U.S. patent application number 11/876969 was filed with the patent office on 2008-02-14 for systems and methods for adaptation to wireless remote control of irrigation valves from existing hardwired control devices.
This patent application is currently assigned to NPD CORP.. Invention is credited to Glen Gary Graham.
Application Number | 20080039978 11/876969 |
Document ID | / |
Family ID | 35941668 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080039978 |
Kind Code |
A1 |
Graham; Glen Gary |
February 14, 2008 |
SYSTEMS AND METHODS FOR ADAPTATION TO WIRELESS REMOTE CONTROL OF
IRRIGATION VALVES FROM EXISTING HARDWIRED CONTROL DEVICES
Abstract
A low cost system and method for retrofitting an existing
control device to communicate wirelessly with one or more
water-flow devices is provided. For example, an existing wired
irrigation system may be adapted to allow wireless communication
between a commercially available irrigation controller and
commercially available water-flow devices, such as sprinkler
valves. A wireless irrigation adapter receives control signals from
an existing irrigation controller and transmits a wireless
representation of the control signals. Water-flow devices may be
coupled to one or more wireless receivers that receive the wireless
representation of the control signals and operate the water-flow
device(s) accordingly. The wireless irrigation receiver(s)
listen(s) for the wireless control signals occasionally, thus
reducing power consumption by the wireless receiver(s). This system
and method may also wirelessly adapt control devices to irrigation
that may never have been intended for that purpose when they were
fabricated.
Inventors: |
Graham; Glen Gary;
(Riverside, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
NPD CORP.
Riverside
CA
|
Family ID: |
35941668 |
Appl. No.: |
11/876969 |
Filed: |
October 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11209590 |
Aug 22, 2005 |
7286904 |
|
|
11876969 |
Oct 23, 2007 |
|
|
|
60603432 |
Aug 21, 2004 |
|
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Current U.S.
Class: |
700/284 |
Current CPC
Class: |
Y10T 137/189 20150401;
G05B 2219/2625 20130101; G05B 2219/25187 20130101; A01G 25/16
20130101; G05B 2219/25289 20130101 |
Class at
Publication: |
700/284 |
International
Class: |
G06F 19/00 20060101
G06F019/00 |
Claims
1. method of retrofitting a hard-wired irrigation system for
wireless communication, wherein the hard-wired irrigation system
comprises an irrigation controller that is adapted to be
electrically coupled to at least one irrigation solenoid valve by
one or more physical wires, the irrigation controller being adapted
to output control signals to the irrigation solenoid valve via the
one or more physical wires, the method comprising: wiring a
wireless adapter to at least one output of the irrigation
controller so that the wireless adapter receives the control
signals; wiring a wireless receiver to the irrigation solenoid
valve; and inducing the wireless adapter to transmit a transformed
version of the received control signals, wherein in response to
receiving the transformed version of the control signals, the
wireless receiver activates the irrigation solenoid.
2. The method of claim 1, further comprising: inducing the wireless
adapter to transmit a second transformed version of the received
control signals, wherein in response to receiving the second
transformed version of the control signals, the wireless receiver
deactivates the irrigation solenoid.
3. The method of claim 1, wherein the irrigation controller
comprises at least one of: a sprinkler time, a personal computer, a
Programmable Logic Controller (PLC), a manual switch, an Air
Conditioning Thermostat, a SPA or Pool timer, and a sequencer.
4. A method of controlling an irrigation system, the irrigation
system comprising an irrigation solenoid valve electrically coupled
to a wireless receiver and an irrigation controller electrically
coupled to a wireless adapter, the method comprising: transmitting
an activation control signal from the wireless adapter, the
activation control signal being representative of an activation
signal received from the irrigation controller indicating that the
irrigation solenoid valve should be activated in order to allow
water to flow through the irrigation solenoid valve to one or more
water distribution devices that are in fluidic communication with
the irrigation solenoid valve; receiving the activation control
signal at the wireless receiver, wherein the wireless receiver
alternates between a listen period and a sleep period, wherein
during the sleep period the wireless receiver draws less power than
in the listen period and the activation control signal is only
detected by the wireless receiver during the listen period; in
response to receiving the activation control signal, activating the
irrigation solenoid valve; and de-activating the irrigation
solenoid valve if the activation control signal is not again
received during a predetermined quantity of one or more of the
listen and the sleep periods, thereby reducing a likelihood of the
irrigation solenoid valve over-watering.
5. The method of claim 4, further comprising de-activating the
irrigation solenoid valve in response to receiving a deactivation
control signal from the wireless adapter so as to inhibit flow of
water through the irrigation solenoid valve to the one or more
water distribution devices.
6. The method of claim 4, wherein the activation control signal is
periodically transmitted at a rate that is equal to or less than
the predetermined quantity of one or more of the listen and the
sleep periods.
7. The method of claim 4, wherein the sleep period is more than two
times the duration of the listen period.
8. The method of claim 4, wherein the activation control signal is
transmitted no more than about 25% of the time during a period in
which the irrigation solenoid is to be activated.
9. The method of claim 4, wherein the activation control signal is
transmitted for less than about 15 seconds.
10. The method of claim 4, wherein the predetermined quantity is
selected from the group comprising 2, 3, 4, 5, 6, 7, 8, 9, 10, 15,
20, 30, 50, 100, and 200.
11. A wireless irrigation adapter comprising: one or more input
connections for hard-wiring to respective output connections of an
irrigation controller, at least some of the output connections of
the irrigation controller each being configured to output
indications of when one or more irrigation valves associated with
respective output connections are to be active; a wireless
transmitter for transmitting an activation signal indicating one or
more of the irrigation valves; and a first wireless receiver
coupled to a first irrigation valve and coupled to receive an AC
power signal from an AC power source, wherein, in response to
receiving the activation signal indicating the first irrigation
valve, the first wireless receiver initiates activation of the
first irrigation valve so as to allow water to flow to one or more
water distribution devices coupled to the first irrigation
valve.
12. The wireless irrigation adapter of claim 11, wherein the first
wireless receiver activates the first irrigation valve by coupling
the AC power signal from the AC power source to the first
irrigation valve during all of an activation period.
13. The wireless irrigation adapter of claim 11, and the wireless
irrigation adapter further comprises: a second wireless receiver
coupled to a second irrigation valve that is battery powered,
wherein, in response to receiving the activation signal indicating
the second irrigation valve, the second wireless receiver initiates
activation of the second irrigation valve so as to allow water to
flow to one or more water distribution devices coupled to the
second irrigation valve.
14. The wireless irrigation adapter of claim 13, wherein the second
wireless receiver activates the second irrigation valve by coupling
a DC power signal from a battery to a DC solenoid of the second
irrigation valve for a brief period at the beginning of an
activation period.
15. The wireless irrigation adapter of claim 14, wherein the brief
period is less than about 500 milliseconds.
16. The wireless irrigation adapter of claim 13, wherein the second
wireless receiver alternates between a listen period and a sleep
period, wherein during the sleep period the second wireless
receiver draws less power than in the listen period and the
activation signal is only detected by the second wireless receiver
during the listen period.
17. The wireless irrigation adapter of claim 16, wherein the second
wireless receiver is configured to initiate deactivation of the
second irrigation valve in response to not receiving the activation
signal indicating the second watering zone in a predetermined
number of one or more of the sleep and the listen periods.
18. A wireless adapter system for use with an irrigation controller
that is configured for hard-wiring to one or more irrigation valves
associated with respective of one or more watering zones, wherein
each of the irrigation valves is coupled to one or more water
distribution devices and the irrigation valves are configured to
control passage of water to respectively coupled water distribution
devices, the irrigation controller further comprising a separate
electrical connection for hard-wiring to each of the one or more
irrigation valves, the wireless adapter system comprising: a
wireless transmitter comprising a plurality of input connections
configured for coupling to the electrical connections of the
irrigation controller so that the wireless transmitter receives
control signals from the irrigation controller and the wireless
transmitter periodically transmits a wireless signal indicative of
which watering zones should be active in accordance with the
control signals from the irrigation controller on the input
connections; and one or more wireless receivers associated with
respective of the irrigation valves, wherein the wireless
receivers, in response to receiving the wireless signal,
selectively activate their corresponding irrigation valves, wherein
the wireless receivers are further adapted to de-activate their
respective irrigation valves if the wireless signal is not detected
during a pre-determined time interval to thereby reduce the
likelihood of the irrigation valve over-watering due to not
detecting the wireless signal during the pre-determined time
interval.
19. The wireless adapter system of claim 18, wherein the wireless
transmitter is configured to transmit a wireless signal indicative
of which watering zones should not be active, as indicated by the
control signals from the irrigation controller on the input
connections, and the wireless receivers, in response to receiving
the wireless signal, selectively de-activate the irrigation valves
of their respective watering zones as indicated by the wireless
signal.
20. The system of claim 18, wherein at least one of the wireless
receivers is battery operated and alternates between a sleep state
and an awake state.
21. The system of claim 18, wherein the wireless transmitter
transmits the first wireless signal not more than once every two
awake states.
22. The system of claim 20, wherein the pre-determined time
interval comprises a total duration of a predetermined quantity of
one or more of the sleep states and awake states.
23. The system of claim 18, wherein the pre-determined time
interval comprises a quantity of one or more seconds, minutes, or
hours.
24. The system of claim 18, wherein one or more of the sprinkler
valves comprises a DC-latching solenoid valve.
25. The system of claim 22, wherein the wireless signal comprises
encoded data indicating one or more of the wireless receivers for
which the wireless signal is intended.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/209,590, filed on Aug. 22, 2005, which
claims priority under 35 U.S.C. .sctn. 119(e) to U.S. Provisional
Application Ser. No. 60/603,432 filed on Aug. 21, 2004, each of
which is hereby expressly incorporated by reference in their
entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to systems and methods for
controlling automated irrigation systems and, more particularly, to
systems and methods for retrofitting existing irrigation systems
for wireless communication and providing low power wireless
communication devices.
[0004] 2. Description of the Related Art
[0005] A typical irrigation system comprises an irrigation
controller, which include some timing and scheduling functionality,
which is hardwired to one or more irrigation valves that are
configured to control flow of fluid through the valves based on
signals received from the irrigation controller. In these
irrigation systems, in order to be able to control a newly
installed irrigation valve, wires must physically be run from the
irrigation controller to the new irrigation valve. As those of
skill in the art will recognize, the connecting wires are typically
buried in an underground trench and may be encased in additional
protective material, such as PVC piping, for example. Thus,
depending on the land features between the irrigation controller
and the irrigation valves, placement of the wires may require
considerable labor and expense.
[0006] One alternative to the use of an irrigation system having
physical wires between the irrigation controller and the valves is
the replacement of the wired irrigation system with a smart
irrigation system, including a smart irrigation controller having
built-in wireless communication capabilities. However, after
replacing a wired irrigation controller with a smart irrigation
controller, the irrigation valves must also be replaced with smart
irrigation valves having built-in wireless communication
capabilities in order to communicate with the replaced smart
irrigation controller. In some cases, each of the smart irrigation
valves comprise a timing module configured to determine and monitor
the irrigation duration of the smart irrigation valve. Thus, a
schedule may be wirelessly sent to the smart irrigation valve and
the timing module may activate the smart irrigation valve according
to the received schedule. As those of skill in the art will
recognize, however, implementation of a timing module in smart
irrigation valves requires some computing capabilities in the smart
irrigation valve and, thus, the irrigation valve may require more
power than a typical wired irrigation valve. In addition, in order
to implement one of these smart irrigation systems into an existing
system, the irrigation controller must be replaced with a smart
irrigation controller having built-in wireless capabilities and, in
order to communicate with the smart irrigation controller, the
irrigation valves need to be replaced with smart irrigation valves
having built-in wireless capabilities. Accordingly, currently
available systems for implementing a wireless irrigation system
require complete replacement of existing components and, thus,
require significant expense. Systems and methods for allowing
existing irrigation systems to be upgraded to communicate
wirelessly are desired. More particularly, systems and methods for
retrofitting existing irrigation controllers and irrigation valves
so that wireless communications may be transmitted between the
devices are desired.
SUMMARY OF THE INVENTION
[0007] The system, method, and devices of the invention each have
several aspects, no single one of which is solely responsible for
its desirable attributes. Without limiting the scope of this
invention, its more prominent features will now be discussed
briefly. After considering this discussion, and particularly after
reading the section entitled "Detailed Description of Certain
Embodiments" one will understand how the features of this invention
provide advantages over other irrigation control systems.
[0008] In one embodiment, a low cost system and method for
retrofitting an existing irrigation system to communication
wirelessly is provided. For example, an existing wired irrigation
system may be adapted to allow wireless communication between a
commercially available irrigation controller and commercially
available water-flow devices (such as irrigation valves, including
existing or newly acquired irrigation valves).
[0009] In one embodiment, a wireless adaptor system for use with an
existing hard-wired irrigation system includes sprinkler valves
with associated wires and a controller that outputs at least a
first set of control signals on the wires so as to activate
sprinkler valves connected to the wires. The adaptor system
comprises a wireless transmitter that is coupled to one or more
control wires of the hard-wired irrigation system such that the
wireless transmitter receives the first set of control signals from
the sprinkler controller and the wireless transmitter, in response
to receiving the first set of control signals periodically sends a
first wireless signal so as to enable a sprinkler valve, and a
wireless receiver coupled to the sprinkler valve wherein the
wireless receiver, in response to receiving the first wireless
signal, activates the sprinkler valve and wherein the wireless
receiver is adapted to de-activate the sprinkler valve if the first
periodic wireless signal is not detected during a pre-determined
time interval to thereby reduce the likelihood of the sprinkler
valve over-watering.
[0010] In another embodiment, a method of controlling an irrigation
system comprising a sprinkler valve electrically coupled to a
wireless receiver and an irrigation controller electrically coupled
to a wireless adapter comprises periodically transmitting a control
signal from the wireless adapter, the control signal being
representative of a signal received from the irrigation controller
indicating that the sprinkler valve should be activated, receiving
the control signal at the wireless transmitter, in response to
receiving the control signal, activating the sprinkler valve, and
de-activating the sprinkler valve if the first signal is not
detected during a predetermined time interval to thereby reduce the
likelihood of the sprinkler valve over-watering.
[0011] In another embodiment, a wireless receiver coupled to a
sprinkler valve comprises means for activating the sprinkler valve
in response to receiving a periodic wireless control signal
indicating a desired state of the sprinkler valve, and means for
deactivating the sprinkler valve if the periodic wireless control
signal is not again detected during a pre-determined time interval
after being initially received.
[0012] In another embodiment, a method of retrofitting a hard-wired
irrigation system for wireless communication, wherein the
hard-wired irrigation system comprises an irrigation controller
that is adapted to be electrically coupled to a sprinkler valve by
a physical wire, the irrigation controller being adapted to output
control signals to the sprinkler valve via the physical wire,
coupling a wireless adapter to outputs of the irrigation controller
so that the wireless adapter receives the control signals, coupling
a wireless receiver to the control wires of the sprinkler valve,
inducing the wireless adapter to transmit a transformed version of
the received control signals, wherein in response to receiving the
transformed version of the control signal, the wireless receiver
activates the sprinkler for a predetermined time period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram of an irrigation system
[0014] FIG. 2 is a block diagram illustrating components of the
exemplary wireless irrigation adapter of FIG. 1.
[0015] FIG. 3 is a block diagram illustrating components of the
exemplary wireless receiver of FIG. 1.
[0016] FIG. 4 is a flowchart illustrating an exemplary method of
operation for the wireless receiver of FIG. 1.
[0017] FIG. 5 is a timing diagram illustrating an exemplary output
signal from the wireless irrigation adapter 210 and of the signal
received by an exemplary irrigation valve 110.
[0018] FIG. 6 is a block diagram illustrating exemplary components
of the decode module, latch module, and output module of an
exemplary wireless receiver.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Embodiments of the invention will now be described with
reference to the accompanying Figures, wherein like numerals refer
to like elements throughout. The terminology used in the
description presented herein is not intended to be interpreted in
any limited or restrictive manner, simply because it is being
utilized in conjunction with a detailed description of certain
specific embodiments of the invention. Furthermore, embodiments of
the invention may include several novel features, no single one of
which is solely responsible for its desirable attributes or which
is essential to practicing the inventions herein described.
[0020] The term "module," as used herein, means, but is not limited
to, a software or hardware component, such as a field programmable
gate array (FPGA) or an application specific integrated circuit
(ASIC), which performs certain tasks. A module may advantageously
be configured to reside on an addressable storage medium and
configured to execute on one or more processors. Thus, a module may
include, by way of example, components, such as software
components, object-oriented software components, class components
and task components, processes, functions, attributes, procedures,
subroutines, segments of program code, drivers, firmware,
microcode, circuitry, data, databases, data structures, tables,
arrays, and variables. The functionality provided for in the
components and modules may be combined into fewer components and
modules or further separated into additional components and
modules.
[0021] The terms "irrigation valve" and "valve" are used herein
interchangeably and should be interpreted to include any fluid
controlling device configured to control passage of a fluid in
response to a received electrical signal. In certain embodiments,
each of the irrigation valves is coupled to one or more spray
heads, rotors, drip systems, flood systems, ditches, gate valves,
or other fluid delivery devices that are configured to deliver
water to one or more watering zones associated with the respective
valve. In one embodiment, an irrigation valve includes one or more
electromagnetic coils, through which current passes, by various
means, to enable or disable the flow of fluid through the
valve.
[0022] FIG. 1 is a block diagram of an exemplary wireless
irrigation system 200, including a wireless irrigation adapter 210
configured to interface a commercially available irrigation
controller, such as the irrigation controller 102. As illustrated
in FIG. 1, the exemplary wireless irrigation system 200 comprises
the irrigation controller 102 and irrigation valves 110A, 110B,
110C, wherein communication between the irrigation controller 102
and the irrigation valves 110A, 110B, 110C is wireless, removing
the need for physical wires between the devices. In the embodiment
of FIG. 1, the irrigation controller 102 is also coupled to
irrigation valves 110D, 110E in a conventional manner, i.e., with
physical wires 205 extending from the irrigation controller 102 to
the irrigation valves.
[0023] In one embodiment, the irrigation valves 110A, 110B, 110C
are each electrically coupled to a wireless receiver 220, which are
each configured to receive wireless communications from the
wireless irrigation adapter 210. In other embodiments, a wireless
receiver is coupled to control multiple irrigation valves. As
explained in further detail below, the physical wires 205 from the
irrigation controller 102 are coupled to the wireless irrigation
adapter 210 that communicates wirelessly with the wireless
receivers 220, rather than requiring the physical wires 205 to
extend from the irrigation controller 102 to the irrigation valves
110.
[0024] In operation, the wireless irrigation adapter 210 receives
control signals on wires 205 from the irrigation controller 102
that are intended for delivery to the irrigation valves 110 via
wired connections. The wireless irrigation adapter 210 converts
these control signals into signals that are suitable for wireless
transmission. For example, the control signals may be converted to
RF signals that may be transmitted from an antenna in, or
electrically coupled to, the wireless irrigation adapter 210. In
other embodiments, optical signals representing the control signals
received on wires 205 are transmitted by the wireless irrigation
adapter 210.
[0025] In one embodiment, the irrigation controller 102 comprises a
step-down transformer that supplies an activation signal to the
irrigation valves 110. For example, many irrigation controllers
include 24 VAC step-down transformers. In one embodiment, one wire
on the output-winding side of the step-down transformer may be used
as a common wire (also referred to as a cold, return, or neutral
wire). In this embodiment, a second wire on the output-winding side
of the step-down transformer is the hot wire that supplies an
electrical current. Thus, a load, such as a coil of one of the
irrigation valves 110, that is placed between the common wire and
the hot wire will be energized.
[0026] In one embodiment, each of the irrigation valves 110
comprises a solenoid that is configured to generate a force
sufficient to open and close the valve 110 in response to the
application of a 24 VAC to the solenoid. For example, when a
voltage, such as a 24 VAC signal, is applied across a solenoid, the
solenoid generates a magnetic field that causes a valve mechanism
to move within the valve 110 and thereby allows water to flow
through the valve 110. When the voltage is removed from the
solenoid, the magnetic field may also be removed and the valve
mechanism closes so that the water no longer flows through the
valve 110. Those of skill in the art will recognize that other
methods of wiring an irrigation controller 102 to multiple
irrigation valves 110 and controlling operation of the valves 110
are well known in the art. The systems and methods described herein
are not particular to any one configuration of irrigation system
but, to the contrary, may be used with any known irrigation
system.
[0027] The wireless irrigation adapter 210 transmits one or more
wireless signals, which are referred to herein collectively as a
wireless control signal 230 or a control signal 230, so that the
wireless control signal 230 is received by the wireless receivers
220. In one embodiment, the wireless control signal 230 comprises a
single, serial data transmission containing data intended for each
of the wireless receivers 220. In another embodiment, the wireless
control signal 230 comprises multiple data signals, such as at
different frequencies, phases, or power levels, that are each
intended for reception by one or more of the wireless receivers
220. In other embodiments, the control signal 230 comprises various
combinations of wireless signals that are known in the art for
point-to-multi-point communication. As described in further detail
below with respect to FIG. 5, the wireless irrigation adapter 210
may be configured to periodically transmit the control signals 230
and the wireless receivers 220 may be configured to periodically
receive the control signals 230. Accordingly, a total power used by
the wireless irrigation system 200 may be significantly lower than
a system that uses always-on wireless transmitters and
receivers.
[0028] The wireless receivers 220 are configured to receive the
transmitted wireless control signal 230 and transform the received
control signal 230 in order to determine if respective irrigation
valves 110 should be activated. The wireless receivers 220 are
further configured to transform the received control signal 230 to
an output signal that appropriately activates (opens the valve and
allows fluid to pass through the valve) or deactivates (closes the
valve, stopping fluid from passing through the valve) one or more
irrigation valves according to the data contained in the control
signal 230.
[0029] In one embodiment, the irrigation valves 110 that are
controlled by the wireless receivers 220 each comprise one or more
bistable, DC-latching solenoid valves. These DC-latching solenoid
valves may advantageously be activated and deactivated by a forward
or reverse bias DC pulse, respectively. In this embodiment, the
wireless receivers 220 provide the appropriate DC current and
polarity to the respective irrigation valve 110 in order to
activate and deactivate the valve 110.
[0030] Advantageously, the addition of the wireless irrigation
adapter 210 and the wireless receivers 220 do not require the
replacement of the irrigation controller 102 or the irrigation
valves 110. In one embodiment, however, AC solenoid valves are
replaced with DC-latching solenoids in order to reduce power
consumption by these irrigation valves. In an embodiment having
valves 110 with DC-latching solenoids, the wireless receivers 220
may operate the valves 110 for extended periods. In one embodiment,
DC-Latching solenoids only need power during switching on
transitions between the activated and the deactivated states. Thus,
the use of DC-latching solenoids may advantageously allow the
valves 110 to be operated for longer time periods using less power,
such as may be provided by a battery powered wireless receiver, In
addition, the scheduling information in the irrigation controller
102 does not need to be reprogrammed in order to operate the
irrigation valves 110 via the wireless control signal 230. Instead,
the irrigation controller 102 continues to control the time periods
during which the irrigation valves 110 are activated and
deactivated. The wireless irrigation adapter and wireless receivers
220 provide a wireless link between the irrigation controller 102
and the irrigation valves 110.
[0031] Although discussion of the wireless irrigation system 200
herein describes half-duplex communication transmitted from the
wireless irrigation adapter 210 to the wireless receiver 220, other
embodiments may be full-duplex, wherein the wireless receiver 220
transmits feedback information to the wireless irrigation adapter.
In addition, in some embodiment, wireless repeaters may be located
between the wireless irrigation adapter 210 and the wireless
receivers 220 in order to extend a communication range of the
wireless irrigation system 200. Wireless repeaters are well known
in the art. Any wireless repeater configured to receive and
retransmit the control signal 230 may be used as a repeater in the
embodiments described herein. Similarly, wireless repeaters may be
utilized that are either half-duplex or full-duplex.
[0032] The irrigation controller 120 described herein refers not
only to pre-existing irrigation controllers, but also includes
those electronic devices, such as computing devices, that may be
programmed to maintain irrigation schedules and output appropriate
control signals. Because the inputs of the wireless irrigation
adapter 120 may be set to accept any DC or AC voltage input level
from 3 Volts to 240 Volts, for example, other devices, which may
never have been intended for irrigation use, may be programmed to
interface with the wireless irrigation adapter 210 and operate one
or more irrigation valves 110. For example, industrial controllers,
designed for factory use, such as Personal Computers, Programmable
Logic Controllers (PLCs), motor sequencers, lighting timers, Air
Conditioning Thermostats, as well as other controllers, sequencers
and switching devices, may be adapted to perform the irrigation
scheduling tasks typically performed by the irrigation controller
102. Thus, these devices may be coupled to provide control signals
to the wireless irrigation adapter 210 that indicate when one or
more valves should be activated. Accordingly, any reference to a
pre-existing irrigation controller 102 should be interpreted to
include not only specially designed irrigation controllers, but
also any other device that may be utilized to control irrigation
schedules.
[0033] In embodiments where the wireless irrigation adapter 210 is
coupled to a controller that doesn't output 24 VAC control signals,
a separate 24 VAC power source may be coupled to the wireless
irrigation adapter 210. In one embodiment, a 24 VAC signal is
supplied by a step-down transformer coupled to a 110 VAC power
outlet, for example. In other embodiments, the wireless irrigation
adapter 210 may be configured to operate using various other power
supply voltages, either DC or AC.
[0034] FIG. 2 is a block diagram illustrating components of the
exemplary wireless irrigation adapter 210 of FIG. 1. In the example
of FIG. 2, the irrigation controller 102 comprises a commercially
available multi-zone controller. The control signals are
transmitted to the irrigation adapter 210 via wires 205, as noted
above with regard to FIG. 1. The exemplary wireless irrigation
adapter 210 comprises a signal detector 310 that detects the
control signal on respective of the control lines. As noted above
with respect to FIG. 1, currently available irrigation controllers
102 typically output a 24 VAC signal in order to activate the
irrigation valves 110. In this embodiment, the signal detector 310
is configured to detect the presence of a 24 VAC signal on each its
input lines 311A, 311B, 311N. Accordingly, the signal detector 310
determines which of the wires 205 currently carry a 24 VAC signal
and, accordingly, determine if any of the valves should be
activated. In other embodiments, irrigation controllers provide
different output voltages. The signal detector 310 may be
configured to detect the presence of any electrical signal on the
input lines 311A, 311B, 311C, such as Normally-Open or
Normally-Closed switch-contacts, wired in series with any
detectable voltage source, that may be output by
non-irrigation-specific devices, e.g., PLCs, SPA-timers and
air-conditioning thermostats, etc.
[0035] The exemplary wireless irrigation adapter 210 also comprises
a power supply 320 that provides power to the electrical components
of the wireless irrigation adapter 210. In one embodiment, the
power supply 320 is electrically coupled to the irrigation
controller 102, and is provided with an output voltage from the
irrigation controller 102. For example, in one embodiment the
irrigation controller 102 provides the power supply with a 24 VAC
signal. In other embodiments, the irrigation controller 102 may
provide other voltage levels to the power supply 320. In one
embodiment, the power supply 320 may be directly connected to a
power outlet, such as a 110 VAC outlet. In other embodiments, the
power supply 320 is coupled to one or more alternative power
sources, such as a solar-cell. In one embodiment, the power supply
320 transforms and imports an input signal, such as a 24 VAC
signal, to an output DC signal that may be usable by the electronic
components within the wireless irrigation adapter 210, such as a 3V
or 5V DC signal.
[0036] In one embodiment, the wireless irrigation adapter 210
continuously transmits the wireless control signal 230. In other
embodiments, the wireless irrigation adapter 210 may be configured
to only occasionally, intermittently or periodically transmit the
wireless control signal 230, thereby reducing a power consumption
of the wireless irrigation adapter 210 and reducing the congestion
of transmitted radio frequency signals. An intermittently
transmitted control signal 230 may be advantageous in embodiments
where batteries supply power to the wireless irrigation adapter 210
or when reduction of RF signal congestion is necessary or
important. The exemplary wireless irrigation adapter 210 is
described including circuitry for periodically transmitting the
control signal 230. However, those of skill in the art will
recognize that the irrigation adapter 210 may be modified to
constantly transmit the wireless control signal 230.
[0037] In the embodiment of FIG. 2, a clock 330 is used to
determine when the control signal 230 should be transmitted. In one
embodiment, the clock 330 is an asymmetric clock that generates
clock signals that define transmit and sleep phases, where the
transmit phase has a transmit period and the sleep phase has a
sleep period. In one embodiment, each of the clock 330 cycles
includes both a transmit period and a sleep period, where the clock
signal indicates a transmit phase when high and a sleep phase when
low, for example. In another embodiment, separate clock cycles from
the clock 330 correspond with each of the transmit and sleep
phases. In other embodiments, the clock 330 may operate in any
suitable manner that allows distinction between the transmit phase
and the sleep phase.
[0038] In one embodiment, during the transmit phase the electronic
circuitry of the wireless irrigation adapter 210 draws power from
the power supply 320 and transmits the control signal 230, while in
the sleep phase at least some of the components of the wireless
irrigation adapter 210 are disabled are placed in low power modes.
For example, during the sleep phase, the latch module 340 and
transmission module (described in further detail below) may be
disabled or placed in low power modes. In one embodiment, the
transmit period is shorter than the sleep period. For example, the
sleep period may be a factor of 2, 3, 4, 5, 10, 20, or 50 times,
for example, longer than the transmit period. In one embodiment,
the transmit phase has a 25% duty-cycle, wherein some of the
circuitry of the wireless irrigation adapter 210 is disabled or
placed in low power modes.
[0039] The exemplary wireless irrigation adapter 210 comprises a
latch module 340 configured to hold the outputs from the signal
detector 310 during the transmit phase. In the embodiment of FIG.
2, the latch module 340 receives the output signals from the signal
detector 310 and the clock output from the clock 330. In one
embodiment the latch module 340 comprises a digital latch. In other
embodiments, the latch module 340 comprises any suitable device
that is capable of holding at least one digital signal and
providing the at least one digital signal on an output.
[0040] A transmission module 350 is configured to receive the
latched data signal, or signals, from the latch module 340 and
transmit the signal during the transmit phase. In one embodiment,
the transmission module 350 receives the output from the latch
module 340 only during the transmit phase, as indicated by the
clock signal generated by the clock 330. In one embodiment, the
transmission module transmits a UHF RF signal that is recognizable
by the wireless receivers 220 (FIG. 1). However, the transmission
module 350 may be configured to transmit any other protocol of
wireless signal that is suitable for transmission and reception in
the environment of an irrigation system. In one embodiment, the
transmission module 350 combines the latched signals received from
the latch module 340 into a serial digital data signal. In other
embodiments, the transmission module 350 transmits a wireless
control signal 230 comprising multiple RF signals having different
frequencies, phases, and/or power levels, for example. In one
embodiment, the transmission module is coupled to an antenna 360
that transmits the control signals 230.
[0041] The specific combination of components illustrated in
wireless irrigation adapter 210 of FIG. 2 are exemplary. Those of
skill in the art will recognize that various configurations and
arrangements of components may be used in performing the same
functions as performed by the exemplary wireless irrigation adapter
210. For example, fewer or more components, in various other
configurations, may be used in the wireless irrigation adapter
210.
[0042] FIG. 3 is a block diagram illustrating components of the
exemplary wireless receiver 220. As indicated above with respect to
FIG. 1, the wireless receiver 220 may be coupled to the irrigation
valve 110 in order to control operation of the irrigation valve 110
in accordance with a watering schedule stored at the irrigation
controller 102. In the embodiment of FIG. 3, the wireless receiver
220 comprises an antenna 410, a decode module 420, a power supply
430, a latch module 450, a clock 460, and an output module 470.
Each of these components will be described in further detail
below.
[0043] The antenna 410 is advantageously tuned to receive the
wireless control signal 230 that is radiated from the antenna 360
of the wireless irrigation adapter 210 (FIG. 2). The received
control signal 230 is then transmitted to a decode module 420 that
converts the signal to a usable digital output. Various methods of
transmitting and receiving digital signals are known in the art.
Any of these methods suitable for transmission of a data signal are
usable with the systems and methods described herein.
[0044] A power supply 430 comprises one or more voltage sources
that are electrically coupled to the components in the wireless
receiver 220 and provide power for operation of those components.
Because the wireless receivers 220 are co-located with the
irrigation valves 110, the power supply 430 typically comprises one
or more batteries. For example, in one embodiment the power supply
430 comprises a 9 V battery. In another embodiment, the power
supply 430 comprises two 9 V batteries. In other embodiments, the
power supply 430 may be coupled to a grid power supply, such as
through a standard 110 VAC electrical outlet, or the power supply
430 may be connected to one or more solar power sources, for
example. In one embodiment, the power supply comprises a 5 V
regulator circuit configured to convert a voltage received from a 9
V battery, for example, to a 5 V signal that is usable by the
electric components of the wireless irrigation adapter 210. The
regulator circuit may be also reduce noise that could adversely
affect proper operation of the circuitry within the wireless
irrigation adapter 210. In other embodiments, a voltage regulator
may convert an input voltage to a 3 V signal, or any other voltage
level that is usable by the electric components in the wireless
irrigation adapter 210.
[0045] In the exemplary embodiment of FIG. 3, a decode module 420
outputs a decoded control signal 421 to the latch module 450 that
is configured to store the decoded control signal 230 for a
predetermined period of time. A clock 460 is configured to provide
a clock signal to the decode module 420 and the latch module 450.
In one embodiment, the wireless receiver 220 has two modes of
operation, a listen mode and a sleep mode. During the listen mode,
the components of the wireless receiver 220 are actively listening
for wireless control signals 230. During the sleep mode, at least
some of the components of the wireless receiver 220 are disabled or
in low-power states. For example, during the sleep mode, the decode
module 420 may be disabled or placed in a low-power state. Thus,
the power consumption of the wireless receiver 220 may be reduced
when compared to a wireless receiver 220 that is always on.
[0046] In one embodiment, the clock 460 generates an asynchronous
clock signal that indicates when the wireless receiver 220 is in
the listen and sleep modes. In one embodiment, the clock 460
generates alternating pulses that correspond to the sleep and
listen modes, respectively, where a duration of the sleep pulse is
different than a duration of the listen pulse. For example, the
wireless receiver 220 may be in the sleep mode for a time period
that is much larger than the time period the wireless receiver 220
is in the listen mode. In another embodiment, a single clock cycle
comprising a combination of a low output followed by a high output,
represents both the sleep and listen modes. For example, when the
clock signal is low, the wireless receiver 220 may be in a sleep
mode and when the clock signal is high, the wireless receiver 220
may be in a listen mode. Other clock configurations that provide an
indication of alternating listen and sleep modes having different
durations are also possible.
[0047] In one embodiment, the latch module 450 advantageously holds
the decoded control signal 421 received during the listen mode for
a predetermined failsafe period, which may be longer than multiple
listen and sleep modes. In this embodiment, the state of the latch
will remain unchanged during the failsafe period so long as no new
decoded control signal 421 is received at the latch. When another
decoded control signal 421 is provided to the latch module 450, the
content of the latch is updated and the failsafe period is reset.
Thus, in order to maintain an activated state of a valve 110, a
control signal indicating that the valve 110 should remain
activated must be received by the wireless receiver 220 before the
end of the failsafe period. In one embodiment, the default position
of the valves 110 is deactivated. In this embodiment, if an
activation control signal has not been received by the wireless
receiver 220 during the failsafe period, the valve returns to the
default, deactivated position. In other embodiments, the default
position may be activate so that in order to maintain the valve in
the deactivated position, deactivate control signals must not be
separated by more than the failsafe period.
[0048] An output module 470 is configured to receive the decoded
control signal stored in the latch module 450 and generate an
appropriate signal to control the irrigation valve 110. For
example, if the latch module 450 output indicates that an
activation signal has been received from the wireless irrigation
adapter 210, the output module 470 generates and outputs an
appropriate activation signal to the irrigation valve 110, causing
the irrigation valve 110 to open. As the wireless receiver 220
enters the sleep mode, the decode module 420 may be disabled, while
the latch module 450 and output module 470 remain on. Thus, after
receiving an activation signal during a listen mode, the output
module 470 may continue to output an activation signal to the valve
110.
[0049] In one embodiment, the decoded control signal stored in the
latch module 450 is not changed until another control signal 230 is
received. For example, if the wireless receiver 220 receives an
activation control signal during a first listen mode, the output
module 470 generates outputs an appropriate activation signal to
the irrigation valve 110 during any remaining portion of the listen
mode and the subsequent sleep mode. If during the subsequent listen
phase the wireless receiver 220 does not receive a control signal
230, the content of the latch module 450 is not updated and the
state of the valve 110 is maintained until the failsafe period
lapses. As noted above, the failsafe period may include multiple
sleep and listen modes, such as 2, 5, 10, 15, 20, 30, 40, 50, 75,
or 100 sleep and listen modes. Thus, after providing a control
signal to the wireless receiver 220, the state of the valve may be
maintained for a long periods of time before another control signal
is necessary to maintain the desired state.
[0050] In one embodiment, the wireless receiver 220 does not have
sleep and listen modes and the wireless receiver 220 continuously
listens for received the control signal 230. Because continuous
operation of components of the wireless receiver 220 uses more
power than a wireless receiver 220 that only intermittently is in a
listen mode, a continuously powered wireless receiver may be most
advantageous in an embodiment where an AC power source is available
to the wireless receiver 220.
[0051] FIG. 4 is a flowchart illustrating an exemplary method of
operation for the wireless receiver 220. As noted above, in one
embodiment the wireless receiver 220 operates in two modes, a
listen mode and a sleep mode. In one embodiment, the mode of the
wireless receiver 220 is determined by a clock signal, such as the
asynchronous clock signal generated by clock 460. In other
embodiments, other circuitry, such as a counter/decoder or timer,
for example, may be used to determine the mode of the wireless
receiver 220. As illustrated in FIG. 4, in a step 510, wireless
receiver 220 enters the listen mode and in a step 570, the wireless
receiver enters the sleep mode. The amount of time spent in each of
the listen and sleep modes are not specified in the flowchart of
FIG. 4, but may be adjusted, such as at a factory that manufactures
the wireless receiver, to the particular application in which the
wireless receiver 220 is used. In one embodiment, the sleep mode is
much longer than the listen mode, providing a wireless receiver
with reduced power consumption when compared to an always-on
wireless receiver.
[0052] In a block 510, the wireless receiver 220 enters the listen
mode. In one embodiment, a clock signal is received by the wireless
receiver and is used to determine when the wireless receiver 220
should be in the listen mode. In the listen mode, the components of
the wireless receiver 220 that receive wireless control signals 230
are activated and listening for the control signals 230.
[0053] In a block 520, the wireless receiver 220 determines if a
control signal 230 has been received. If a control signal 230 is
not detected during the listen mode, the method continues to a
decision block 530. If a control signal 230 is detected during the
listen mode, the method continues to a block 534.
[0054] In the decision block 530, the latch module 450, for
example, determines if the failsafe period has lapsed. If the
failsafe period has lapsed, the method continues to a block 532
wherein the latch module 450 is update with data indicating a
default status for the valve. For example, the default status may
be either to maintain the irrigation valve 110 in its current
state, e.g., activated or deactivated, to activate the irrigation
valve 110, or to deactivate the irrigation valve 110. In an
embodiment where loss of signal is likely and water conservation is
important, the default status may be to deactivate the irrigation
valve 110 when the failsafe period has lapsed. Accordingly, after
the irrigation valve 110 has been activated by the reception of an
activation control signal, if another activation control signal is
not received within the failsafe period, the valve 110 will be
disabled. After setting the latch status to the default value in
block 532, the method continues to a block 570 where the wireless
receiver enters the sleep mode. As noted above, the timing for
entering the listen and sleep modes may be determined by a clock
that is configured to alternate the wireless receiver 220 between
the two modes according to predetermined time periods.
[0055] If it is determined in decision block 530 that the failsafe
period has not lapsed, the method continues to block 570 where the
wireless receiver 220 enters the sleep mode. In the embodiment of
FIG. 4, if the failsafe period has not lapsed, the status
information stored in the latch module 450 will not be changed and
the valve 110 will be maintain in its current state.
[0056] If a control signal has been received by the wireless
receiver 220 in block 520, the method continues to a block 534
where the failsafe period is reset. Thus, the time period in which
another control signal 230 must be received in order to update the
valve status stored in the latch module 450 is restarted. In one
embodiment, the failsafe period comprises about 17 listen and sleep
cycles.
[0057] Continuing to a block 540, a status indicator in the
wireless control signal 230 is determined. In one embodiment, a
decode module 420 is used to decode the received control signal 230
and determine a status indicator contained in the control signal
230. In one embodiment, the status indicator indicates whether the
irrigation valve 110 should be activated or deactivated. In other
embodiments, the control signal may also indicate the current
status for other irrigation valves. Accordingly, the decode module
420 may be configured to decode status information related to other
irrigation valves and select the appropriate status information for
the irrigation valve 110.
[0058] If the status indicator in the received control signal 230
indicates that the valve 110 should be activated, the method
continues to a block 530 where the status information stored in the
latch module 450 is updated to indicate that an activate signal has
been received. Conversely, if the received control signal 230
indicates that the valve 110 should be deactivated, the method
continues to block 550 where the status information stored in the
latch module 450 is updated to indicate that a deactivate signal
has been received. Thus, in either case, the latch module 450
contains the desired current status of the irrigation valve 110. As
noted above, the status contained in the latch module 450 will be
applied to the irrigation valve 110 not only during any remaining
time in the listen mode, but also through the duration of the sleep
mode.
[0059] After determining the content of the received control signal
230 and setting the status information in the latch module 450, the
method continues to a block 570 where the wireless receiver 220
enters the sleep mode. As discussed above, during the sleep mode,
certain circuitry of the wireless receiver 220 may be disabled or
set to low-power modes.
[0060] Moving to a block 580, the non-sleeping circuitry of the
wireless receiver 220 outputs a signal to the irrigation valve 110
according to the status information in the latch module 450. For
example, if the status information in the latch module 450 is set
to activate the irrigation valve 110, the wireless receiver outputs
a signal having a voltage level, current level, and polarity for a
period of time that causes the irrigation valve 110 to activate.
Alternatively, if the status information in the latch module 450 is
set to deactivate the irrigation valve 110, the wireless receiver
outputs a signal having a voltage level, current level, and
polarity for a period of time that causes the irrigation valve 110
to deactivate.
[0061] In one embodiment, block 580 occurs prior to block 570. In
this embodiment, the wireless receiver 220 outputs a signal to the
irrigation valve 110 according to the status information in the
latch module 450 prior to entering the sleep mode.
[0062] After completing the sleep mode, as indicated by the clock
460, the method returns to block 510, returning to the list
mode.
[0063] FIG. 5 is a timing diagram illustrating an exemplary output
signal from the wireless irrigation adapter 210 and of a signal
received by an exemplary irrigation valve 110 from a wireless
receiver 220. The timing diagram is divided into six time periods
t.sub.0 to t.sub.6.
[0064] In one embodiment, each of the time periods are equivalent,
such as 1, 10, 20, 30, 40, or 50 seconds, or 1, 2, 3, 4, 5, 10, 20,
30 or 60 minutes, for example. In other embodiments, the time
periods may be any other amount of time. As illustrated in FIG. 5,
the wireless irrigation adapter 210 outputs an activation control
signal during two time periods 610. As noted above with respect to
FIG. 2, the wireless irrigation adapter 210 may be configured to
periodically transmit the wireless control signal 230. For example,
the output of the wireless irrigation adapter 210 may have a 25%
duty cycle, wherein the control signal 230 is transmitted only 25%
of the time. In one embodiment, a length of time for each
transmission of the control signal 230 is set to a time period that
is longer than a combined sleep and listen mode of the wireless
receiver 220. Thus, no matter when the control signal 230 is
transmitted, the wireless receiver 220 will receive the control
signal 230, assuming the control signal 230 is not damaged,
obstructed or otherwise prevented from reaching the wireless
receiver 220.
[0065] In the embodiment of FIG. 5, the wireless receiver 220
repeatedly changes between listen and sleep modes. In the
embodiment of FIG. 5, the listen mode is about 1/9 the duration of
the sleep mode. Accordingly, at least some of the components of the
wireless receiver 220 are deactivated, or in a low-power mode, most
of the time. In other embodiments, the ratio of time distributed to
the listen and sleep modes are varied according to the particular
application. During the time 620, the wireless receiver 220
receives the control signal 230 transmitted by the wireless
irrigation adapter 210. In the embodiment of FIG. 5, the control
signal 610 indicates that the valve 110 should be activated. Upon
receiving the control signal 610, the wireless receiver 220 causes
the irrigation valve 110 to be activated.
[0066] Advantageously, at time 621 when the wireless receiver 220
returns to the sleep mode, the valve 110 remains in the activated
state through the use of a latch module, such as described above
with respect to FIG. 3. In one embodiment, the latch module 450
comprises one or more latching mechanisms, such as registers, one
shots, latches, set and hold circuits, or flip-flops, for example.
In one embodiment, the latch module 450 not only holds the state of
the valve during the sleep mode, but for a predetermined time
period that comprises multiple sleep and listen modes. For example,
the latch module 450 may be configured to hold the valve state in
the decoded control signal 421 for 10, 20, 30, 40, 50, or 100, for
example, cycles of listen and sleep modes. Thus, if the control
signal 230 is interrupted or obstructed after been received during
a single listen mode of the wireless receiver 220, the latch module
450 maintains its outputs and, thus, maintains a state of the
irrigation valve 110 for the predetermined failsafe period.
{(Russell, actually, the example I gave you used the DC-Latching
solenoid valves to remember the ACTIVATE/DEACTIVATE command. My
latch module actually required a lost signal to reset the latch
during the signal loss (gated in the listen-window), and only when,
and if, the signal was reacquired, then the failsafe period would
be reset by the signal reacquisition, but the system would "coast"
through a fairly long period without signal (17 seconds). As long
as the signal returned before the failsafe time-out, then the
system would operate almost as though signal had been there all
along (except for the opposite-state, response latency that this
system could introduce to the valve activation or deactivation, as
a result of the controller having switched command outputs during
the signal loss period. If signal loss never occurred, then that
latency would be reduced to just the period of one sleep interval,
plus a little listen period, plus signal propagation time.)}
[0067] In the example of FIG. 5, the latch module 450 is configured
to hold the decoded control signal 421 for a failsafe period that
is longer than at least three sleep and listen cycles, assuming
there is not an additional control signal 230 received. With
reference to FIG. 5, during the listen modes 630, 640, and 650, the
wireless irrigation adapter 210 is not transmitting the activation
control signal 610 and, accordingly, the wireless receiver 220 does
not receive a control signal 230. However, due to the use of the
latch module 450, the state of the valve remain activated during
these periods of non-transmission by the wireless irrigation
adapter 210 because the failsafe period is longer than three sleep
and listen cycles.
[0068] During the listen mode 660, the wireless receiver 220 again
receives the activation control signal 610 and, accordingly,
latches the decoded control signal 421 into the latch module 450
and resets failsafe period.
[0069] Because the wireless irrigation adapter 210 is configured to
transmit the wireless control signal 230 only periodically, the use
of radio frequency bands, such as the UHF band, may be reduced.
Accordingly, in this embodiment, the wireless irrigation adapter
210 does not overuse the radio frequency at which it transmits the
wireless control signals 230.
[0070] FIG. 6 is a block diagram illustrating exemplary components
of the decode module 420, latch module 450, and output module 470
of FIG. 3. The components illustrated in FIG. 6 are exemplary only
and are not intended to limit possible configurations of components
in the wireless receiver 220.
[0071] In the embodiment of FIG. 6, the decode module 420 comprises
a receiving module 710 and a decoder 720. In one embodiment, the
receiving module 710 is a digitally coded receiving module that
provides a coded output, wherein the output of the receiving module
710 is a unique combination of bits. In one embodiment, when the
receiving module 710 does not receive a control signal 230 from the
antenna 705, the receiving module does not provide an output signal
to the decoder 720. In another embodiment, when the receiving
module 710 does not receive a control signal 230 from the antenna
705, a receiving module outputs a signal to the decoder 720
indicating that a control signal has not been received, such as a
null output including all zeros. As noted in FIG. 2, the clock 330
controls when the decode module 420 actively listens for wireless
control signals 230. During a sleep mode, the receiving module 710
may enter an ultra low power standby mode. The receiving module 710
may be awakened from the sleep mode by the state of a clock signal,
or a transition therefrom, indicating the beginning of the listen
mode. Because the receiving module 710 requires some time to power
on and accurately output any received control signal 230, the
duration of the listen mode is advantageously long enough to allow
accurate recognition of the control signal 230
[0072] In one embodiment, the decoder is trailing edge triggered by
the clock signal output from the clock 330, and is configured to
decode the output of the receiving module 710 and output the
decoded signal to the latch module 450. In one embodiment, the
output of the receiving module 710 is a four bit binary code and
the decoder 720 converts the 4-bit binary code into a 3-bit decoded
output 722.
[0073] The latch 730 comprises any circuit, or combination of
circuits, that are capable of storing digital data for a
predetermined period of time. For example, in one embodiment, the
latch 730 stores the decoded output 722 during the sleep mode of
the wireless receiver 220. In one embodiment, the decoded output
722 is registered in the latch at the trailing edge of the listen
mode clock signal, and the decoded output 722 remains unchanged in
the latch 730 until the subsequent trailing edge of the listen
mode. When the subsequent listen mode completes, the current
decoded output 722 is latched into the latch 730.
[0074] In the embodiment of FIG. 6, a signal loss one-shot 740 is
configured to maintain the state of the irrigation valve 110 during
the failsafe period when a listen mode lapses without receiving a
control signal 230. In one embodiment the signal loss one-shot 740
is set to hold a received digital signal for a failsafe period,
such as 1, 5, 10, 15, 20, 30, or 60 seconds, for example. In one
embodiment, a RC network is used to set the timing of the one-shot
740. Thus, the hold time of the signal loss one-shot 740 may be
determined by changing the values of the resistor and capacitor in
the corresponding RC network. A digital counter could also be used
for this purpose. Those of skill in the art will recognize that
various other electrical components alone, and in combination, may
be used in order to provide similar functionality.
[0075] In the embodiment of FIG. 6, a first output of the signal
loss one-shot 740 is electrically coupled to an activation one-shot
760 and a second output of the signal loss one-shot 740 is
electrically coupled to a deactivation one-shot 750. In one
embodiment, the one-shot 740 comprises a CMOS, resettable,
retriggerable, monostable multivibrator with Schmidt triggered
inputs. When the signal loss one-shot 740 is within the failsafe
period, the first output to the activation one-shot 760 is
asserted. After the failsafe period has lapsed, the second output
to the deactivation one-shot 750 is asserted. As described in
further detail below, the combination of the activation one-shot
760 and the activation driver transistor 770 maintain a state of
the irrigation valve 110 during the failsafe period. Likewise,
after the failsafe time period has elapsed, the deactivation
one-shot 750 and the deactivation driver transistor circuit 780
generate a deactivation signal to the irrigation valve solenoid,
thus deactivating the irrigation valve 110.
[0076] In60 embodiments where the valves 110 comprise DC-latching
solenoids, the valves 110 may only receive an output from the
output module 470 when the state of the valve 220 needs to be
changed. Thus, in this embodiment, so long as a control signal 230
indicating that a particular valve 110 should be activated
continues to be received by the wireless receiver, the output
module 470 is not required to output an electrical signal to the
valve 110 in order to maintain its state, after the valve has
initially been activated. Similarly, in this embodiment, a single
deactivation signal will change the state of the DC-latching
solenoid in the valve 110 so that the valve is closed, and remains
closed until an activation signal is received. Thus, the use of a
DC-latching solenoid may reduce the power requirements and extend
the battery life of a wireless receiver.
[0077] The combination of the activation one-shot 760 and the
activation driver transistor circuit 770 generate an electrical
pulse that is sufficient to activate the irrigation valve 110. As
noted above, in an advantageous embodiment, the irrigation valve
110 comprises a DC latching solenoid that may be activated by a DC
pulse of a first polarity and deactivated by a DC pulse of an
opposite polarity. In other embodiments, a DC pulse of varying
voltage and/or current levels may be used to activate and
deactivate the irrigation valve 110. Advantageously, DC latching
solenoid valves do not draw quiescent current while in the
activated or deactivated states that follow the control signal
pulse. They only draw current while they are being switched from
the activate mode to the deactivated mode and back again.
[0078] In one embodiment, the activation one-shot 760 comprises an
RC circuit with components selected to create a pulse output of
about 100 ms. In other embodiments, the pulse may be longer or
shorter than 100 ms. In an advantageous embodiment, the pulse
length is selected to be long enough to reliably activate the
irrigation valve 110, but not long enough to damage the irrigation
valve 110. Because the irrigation valve 110 may be activated by a
short pulse, the power required to activate the irrigation valve
110 is minimized. In one embodiment, the activation driver
transistor 770 comprises circuitry that generates considerable
current that is delivered to the coil of the solenoid of the
irrigation valve 110 when the activation one-shot 760 outputs a
pulse. In one embodiment, the activation driver transistor 770
comprises one or more MOSFETS.
[0079] The deactivation one-shot 750 and the deactivation driver
transistor 780 operate in a similar manner to the activation
one-shot 760 and the activation driver transistor 770,
respectively. When an input signal to the deactivation one-shot 750
is asserted, the deactivation one-shot generates an output pulse
for a predetermined time period, such as 100 ms, for example. When
this output pulse is received by the activating driver transistor
770, the deactivating driver transistor 780 generates and outputs a
high current DC pulse to the coil of the irrigation valve 110,
causing the irrigation valve 110 to deactivate.
[0080] In one embodiment, the activation one-shot 760 and the
activation driver transistor 770 are powered by a first battery,
such as a 9 V battery, while the deactivation one-shot 760 and be
the activation driver transistor 780 are powered by a second
battery such as a second 9 V battery.
[0081] In the embodiment of FIG. 6, the decode module 420, latch
module 450, and output module 470 are shown controlling only a
single irrigation valve 110. However, in another embodiment, the
received control signal 230 may include status information for
multiple irrigation valves 110. In such an embodiment, the decoder
720 may be configured to output a decoded digital signal
corresponding with each of the irrigation valves 110 and the latch
module 340 may contain multiple sets of one-shots 740, 750 and
driver transistors 770, 780 for each irrigation valve 110.
[0082] The foregoing description details certain embodiments of the
invention. It will be appreciated, however, that no matter how
detailed the foregoing appears in text, the invention can be
practiced in many ways. As is also stated above, it should be noted
that the use of particular terminology when describing certain
features or aspects of the invention should not be taken to imply
that the terminology is being re-defined herein to be restricted to
including any specific characteristics of the features or aspects
of the invention with which that terminology is associated. The
scope of the invention should therefore be construed in accordance
with the appended claims and any equivalents thereof.
* * * * *