may be used in
conjunction with data from the image sensor, where occupancy events
detected by the image sensor are ignored or further processed with
the accelerometer indicates movement above a certain threshold.
[0159] As discussed above, certain distractors such as
precipitation, snow, insects, and animals may cause false
detections in outdoor devices 14. Often, these distractors are much
more likely to create a false occupancy event detection when they
are detected very near the image sensor. As insects and animals are
often attracted to light, this may occur frequently. Accordingly,
in one embodiment a lens associated with an image sensor on a
device 14 is configured with a focal length that is tailored to a
desired detection length from the image sensor. For example, the
minimum focal length of the lens may be at least 1 foot, at least 3
feet, at least 9 feet, and the like. Creating such a minimum focal
length causes objects that are near to the image sensor to remain
blurry, and thus reduces their detection by the image sensor. This
may avoid false detection of occupancy events due to these
distractors. In some cases, an integration time associated with the
image sensor may also be adjusted to "filter" out fast-moving
distractors such as precipitation, snow, insects, and animals.
Often, these distractors appear to be moving very quickly due to
their proximity to the image sensor and velocity. By increasing an
integration time of the image sensor to capture objects moving
within a desired range of velocities (e.g., human walking or
running speeds, the speed of slow-moving vehicles, etc.), faster
moving objects such as the above-mentioned distractors may
essentially be ignored by the image sensor, thereby avoiding false
detection of occupancy events.
[0160] The foregoing process for detecting an occupancy event with
an image sensor is merely illustrative, and not exhaustive. There
are many different ways to detect occupancy events using an image
sensor, all of which are contemplated herein. One problem with
detecting occupancy events with an image sensor is that there is a
minimum required level of light for doing so. That is, at light
levels below a certain threshold, the signal-to-noise ratio (SNR)
of an image sensor becomes too high to detect occupancy events.
Accordingly, FIG. 34 illustrates a method for adjusting the light
output of a lighting fixture 14A to maintain a necessary amount of
light for detecting occupancy events using an image sensor. Such
adjustment may be done with respect to an image sensor on the
lighting fixture 14A itself, or with respect to an image sensor on
any neighboring device(s) 14.
[0161] First, an occupancy timeout occurs (step 2000). As discussed
above, after an occupancy event is detected, an occupancy timeout
is initiated. As additional occupancy events are detected by a
device 14 or within a group, this occupancy timeout is re-initiated
such that the occupancy timeout starts over. When occupancy events
are not detected for a period of time, the occupancy timeout
occurs, indicating that the space is no longer occupied. The light
output of the lighting fixture 14A is then set to a predetermined
minimum level (step 2002). This predetermined minimum level may be
set up by a user or pre-programmed into the lighting fixture 14A.
The goal of the predetermined minimum level is to provide only the
necessary amount of light so that one or more nearby image sensors
may detect occupancy events. However, this light level may be
different for different image sensors, environmental conditions,
and the like. Accordingly, a determination is then made regarding
whether the SNR of any nearby image sensors is above a threshold
value (step 2004). If the SNR of the image sensors is above the
threshold value, the light output of the lighting fixture 14A is
decreased (step 2006) and the process is returned to step 2004. If
the SNR of the image sensor is below the threshold value, the light
output of the lighting fixture is increased (step 2008), and the
process again returns to step 2004. In this way, the light output
of the lighting fixture 14A is dynamically adjusted such that
nearby image sensors are capable of detecting occupancy while
avoiding over-lighting a space.
[0162] The above process may be conducted on each lighting fixture
14A in a group, in which case the lighting fixtures 14A may
cooperate to ensure that the light output levels thereof are
substantially uniform. In general, however, such minimum lighting
only needs to be done by lighting fixtures 14A that illuminate the
area near one or more entrances to a space. This is because it is
known that an individual will have to pass through an entrance to
initiate occupancy at any device 14. Accordingly, the foregoing
minimum dimming may only be done on those lighting fixtures 14A
that illuminate an area near an entrance to a space in order to
save energy and avoid over-lighting the space when it is not in
use.
[0163] Generally, the sensitivity of image sensors is such that the
minimum light level discussed above will be very low. Such light
levels may not be achievable by conventional power converter
circuitry used for solid state lighting devices, which generally
provide a pulse-width modulated current to a string or strings of
LEDs as discussed above. As the current required by a load becomes
small, the timing between current pulses in a pulse-width modulated
signal becomes very small, requiring a switching power converter
that is capable of very fast switching speeds. Such a switching
power converter may be impractical due to cost constraints, or
impossible altogether. Accordingly, FIG. 35 illustrates power
converter circuitry 26 for a lighting fixture 14A according to one
embodiment of the present disclosure. The power converter circuitry
26 includes low light output power converter circuitry 80 and
standard light output power converter circuitry 82. The low light
output power converter circuitry 80 and the standard light output
power converter circuitry 82 may each be coupled to an input
voltage (V.sub.IN), and coupled together at a number of outputs,
each of which are configured to power a different LED string. The
low light output power converter circuitry 80 may be configured to
provide a linear output signal, while the standard light output
power converter circuitry 82 may be configured to provide a
pulse-width modulated output signal. Accordingly, the low light
output power converter circuitry 80 may be a linear regulator,
while the standard light output power converter circuitry 82 may be
a switching power converter such as a buck converter, a boost
converter, a buck-boost converter, or the like. Notably, the low
light output power converter circuitry 80 may be less efficient
than the standard light output power converter circuitry 82 at
standard light levels, however, the difference in efficiency may be
negligible at the low light levels that the low light output power
converter circuitry 80 is used for. Further details of an ultra-low
dimming lighting fixture may be found in co-filed U.S. patent
application Ser. No. ______ filed Feb. 8, 2016 and titled "Solid
State Light Fixtures Having Ultra-Low Dimming Capabilities And
Related Driver Circuits And Methods", the disclosure of which is
hereby incorporated by reference in its entirety.
[0164] Another problem that may arise in detecting occupancy events
using an image sensor occurs when a neighboring lighting fixture
14A to a device 14 abruptly adjusts the light output thereof.
Neighboring devices 14 to the lighting fixture 14A may falsely
detect the changing light output as an occupancy event in some
circumstances, which may result in a control loop in which the
device 14 prevents the lighting fixture 14A from adjusting the
light output thereof as desired. This is a particular problem when
a lighting fixture 14A experiences an occupancy timeout event and
thus attempts to reduce the light output thereof, as nearby devices
14 may then detect this reduction in light output as an occupancy
event, causing the lighting fixture 14A to increase the light
output thereof. One way to compensate for this is for lighting
fixtures 14A to pre-announce when the light output thereof is going
to change, so that nearby devices 14 can ignore said changes. For
example, nearby devices 14 may ignore occupancy events detected by
an image sensor associated therewith for a period of time after
such announcement. However, this may be undesirable in some
circumstances, as these devices 14 may then fail to detect the
occurrence of an actual occupancy event. Accordingly, in some
embodiments nearby devices 14 may ignore only a portion of a field
of view of an image sensor associated therewith, and specifically
that portion that is affected by the light output of the
neighboring lighting fixture 14A. For example, a frame of an image
from an image sensor may be divided into a number of zones, and
only those zones that are affected by the neighboring lighting
fixture 14A (which may be determined, for example, during the
automatic grouping process discussed above) may be ignored.
However, even this may result in missed occupancy event
detections.
[0165] Accordingly, in some embodiments the amount of light change
from the neighboring lighting fixture 14A, which may be
predetermined during the automatic grouping process or determined
based on communication with the lighting fixture 14A may be taken
into account and ignored, while other changes detected by the image
sensor according to the processes described above may continue to
function. In other words, the automatic grouping process discussed
above may indicate that a neighboring lighting fixture 14A is
detected at a certain intensity by the device 14. The device 14 may
then ignore changes in light output detected by the image sensor
associated therewith within this range. This allows for the
continuing detection of occupancy events while failing to falsely
detect occupancy events based on the changing light output of
neighboring lighting fixtures 14A.
[0166] Yet another, simpler way to avoid the above mentioned
problems is to dim the light output of neighboring lighting
fixtures 14A slowly upon the occurrence of an occupancy timeout. If
done slowly enough, this prevents nearby devices 14 from falsely
interpreting the changing light output from nearby lighting
fixtures 14A as an occupancy event and thus avoids the control loop
problems discussed above. Generally, it is not critical to
instantly reduce the light output in a space on the occurrence of
an occupancy timeout. Accordingly, the above method is a simple but
effective way to avoid entering undesirable control loops between
neighboring devices 14 using image sensors to detect occupancy
events.
[0167] It may be desirable for the image sensor to be capable of
detecting a commissioning tool used in the distributed lighting
network 10 to communicate with the various devices 14. Details
regarding the initiation of communication between a device 14 and a
commissioning tool are discussed in detail in U.S. patent
application Ser. No. 13/782,022, the disclosure of which is hereby
incorporated by reference in its entirety. In short, the
commissioning tool includes a light emitting device of a certain
color, which must be detected by a device 14 to ensure that the
commissioning tool is attempting to communicate specifically with
that device 14. If the light emitting device were not present on
the commissioning tool, messages sent, for example, via a wireless
signal, could be received and acted upon by any number of nearby
devices 14. Previously, light from the commissioning tool was
detected by an ambient light sensor in a device 14. However, as
discussed above it may be desirable to replace the functionality of
a dedicated ambient light sensor with an image sensor. Accordingly,
FIG. 36 is a flow diagram illustrating a method of detecting a
commissioning tool using an image sensor according to one
embodiment of the present disclosure.
[0168] Upon initiation of the detection process, which may be in
response to a wireless signal provided by the commissioning tool
indicating that it wishes to communicate with a nearby device 14,
the gain of the image sensor is first zeroed for any undesired
colors (step 2100). Specifically, the gain of the image sensor is
zeroed for all colors except the color of the light emitting device
on the commissioning tool. If the commissioning tool is in the
field of view of the image sensor, the resulting image will include
a highly saturated area where the light emitting device of the
commissioning tool is located due to the gain zeroing. Accordingly,
the integration time of the image sensor is then adjusted such that
the brightest object in the frame (which should be the light
emitting device of the commissioning tool) is below saturation
(step 2102). The frame is then windowed to the bounds of the
brightest object, which, once again, is the light emitting device
of the commissioning tool (step 2104). This windowing allows the
image sensor to reduce the amount of data that it needs to collect,
and therefore may enable the frame rate of the image sensor to be
increased (step 2106). This is important, as the light provided by
the commissioning tool may be modulated at a particular frequency
to prevent false detections of other light emitting devices during
this process. To assure that the modulation frequency of the light
provided by the commissioning tool is different from standard
sources of interference, the light signal may be modulated at a
frequency above 60 Hz (e.g., 80 Hz). Many image sensors are
incapable of providing frame rates capable of detecting modulation
at this frequency. The dynamic windowing around the light provided
from the commissioning tool may remedy this, as the frame rate of
the image sensor is proportional to the area sampled thereby in
many cases. A number of frames from the image sensor are then
sampled (step 2108), and it is determined if the sampled frames are
modulated at a desired detection frequency (i.e., the modulation
frequency of the light provided by the commissioning tool) (step
2110). This may be done, for example, by looking for a beat
frequency which is the difference of the sample frequency of the
image sensor and the modulation frequency of the light provided by
the commissioning tool. If the modulation is detected, the device
14 will respond to the commissioning tool (step 2112). If the
modulation is not detected, the device may cease searching for the
commissioning tool (step 2114).
[0169] While image sensors may be used to implement the
functionality previously served by other sensors, they may also be
used to implement new functionality in the distributed lighting
network 10. One such function is security, wherein the image
sensors may be used not only to detect occupancy events and ambient
light levels, but also to provide images of a space to a central
location for security purposes. In many wireless lighting networks
12A, such functionality may be problematic, as the mesh networks
used by the devices 14 therein may not be suited for the transfer
of high bandwidth data such as images and video. Certain
compression techniques may be used to circumvent this effect, such
as only sending images and/or video when something in the frame has
changed, using well-known video compression codecs such as MPEG-4
and H.264, or the like. However, in some situations even this may
be insufficient to overcome these shortcomings. Accordingly, one or
more of the devices 14 in the network may communicate this image
and/or video data over a secondary communications means that is
better suited for these tasks. For example, one or more of the
devices 14 may connect to a WiFi network or other high-speed
wireless communications network in order to provide images and/or
video from image sensors in the devices 14 to a desired
location.
[0170] While images and/or video of a space are useful when viewed
separately, it may be more advantageous to provide a unified visual
representation of a space in some cases. For example, images from
multiple devices 14 in the distributed lighting network 10 may be
merged together at their points of overlap to present a unified
overhead view of the space. This image may be very high resolution,
as it combines the resolution of each of its constituent images.
Such an image and/or video stream may be viewed together and thus
provide an excellent overview of what is happening within the space
at any given time.
[0171] FIG. 37 is a flow diagram describing a method for providing
such a merged image. First, images from multiple image sensors are
provided (step 2200). The images are then processed (step 2202).
The processing may include not only merging the images at their
points of overlap, but also de-warping, de-skewing, and otherwise
compensating the images for any distortion therein. A merged image
is then provided (step 2204). A determination is then made
regarding whether a change has been detected from any of the image
sensors (step 2206). If a change has been detected, new images are
obtained from the image sensors (step 2208), and the process
returns to step 2202 to process these images and provide the merged
image once again. If no changes have been detected by the image
sensors, the merged image continues to be provided as in step 2204.
This prevents the unnecessary use of bandwidth in the network, as
it only requires updated images when something in the space has
changed.
[0172] In addition to the above, it may also be highly advantageous
to correlate image data from one or more image sensors with
geospatial data obtained from one or more other sensors.
Correlating image data with geospatial data allows for a real-space
representation of a space to be constructed, which may be highly
useful in many situations. Such a process may be referred to as
georegistration of image data, and a flow chart describing the
basics of such is shown in FIG. 38. First, geospatial data from one
or more sensors and image data from one or more image sensors is
provided (step 2300). The image data and the geospatial data are
then correlated (step 2302). Generally, if two points of image data
(e.g., pixels or areas) can be correlated with two points of
geospatial information (e.g., latitude and longitude, GPS
coordinates, etc.), the image data can be considered georegistered
and a real-space representation of the space can be generated.
Next, image data may be presented based on the correlation of image
data and geospatial data (step 2304). This may involve presenting
the image data such that it is properly oriented, properly scaled,
or the like. Further, the image data may be displayed with
geospatial information overlayed thereon (step 2306), which may
provide additional context to the image data. Further applications
of an image sensor in one or more devices 14 in the distributed
lighting network 10 are discussed below.
[0173] In some situations, power consumption may be an important
concern for the devices 14 in the distributed lighting network 10.
For example, power consumption may be very important in emergency
situations in which one or more of the devices 14 is powered by a
battery backup, or in off-grid applications in which an off-grid
energy source is used to charge a battery, which in turn powers one
or more of the devices 14. As discussed above, current solid-state
lighting fixtures 14A provide a pulse-width modulated current to
one or more LEDs in order to provide a desired light output. This
pulse-width modulated current is fixed in magnitude with a
modulated duty cycle. The duty cycle thus determines the light
output of the lighting fixture 14A. In some situations, the
efficiency of driving one or more LEDs may be improved.
[0174] FIG. 39 is a flow diagram illustrating a method for
controlling the brightness of one or more LEDs according to one
embodiment of the present disclosure. First, a determination is
made regarding whether the brightness of the LEDs is being adjusted
up or down (step 2400). If the brightness is being adjusted up, a
determination is then made regarding whether a pulse magnitude of a
pulse-width modulated signal provided to the LEDs is less than a
predetermined maximum pulse magnitude (step 2402). If the pulse
magnitude of the pulse-width modulated signal is less than the
maximum pulse magnitude, the magnitude of the pulse-width modulated
signal is increased (step 2404). If the pulse magnitude of the
pulse-width modulated signal is not less than the maximum pulse
magnitude, the duty cycle of the pulse-width modulated signal is
increased (step 2406). If the brightness of the LEDs is being
adjusted down, a determination is then made regarding whether a
pulse magnitude of the pulse-width modulated signal is greater than
a predetermined minimum magnitude (step 2408). If the pulse
magnitude of the pulse-width modulated signal is greater than the
minimum magnitude, the pulse magnitude of the pulse-width modulated
signal is decreased (step 2410). If the pulse magnitude of the
pulse-width modulated signal is not greater than the minimum
magnitude, the duty cycle of the pulse-width modulated signal is
decreased (step 2412).
[0175] FIG. 40 shows an exemplary pulse-width modulated signal
according to one embodiment of the present disclosure. In
particular, FIG. 40 shows a pulse width P.sub.W, a pulse magnitude
P.sub.m, a minimum pulse magnitude P.sub.mmin and a maximum pulse
magnitude P.sub.mmax. When adjusted according to the process
discussed above, efficiency improvements may be achieved over
conventional fixed magnitude pulse-width modulation schemes for
solid-state lighting devices. The minimum pulse magnitude
P.sub.mmin may be chosen such that the light output of the lighting
fixture 14A maintains one or more desired parameters such as
brightness, color, color temperature, color rendering index, or the
like. However, in some embodiments one or more of these parameters
may be sacrificed in favor of efficiency. At a certain pulse
magnitude P.sub.m, one or more of the desired parameters for light
output mentioned above will begin to suffer. While this is
generally not desirable, it may be a useful tradeoff in some cases
where any quality of light is better than none. Additional actions
such as driving only the most efficient LEDs in the lighting
fixture 14A or intentionally sacrificing light output parameters
such as color rendering index may be simultaneously used along with
the power control process discussed above to obtain even further
improvements in efficiency at the expense of light output
quality.
[0176] In situations such as the aforementioned emergency and
off-grid applications, it may be advantageous to know with
precision the power consumption of a device 14 in the distributed
lighting network 10. Accordingly, FIG. 41 is a flow diagram
illustrating a method for calibrating a power consumption
measurement of a device 14 according to one embodiment of the
present disclosure. Such a calibration process may occur, for
example, after assembly. First, if the device 14 is a lighting
fixture 14A, the LED array 24 is turned off (step 2500). If the
device 14 is not a lighting fixture 14A, there is no LED array 24
to turn off, and thus this step may be skipped. The standby power
consumption of the device 14 is then measured (step 2502) and
stored (step 2504). Once again, if the device 14 is a lighting
fixture 14A, the LED array is turned on (step (2506). An active
power consumption of the device 14 is then measured (step 2508) and
stored (step 2510). In devices 14 other than lighting fixtures 14A,
these steps may not be performed, as they may not be necessary. The
stored power consumption values may be used to more accurately
determine the instantaneous or historical power consumption of the
device 14. Such measurements may increase the accuracy of power
consumption of the devices 14 such that power metering can be
performed by one or more of the devices 14 in the distributed
lighting network 10.
[0177] One use for the aforementioned power consumption data is in
PoE devices 14 in the distributed lighting network 10. PoE devices
14 are capable of requesting a given amount of power from a switch
14E. Generally, PoE devices 14 are configured to request an amount
of power that is equal to the maximum possible power draw of the
device 14. However, the device 14 may rarely consume this much
power. Accordingly, FIG. 42 is a flow diagram illustrating a method
of requesting power from a switch 14E in order to improve the
efficiency thereof. First, the power consumption of a device 14 is
determined (step 2600). An updated request for power is then sent
from the device 14 to a switch 14E (step 2602). The updated request
is based on the determined actual power consumption of the device
14, which may be instantaneously updated, averaged and updated
periodically, or updated in any other way. A determination is then
made regarding whether the power consumption of the device 14 has
changed (step 2604). If the power consumption of the device 14 has
changed, the process starts again at step 2600. If the power
consumption of the device 14 has not changed, the process starts
again at step 2604. Requesting only the power that is
instantaneously required by a device 14 may significantly improve
the efficiency of the wired lighting network 12B, as each switch
14E no longer has to deliver power to each device 14 based on the
maximum possible power requirements of that device.
[0178] The foregoing power saving techniques may be especially
useful in off-grid lighting fixtures 14A, the details of which are
illustrated in FIGS. 43A and 43B. As shown in the Figures, an
off-grid lighting fixture 14A includes a body 84, a light source
86, a battery 88, and a photovoltaic panel 90. The body 84 houses
the light source 86, and further includes the driver circuitry 22
and other necessary components of the lighting fixture 14A. The
battery 88 is located on top of the body 84, and in particular may
be fused with the body 84. Further, the photovoltaic panel 90 is
located on top of the battery 88. Notably, the photovoltaic panel
90, the battery 88, and the light source 86 are located directly
adjacent to one another. This is so that energy generated by the
photovoltaic panel 90 and provided by the battery 88 are maximized,
and efficiency is not degraded in the transport of said energy to
the light source 86. Notably, FIGS. 43A and 43B are merely
exemplary embodiments of an off-grid lighting fixture 14A. Numerous
different configurations may exist for the body 84, the battery 88,
and the photovoltaic panel 90, all of which are contemplated
herein.
[0179] FIG. 44 is a block diagram illustrating details of the
operational circuitry of the off-grid lighting fixture 14A
according to one embodiment of the present disclosure. The off-grid
lighting fixture 14A shown in FIG. 44 is substantially similar to
the lighting fixture 14A discussed above with respect to FIG. 2,
except that the input voltage source is replaced with an off-grid
power source 92 and a battery 94. The off-grid power source may be
any suitable off-grid power source, and may be a renewable energy
source such as a photovoltaic panel or a wind turbine. The off-grid
power source 92 charges the battery 94, which in turn provides the
necessary power for the driver circuitry 22.
[0180] FIG. 45 is a block diagram illustrating details of the
operational circuitry of the off-grid lighting fixture 14A
according to an additional embodiment of the present disclosure.
The off-grid lighting fixture 14A shown in FIG. 45 is substantially
similar to that discussed above with respect to FIG. 4, except that
the input voltage source is replaced with an off-grid power source
92 and a battery 94. The off-grid power source 92 may be any
suitable off-grid power source, and may be a renewable energy
source such as a photovoltaic panel or a wind turbine. The off-grid
power source 92 charges the battery 94, which in turn provides the
necessary power for the driver circuitry 22.
[0181] The intelligence of the off-grid lighting fixture 14A may be
especially useful in off-grid applications. In addition to merely
providing light, the off-grid lighting fixture 14A may measure
environmental parameters, provide security, and the like. Further,
a number of off-grid lighting fixtures 14A may form the distributed
lighting network 10, which may be used for communication, and
further may distribute wireless or wired communications signals
received from other sources. For example, an off-grid lighting
fixture 14A may act as a base-station for cellular signals in some
embodiments. In general, the intelligence of the off-grid lighting
fixture 14A may significantly enhance its utility as an off-grid
device.
[0182] In some situations, due to communications network restraints
and other factors it may be desirable to communicate information
with one or more devices 14 in the distributed lighting network 10
via optical means. For example, lighting fixtures 14A that are
mounted very high in a warehouse in which wired or wireless
communications are not possible may need to be configured. One
example of such a fixture is described in co-filed U.S. patent
application Ser. No. ______ filed Feb. 8, 2016 and titled "Led
Luminaire Having Enhanced Thermal Management", the disclosure of
which is hereby incorporated by reference in its entirety.
Conventionally, an individual would have to climb a ladder or
otherwise access each lighting fixture 14A in the distributed
lighting network 10 in this situation in order to perform such
configuration. If each device 14 is equipped with an image sensor,
however, such configuration may be significantly simplified. FIG.
46 shows an example of such configuration. As shown in FIG. 46, an
optically encoded medium (e.g., a barcode, a QR code, or even a
particular color or array of colors) may be presented within a
field of view of an image sensor within a lighting fixture 14A. The
image sensor in the lighting fixture 14A may read the information
from the optically encoded medium and adjust one or more settings
based thereon.
[0183] FIG. 47 is a flow diagram illustrating a method for changing
one or more settings of a device 14 based on one or more optical
indicators. First, the environment is scanned for optical
indicators (step 2700). As discussed above, this is likely
performed by an image sensor, however, any suitable means for
finding optical indicators in the surrounding environment may be
used without departing from the principles of the present
disclosure. A determination is then made whether an optical
indicator has been found (step 2702). If an optical indicator has
been found, one or more settings of the device 14 are adjusted
based on the optical indicator (step 2704). If an optical indicator
has not been found, the process returns to step 2700 where the
environment is scanned for optical indicators. Using the process
described above, settings for devices 14 that are otherwise
inaccessible via wired or wireless communications means and
difficult to physically access may be changed easily.
[0184] As discussed above, providing a number of different sensors
on devices 14 that are distributed throughout a space has
enumerable benefits. In general, the sensor data obtained from
these devices is highly valuable because of the nature of a
distributed lighting network 10. Lighting fixtures 14A enjoy a
relatively widespread pre-existing infrastructure of power.
Further, lighting fixtures 14A are generally distributed relatively
evenly and consistently throughout a space. By providing lighting
fixtures 14A and other devices 14 that capitalize on these
attributes, a large network of sensors that are distributed
throughout a space can be achieved. Such a network of sensors may
provide an immense amount of information about a space, and may be
used to provide significant advances in the functionality of a
space.
[0185] A general framework for utilizing the sensor data obtained
in the distributed lighting network 10 is shown in FIG. 48. First,
sensor data from one or more devices 14 in the network is obtained
(step 2800). The sensor data is then analyzed (step 2802). This
analysis may comprise any number of different signal processing
and/or analysis techniques, some examples of which are provided
below. One or more environmental conditions are then determined
from the analyzed sensor data (step 2804). Some examples of these
environmental conditions are discussed in detail below. A
determination is then made whether the sensor data has changed
(step 2806). If the sensor data has changed, the sensor data is
analyzed again at step 2802 and one or more environmental
conditions are determined again at step 2804. This process may
repeat periodically or persistently, and the determined
environmental conditions may be used in any number of ways to
improve the management of a space or gain insights about the use
thereof. If the sensor data has not changed, the process waits for
the sensor data to change.
[0186] For example, FIG. 49 shows a similar process to that shown
in FIG. 48 wherein the sensor data is used to adjust one or more
parameters of a building management system. First, sensor data from
one or more devices 14 in the network is obtained (step 2900). The
sensor data is then analyzed (step 2902), and the analyzed sensor
data is used to adjust one or more parameters of a building
management system (step 2904). For example, the sensor data may be
used to adjust a temperature of a thermostat, the amount of fresh
circulating air into a space, or the like. A determination is then
made regarding whether the sensor data has changed (step 2906). If
the sensor data has changed, the sensor data is analyzed again at
step 2902 and the one or more building management system parameters
are adjusted at step 2904. If the sensor data has not changed, the
process waits for the sensor data to change.
[0187] Examples of environmental conditions and their uses are
discussed below. With regards to an ALS, such a sensor may be used
as discussed above to detect ambient light levels in a space. One
or more lighting fixtures 14A may then change the light output
thereof in order to maintain a consistent amount of light on a task
surface below the lighting fixture(s) 14A. Further, an ALS may be
used to detect a modulating light signal in order to participate in
the automatic grouping process discussed above and/or to decode
data in a modulated light signal. Additionally, ALS measurements
obtained from multiple devices 14 in the distributed lighting
network 10 may be used to determine a "sun load" of a space. That
is, ALS measurements obtained from multiple devices 14 in the
distributed lighting network 10 may detect the amount of sunlight
in a given space. This information may be used to predictively
adjust one or more heating or cooling parameters in order to more
accurately heat and/or cool a space. Further, such information may
be used to adjust automated blinds and/or smart windows in order to
adjust the amount of sunlight entering a space. Since current
methods of heating and/or cooling by taking temperature
measurements at a number of different thermostats located
throughout a space may result in a wide temperature swing within a
given space, such information may allow the temperature of a space
to be more accurately maintained and thus maintain a more
comfortable environment.
[0188] Regarding an accelerometer or other motion sensor, this
sensor data may be used to detect occupancy as discussed above.
Further, an accelerometer or other motion sensor may be used to
detect whether a device 14 is properly oriented (e.g., whether a
pole-mounted device 14 is leaning or otherwise improperly mounted).
The same orientation information may be used to determine if a
device 14 is moving (e.g., swaying), and thus may be used, in the
case of devices 14 that are outdoors, to detect wind speed,
earthquakes, and structural stability. The sway of a device 14 that
is located outside may be directly correlated with the wind speed,
and thus such information may be obtained from an accelerometer or
other motion sensor. Measuring seismic activity via a distributed
network of devices 14 may prove immensely valuable, since the
devices 14 are relatively close together and thus may provide
valuable insights about the fine-grained distribution of seismic
activity. Such information may be used to predict earthquakes or
other seismic activity in the future. When placed on a structure
such as a bridge, devices 14 may provide valuable insight regarding
the structural integrity of the structure, for example, by
examining resonant vibration patterns of the structure. Such
information may be used to provide alerts if a structure becomes
dangerously unstable or may be used to dictate required maintenance
of a structure over time.
[0189] Regarding an image sensor, such a sensor may be used to
detect occupancy events and ambient light levels as discussed
above. Further, the flexibility of an image sensor may be used to
analyze traffic (e.g., human traffic in an indoor space, automobile
traffic in an outdoor space, and high-traffic lanes on a factory
floor), may be used to determine empty parking spots in a parking
garage, may be used to determine waiting times (e.g., length of
register lines), and may be used to differentiate between customers
and associates in a retail establishment in order to match
associates with customers that need assistance. As image processing
techniques continue to improve, the information about a space that
may be obtained is virtually endless. Examples of using an image
sensor to analyze a space are included in U.S. patent application
Ser. No. 14/827,007, the disclosure of which is hereby incorporated
by reference in its entirety.
[0190] Other types of image sensors may provide additional data
that may be used in the distributed lighting network 10. For
example, low-resolution IR imaging (e.g., forward looking infrared
imaging sensors) may be used to increase the efficacy of occupancy
detection, may be used to detect fires, may be used to detect
hot-spots in a space for HVAC control purposes, may be used to
predict maintenance on machines in a factory (e.g., by detecting
changes in the normal temperature signatures thereof), and the
like. Further, time of flight (TOF) imaging sensors may be used to
construct three-dimensional representations of a space, which may
be used for building reconstruction and/or modeling.
[0191] Regarding temperature and humidity sensors, such sensors may
be used to provide more fine-grained information to an HVAC system
controlled by a BMS, which may use the information to better
control the environmental conditions in a space. In outdoor
applications, temperature and humidity sensors may provide
fine-grained temperature measurements that may not only give an
accurate representation of the weather, but may also be used to
predict future weather conditions. Additional sensors such as wind
speed sensors and the like may be used to further increase the
information available to outdoor devices 14. Since outdoor devices
14 may be distributed in large numbers throughout a space, weather
patterns that were previously undetectable may become apparent and
increase the accuracy of weather forecasting.
[0192] Regarding barometers or other atmospheric pressure sensors,
such sensors may be used to differentiate between floors of a
building as discussed above in order to facilitate network
formation, may be used to detect occupancy either alone or in
combination with one or more other sensors, and may be used to
determine or predict the weather as discussed above.
[0193] Regarding air quality sensors such as carbon dioxide
sensors, carbon monoxide sensors, VOC sensors, and smoke sensors,
such sensors may be used to provide an accurate representation of
the air quality in a space. This information may be used to
circulate fresh air into a space via a building management system,
or may be used to identify dangerous conditions that require
evacuation or other corrective measures. Alarms and alerts may be
provided as necessary based on the sensor measurements.
[0194] Regarding spatial sensors such as GPS sensors and
magnetometers, measurements from these sensors may be used for
georegistration of devices 14 and/or the images therefrom, may
provide a synchronized clock (GPS), and may provide an orientation
of a device. In general, spatial sensors may be used to identify
the precise location of a device 14. This location information may
be shared with other devices 14, including remote devices 16. Since
devices 14 in the distributed lighting network 10 will generally
remain stationary, a very accurate location may be obtained based
on measurements from spatial sensors. This location information may
be much more accurate, for example, than location information
obtained from a mobile remote device 16, and thus may be shared
with said remote device 16. In other cases, one or more remote
devices 16 may not have access to location information and thus may
obtain it from one or more devices 14 in the distributed lighting
network 10.
[0195] Regarding ultrasonic sensors, such sensors may be used to
"image" an environment in a three-dimensional manner, and further
may assist in object detection and occupancy event detection.
[0196] Regarding microphones and/or speakers, measurements from
these devices may be used to detect occupancy events as described
above. Further, measurements from these devices may be used to
detect auditory events (e.g., clapping), which may be used to
control one or more devices 14 in the distributed lighting network
10, and may be used to identify events (e.g., shots fired,
screaming, shouting, or the like). Event classification based on
detected sound may be performed by each device 14 in a lightweight
manner or analyzed in detail by a remote device 16. Providing a
microphone and speaker in each device 14 in the distributed
lighting network 10 also allows for the detection and analysis of
voice commands, which may simplify the control and operation of the
distributed lighting network 10, and may allow for the delivery of
audio media (e.g., music, radio, podcasts, or the like) to devices
14 throughout the distributed lighting network 10 as desired.
[0197] In some embodiments, the communications circuitry of a
device 14 may include Bluetooth communications circuitry. Such
communications circuitry may allow the device 14 to pair with one
or more mobile devices, for example, to make calls, play music, or
simply detect when a mobile device is nearby. Further, the
communications circuitry may include radio frequency identification
(RFID) receiver and/or transmitter circuitry. Accordingly, one or
more devices 14 may detect, for example, an RFID tag in a badge or
key fob and grant or deny access to a particular space based
thereon.
[0198] The analysis discussed above with respect to the various
sensor measurements may be performed locally by each device 14 in
the distributed lighting network 10, may be performed in a
distributed manner throughout the distributed lighting network 10,
may be performed by a single device 14 such as a border router 14D,
or may be performed by a remote device 16. Using a remote device 16
to analyze sensor data from the various devices 14 in the
distributed lighting network 10 may allow for extensive analysis
using techniques such as deep machine learning, artificial
intelligence, and the like. As discussed above, one or more border
routers 14D may facilitate the retrieval of sensor data from each
device 14, for example, via an API with which a remote device 16
interfaces.
[0199] One notable feature that may be facilitated by the inclusion
of microphones and speakers in the devices 14 of the distributed
lighting network 10 is discussed with respect to FIGS. 50 and 42.
Specifically, FIG. 50 illustrates an intra-network communication
process, while FIG. 51 illustrates an inter-network communication
process. First, network communication is initiated (step 3000).
Such communication may be initiated, for example, by a voice
command (e.g., "Call John"), or by any other suitable means. A
network end point is then determined for the communication (step
3002). This may be accomplished, for example, by a look-up table
regarding the location of the individual with whom communication
was requested, may involve the use of one or more sensors to locate
an individual, or may be accomplished by any other suitable means.
A communication channel is then opened with the end point (step
3004). For example, bidirectional voice communication may be
initiated with the network end point and the initiating device
14.
[0200] FIG. 51 illustrates a similar process for inter-network
communication. First, network communication is initiated (step
3100). A network end point is then determined for the communication
(step 3102). A communication channel is then opened with the end
point, which is a remote device 16 (step 3104). Notably, this
communication is routed through an external network, which is
facilitated by a border router 14D. In one embodiment, the remote
device 16 is a wireless communications device, and thus
communication is initiated through a cellular network. Using the
processes outlined above, communication may be initiated with
individuals in or outside the distributed lighting network 10 in a
convenient manner.
[0201] As discussed above, devices 14 in the distributed lighting
network 10 may use sensor data to calibrate or otherwise change
their behavior over time. For example, devices 14 in the
distributed lighting network 10 may automatically group with one
another, or may adjust calibration thresholds based on historical
data in order to increase the accuracy of event detection and
response. Accordingly, it may be desirable in some circumstances to
leverage the calibration that has been accomplished by a set of
devices 14 for a different set of devices 14 in the distributed
lighting network 10. For example, devices 14 that have been
installed and running for a period of time may include calibration
information that is useful for newly installed devices 14.
Accordingly, FIG. 52 is a flow diagram illustrating a method of
copying device settings from one device 14 or group of devices 14
to another device 14 or group of devices 14 in the distributed
lighting network 10. First, device settings are obtained from a
desired set of devices 14 (step 3200) and stored (step 3202). The
device settings are then transferred to a set of different desired
devices 14 (step 3204). These settings are then implemented on the
different desired devices 14 (step 3206). Copying settings in this
manner may allow newly installed devices 14 the benefit of the
automatic calibration performed by devices 14 that have been up and
running for a period of time, and thus may reduce the period of
time newly installed devices 14 need for calibration.
[0202] FIGS. 53A and 53B illustrate an exemplary lighting fixture
14A that may be used in an indoor setting according to one
embodiment of the present disclosure. The lighting fixture 14A
includes a lens 96 and a square or rectangular outer frame 98. The
lens 96 is coupled to and extends between opposite sides of the
outer frame 98, and may be substantially arc-shaped, such that an
outer surface of the lighting fixture 14A appears as a half-circle.
Further, the lens 96 may include a sensor module cover 96A, which
is a portion of the lens 96 that is removable in order to provide
access to a sensor module connector and space for a sensor module
14B to be connected to the lighting fixture 14A. The outer frame
may optionally be surrounded by a shroud 98A, which gives the light
a troffer-style appearance and may provide additional mounting
options for the lighting fixture 14A, as shown in FIG. 53B.
Further, the outer frame 98 may include a number of flat mounting
surfaces 98B, which extend outwards and include one or more
mounting holes for mounting the lighting fixture 14A, for example,
to a ceiling.
[0203] Those skilled in the art will recognize improvements and
modifications to the preferred embodiments of the present
disclosure. All such improvements and modifications are considered
within the scope of the concepts disclosed herein and the claims
that follow.
* * * * *
References