U.S. patent application number 14/332832 was filed with the patent office on 2014-11-06 for occupancy sensor.
The applicant listed for this patent is Healthsense, Inc.. Invention is credited to David T. Anderson, Brian J. Bischoff, John L. Ryan.
Application Number | 20140326072 14/332832 |
Document ID | / |
Family ID | 44630432 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140326072 |
Kind Code |
A1 |
Anderson; David T. ; et
al. |
November 6, 2014 |
OCCUPANCY SENSOR
Abstract
Embodiments of the present disclosure relate to methods,
devices, and systems for determining occupancy of a user. One
method to determine occupancy of a user includes sensing a change
in resistance of a sensor element of an occupancy sensor,
correlating the change in resistance to a force transmitted to the
occupancy sensor, and determining an occupancy status of a user
based on the force transmitted.
Inventors: |
Anderson; David T.;
(Hamburg, MN) ; Bischoff; Brian J.; (Red Wing,
MN) ; Ryan; John L.; (Maple Grove, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Healthsense, Inc. |
Mendota Heights |
MN |
US |
|
|
Family ID: |
44630432 |
Appl. No.: |
14/332832 |
Filed: |
July 16, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13183224 |
Jul 14, 2011 |
8783114 |
|
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14332832 |
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61364255 |
Jul 14, 2010 |
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Current U.S.
Class: |
73/774 |
Current CPC
Class: |
G01L 1/2218 20130101;
G08B 21/0415 20130101; A61G 2203/32 20130101; G08B 21/0461
20130101; G01L 1/22 20130101; G01G 19/445 20130101 |
Class at
Publication: |
73/774 |
International
Class: |
G01L 1/22 20060101
G01L001/22 |
Claims
1. A method for determining occupancy of a user, comprising:
sensing a change in resistance of a sensor element of an occupancy
sensor; correlating the change in resistance to a force transmitted
to the occupancy sensor; and determining an occupancy status of a
user based on the force transmitted.
2. The method of claim 1, wherein the method includes transmitting
a force to the occupancy sensor via an activation bar coupled to
the occupancy sensor.
3. The method of claim 1, wherein the method includes correlating
the change in resistance to a force transmitted to the occupancy
sensor by converting the change in resistance to a voltage that
correlates to the force transmitted.
4. The method of claim 1, wherein the method further includes
calibrating an unloaded threshold and a loaded threshold of the
sensor element by sensing the resistance of the sensor element and
determining a force transmitted to the sensor element without a
user transmitting force to the sensor element.
5. The method of claim 4, wherein the method include determining an
unoccupied status of the user when the sensing element resistance
is at or above the unloaded threshold.
6. The method of claim 4, wherein the method include determining an
occupied status of the user when the sensing element resistance is
below the loaded threshold and has not exceeded the unloaded
threshold.
7. The method of claim 4, wherein the method include determining an
occupied status of the user when the sensing element resistance is
below the unloaded threshold for a period of time.
8. An occupancy sensor, comprising: a sensing element; wherein a
resistance of the sensing element is dependent on a force exerted
on the sensing element an activator bar, wherein the activator bar
transmits the force to the sensing element; and a module, wherein
the module senses the resistance of the sensing element and
converts the resistance to a corresponding voltage.
9. The occupancy sensor of claim 8, wherein a cable connector
couples the sensing element to the module.
10. The occupancy sensor of claim 8, wherein the module includes
circuitry to sense the resistance of the sensing element and
convert the resistance of the sensing element to the corresponding
voltage.
11. The occupancy sensor of claim 8, wherein an edge support
surrounds the activator bar.
12. The occupancy sensor of claim 8, wherein the sensor element is
coupled to a base and the activator bar is placed over the sensor
element and coupled to the base.
13. The occupancy sensor of claim 8, wherein the bed occupancy
sensor includes a number of fasteners to couple the bed occupancy
sensor to a bed structure.
14. A system for determining occupancy of a user, comprising: a
support structure, wherein a static object is placed on the support
structure; and an occupancy sensor, wherein the occupancy sensor
includes: a sensing element; wherein a resistance of the sensing
element is dependent on a force exerted on the sensing element; and
a module, wherein the module senses the resistance of the sensing
element and converts the sensed resistance to a voltage correlating
to the force exerted on the sensing element.
15. The system of claim 14, wherein the occupancy sensor is placed
between the support structure and the static object.
16. The system of claim 14, wherein the module determines an
occupancy status of a user based on the sensed resistance.
17. The system of claim 14, wherein the module determines an
occupancy status of a user based on the force exerted on the
sensing element being above or below a load or unload
threshold.
18. The system of claim 14, wherein the module wirelessly transmits
a signal indicating an occupancy status to a computing device.
19. The system of claim 18, wherein the occupancy sensor and the
computing device are wirelessly coupled together as part of an
activity monitoring system.
20. The system of claim 14, wherein the occupancy sensor is battery
powered.
Description
CROSS REFERENCE
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/183,224, filed Jul. 14, 2011, which is
issuing as U.S. Pat. No. 8,783,114 on Jul. 22, 2014 and is related
to, and claims priority to, U.S. Provisional Application No.
61/364,255, filed on Jul. 14, 2010, entitled "BED OCCUPANCY
SENSOR," and having Attorney Docket No. 138.015999P, the content of
which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] In the field of remote health monitoring, systems have been
developed to monitoring the activity of a user in a dwelling. For
example, in various systems, an individual's activities can be
monitoring using a number of sensors.
[0003] Activity monitoring systems include motion sensors, for
example, that are connected to a base control system that monitors
areas within the dwelling for movement. When a lack of movement is
indicated, the system indicates the lack of movement to a remote
assistance center that can contact a party to aid the individual.
However, not all inactivity indicates that an individual is in need
of assistance. For example, an individual can be sitting in a chair
for a prolonged period, or lying in bed. These periods may be
sufficient to initiate an alert for third party response, but may
not actually be an emergency.
[0004] Many of the current sensors marketed for the detection of a
person occupancy status can be complex, expensive, and line
powered, and use a proprietary computer interface for calibration
or data collection. Other occupancy detection systems use switch
type sensors. The switch type sensors have not been found to be a
reliable detection of occupancy as it is difficult if not
impossible to calibrate the sensor to the application. In a bed
occupancy detection system, switch type sensors may work in a
typical box-spring bed, but may not switch and/or switch
intermittently when loaded in a luxury mattress installation where
the loading is better spread over the bed structure, thus limiting
the amount of force applied to the sensor. Switch type sensors may
not have a hysteresis band between the load and unload force and
have been found to switch on/off frequently in a situation where
the occupant moves frequently and/or where the application is near
the force level needed to activate the switch, thus causing
difficulty in analyzing and using the sensor data from the
occupancy detection switch in an activity monitoring system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates an occupancy sensor according to an
embodiment of the present disclosure.
[0006] FIG. 2 illustrates an occupancy sensing system according to
an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0007] Embodiments of the present disclosure relate to methods,
devices, and systems for determining occupancy of a user. One
method to determine occupancy of a user includes sensing a change
in resistance of a sensor element of an occupancy sensor,
correlating the change in resistance to a force transmitted to the
occupancy sensor, and determining an occupancy status of a user
based on the force transmitted.
[0008] The Figures herein follow a numbering convention in which
the first digit or digits correspond to the drawing Figure number
and the remaining digits identify an element or component in the
drawing. Similar elements or components between different Figures
may be identified by the use of similar digits.
[0009] For example, 112 may reference element "12" in FIG. 1, and a
similar element may be referenced as 212 in FIG. 2. As will be
appreciated, elements shown in the various embodiments herein can
be added, exchanged, and/or eliminated so as to provide any number
of additional embodiments of the system. In addition, the elements
shown in the various embodiments are not necessarily to scale.
[0010] FIG. 1 illustrates an occupancy sensor 100 according to an
embodiment of the present disclosure. Occupancy sensor 100 can use
a force exerted on the occupancy sensor by a user to determine the
occupancy status of the user. Occupancy sensor 100 can be used to
determine the occupancy status of the user in a variety of
settings, such as in a bed, in a chair, and/or on the floor of a
room, for example, among other settings. Occupancy sensor can be
used to determine the occupancy status of a user in relation to any
object that has a support structure for the occupancy sensor.
[0011] In one or more embodiments, the occupancy sensor 100 in FIG.
1 can include a sensor element 110. Sensor element 110 can be a
force sensitive resistor (FSR) element. An FSR element can be a
transducer having a resistance that varies based on the force
exerted on the FSR element, i.e., the resistance of the FSR element
varies as the force exerted on the FSR element varies. The
resistance of the FSR element can, in turn, be converted to a
voltage. The voltages sensed that are caused by forces exerted on
the FSR element can be calibrated and correlated to the forces
exerted on the FSR element, so that resistances sensed by circuitry
coupled to the FSR element can correlated to the forces exerted on
the FSR element.
[0012] In one or more embodiments, the sensor element 110 can be
coupled to a base 102. Base 102 can be a semi-rigid polymer base,
for example, among other materials. The width of base 102 can vary
so that the base is supported by a support structure on which it is
placed. A base that is supported by the support structure on which
it is placed can reduce variability in sensitivity of an
occupancies sensitivity based on location on the structure. The
semi-rigid polymer base can provide support for the sensor element
110 so that forces exerted on the sensor element 102 result in
changes in resistance in the sensor element 110.
[0013] In one or more embodiments, an activator bar 104 can be
placed over the sensor element 110 and be coupled to base 102. The
activator bar 104 can be placed over the sensor element 110 so that
a portion of the sensor element on the ends of the activator bar
104 is exposed. The exposed portion of the sensor element 110 can
be used to couple the sensor element 110 to a module via a cable
connector 112. A first end of cable connector 112 can be coupled to
a portion of the sensor element 110 and a second end of cable
connector can be coupled to a module. The cable connector 112 can
transfer signals between the sensor element and the module. The
module can receive and sense the variable resistances and voltages
associated with the forces exerted on the sensor element 110.
[0014] The activator bar 104 can be a semi-rigid polymer with a
resilient, low compression set foam rubber compound, for example,
among other materials. The activator bar 104 can transfer force
from the mattress and/or user to the sensor element 110. The
activator bar 104 can be formed of materials with variable
stiffness, so that the changes in resistance in a sensor element
110 caused by forces being transferred to the sensor element 110 by
the activator bar 104 can vary based on the stiffness of the
activator bar material. The width of the activator bar 104 can also
affect the change in resistance in a sensor element 110 caused by
forces transferred to the sensor element 110 by the activator bar
104. A wider activator bar can transfer more force to the sensor
element 110 causing a greater change in resistance in the sensor
element 110 than a narrower activator bar. The activator bar 104
can be surrounded by edge supports 106. The edge supports 106 can
be formed of the same and/or similar material as the activator bar
104 can counteract the fixed forced exerted on the bed occupancy
sensor by the weight of a static object, such as a mattress, for
example, so that the sensor element 110 does not change resistance
due to the weight of the static object.
[0015] In one or more embodiments, occupancy sensor 100 can include
fasteners 108-1, 108-2, 108-3, and 108-4. A number of fasteners,
such as fasteners 108-1, 108-2, 108-3, and 108-4 in FIG. 1, can be
used to fasten the occupancy sensor 100 to a structure. Fasteners
108-1, 108-2, 108-3, and 108-4 can be grommets, among other
fastening mechanisms, for example. The occupancy sensor 100 can be
covered in a cleanable and/or moisture resistant cover.
[0016] In one or more embodiments, an occupancy sensor can detect a
user's occupancy on an object for use with an activity monitoring
system that operates by detecting periods of inactivity of a user
that may indicate a need for assistance. The occupancy sensor can
use a battery powered circuit for transmission of signals that
indicate occupancy and/or out of bed conditions. The occupancy
sensor may also be used in situations where an exit event is cause
for assistance to prevent falls.
[0017] The occupancy sensor can be used in a passive monitoring
system to detect periods of inactivity that may indicate a
condition where assistance is needed. In activity monitoring
systems, a period of sleep can exceed the time without activity
alert that the activity monitoring system uses to gage assistance
needs, therefore an occupancy sensor can be used to activate a
sleep timer in the activity monitoring system to allow the user to
rest without generating the automated alerts.
[0018] In one or more embodiments, the calibration process for an
occupancy sensor can be initiated by inserting a cable connector
from the sensor element into a jack on a module. The jack contains
a switch to detect the insertion of a cable connector. The
circuitry of the module can conduct a calibration by sampling the
resistance reading from the sensor element and averaging over the
calibration period to determine tare, e.g., an unloaded mattress
condition. The tare result can then used to calculate a load
threshold and a corresponding unload threshold. The calculated
thresholds can be chosen based on a number of factors, such as a
logarithmic load/resistance characteristic of the sensor element,
among other factors. In various embodiments, a resistor divider can
be used in the module to scale a voltage reading that can be
converted to a scaled count reading. A parallel resistor can be
added to the sensor element to create an upper resistance reading,
hence an upper count value for an unloaded bed sensor. A fixed
resistor value in the divider network can be chosen to shift the
counts scale of the microprocessor such that the difference between
loaded and unloaded counts in the typical use range is sufficiently
large, while reducing the current draw of the sensing element.
[0019] In various embodiments, a load threshold must be satisfied
for a period of time for an occupancy sensor to detect a loaded
condition. The period of time is adjustable to allow the occupancy
sensor to be used to detect an exit event, e.g., fast detect,
and/or an activity of daily living, where the load/unload detection
time delay can be extended.
[0020] In various embodiments, the resistance level must exceed the
unload threshold also for a settable period of time for the bed
occupancy sensor to indicate an unload condition. Load and unload
thresholds can be calculated based on the unloaded calibration, but
can be adjusted remotely for a particular application if the
calculated load/unload thresholds do not sufficiently allow for
proper detection of occupancy status. A new calibration can be
performed anytime by simply unplugging and reinserting the plug.
New calibrations may be needed if an occupancy sensor is shifted
during cleaning or adjustment of sensor position.
[0021] In one or more embodiments, a combination of a cable
connector sense jack, and a baseline sensor element resistance can
provide the module with information to determine if the cable
connector is inserted and if the sensor element is reading a proper
resistance level. This information can be transmitted to an
activity monitoring system and can be further utilized with the
load/unload readings to troubleshoot an installation.
[0022] In one or more embodiments, the sensor element of the bed
occupancy sensor can use a low power circuit for monitoring bed
occupancy that can be battery powered. The nature of the resistive
circuit allows for rapid power up to sample the resistance value
and varying the duty cycle for powering the sensing circuit allows
the sensor to better optimize the battery life for the occupancy
sensor. The calibration of the sensor element can be conducted
without connecting to a computer device and/or other tool.
[0023] In one or more embodiments, two occupancy sensors can be
installed in an area that is too large for a single occupancy
sensor to properly detect occupancy, such as a queen or king size
bed, for example. Also, multiple sensors can be added to a single
area for increased occupancy detection assurance. A module can
include a number of independent inputs and circuitry to monitor a
number of occupancy sensors independently.
[0024] FIG. 2 illustrates an occupancy sensing system according to
an embodiment of the present disclosure. The occupancy system in
FIG. 2 can be a bed occupancy sensing system and include an
occupancy sensor 200 coupled to a bed structure 230. In various
embodiments, an occupancy sensing system can sense occupancy in a
chair, a room, and/or a portion of a residence, for example, among
other locations and/or objects.
[0025] In the occupancy sensing system of FIG. 2, bed structure 230
can be a bed frame, for example. In one or more embodiments, a bed
structure can be a floor, wherein a mattress is placed on the floor
of a room. A mattress 220 can be placed on the bed structure 230
and on occupancy sensor 200. The occupancy sensor 200 can be
coupled to a module 214 via a cable connector 212. The occupancy
sensor 200 and module 214 can be battery operated. The module 214
can sense signals transmitted from the occupancy sensor 200 via
cable connector 212. The module 214 can include circuitry that can
sense a resistance in the bed occupancy sensor 200 and convert the
resistance sensed to a voltage. The changes in the resistance in
the occupancy sensor caused by changes in force exerted on the
occupancy sensor can be sensed by the module 214 and converted to a
voltage that is calibrated and corresponds to the force exerted on
the occupancy sensor.
[0026] In one or more embodiments, the occupancy sensor 200 can be
part of an activity monitoring system that includes a number of
sensors that can communicate to each other and/or a computing
device. The module 214 can communicate with other sensors and/or
computing devices by transmitting signals wirelessly. The signals
communicated between the number of sensors and/or computing devices
can be analyzed and used to monitor the activities of a user in a
residence. In various embodiments, an activity monitoring system
can include a number wireless access points that can provide
wireless access to a wireless network, such as a Wireless Local
Area Network (WLAN), by transferring signals on one or more
channels between various components of the wireless network, such
as sensors, base stations, and/or computing devices, among other
components.
[0027] Embodiments of the present disclosure relate to methods,
devices, and systems for determining bed occupancy. One method to
determine occupancy of user includes sensing a change in resistance
of a sensor element of an occupancy sensor, correlating the change
in resistance to a force transmitted to the occupancy sensor, and
determining an occupancy status of a user based on the force
transmitted.
[0028] Although specific embodiments have been illustrated and
described herein, those of ordinary skill in the art will
appreciate that an arrangement calculated to achieve the same
techniques can be substituted for the specific embodiments shown.
As one of ordinary skill in the art will appreciate upon reading
this disclosure, various embodiments of the invention can be
performed in one or more devices, device types, and system
environments including networked environments.
[0029] Combination of the above embodiments, and other embodiments
not specifically described herein will be apparent to those of
skill in the art upon reviewing the above description. The scope of
the various embodiments of the disclosure includes other
applications in which the above structures and methods can be used.
Therefore, the scope of various embodiments of the disclosure
should be determined with reference to the appended claims, along
with the full range of equivalents to which such claims are
entitled.
[0030] In the foregoing Detailed Description, various features may
have been grouped together in a single embodiment for the purpose
of streamlining the disclosure. This method of disclosure is not to
be interpreted as reflecting an intention that the embodiments of
the invention require more features than are expressly recited in
each claim.
[0031] Rather, as the following claims reflect, inventive subject
matter lies in less than all features of a single disclosed
embodiment. Thus, the following claims are hereby incorporated into
the Detailed Description, with each claim standing on its own as a
separate embodiment.
* * * * *