Battery-powered occupancy sensor

• US RE47,511 E1
• Filed: 10/19/2015
• Issued: 07/09/2019
• Est. Priority Date: 09/03/2008
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Technology Company LLC
• Inventors: Blakeley, Matthew Robert, Steiner, James P., Schrems, Adam J.
• Primary Examiner(s): Worjloh, Jalatee
• Application Number:
  US14/873,806
• Time in Patent Office: 1,359 Days
• Field of Search: 3405391, 340541, 3406936
• CPC Class Codes: N/A

Abstract

A load control system comprises a load control device and a battery-powered occupancy sensor, which transmits a first wireless signal to the load control device in response to detecting the presence of an occupant in a space. The load control system further comprises a visual indicator for providing a visual indication when the magnitude of a battery voltage of a battery of the occupancy sensor has dropped below a predetermined low-battery voltage threshold. The occupancy sensor may comprise the visual indicator, such that the visual indicator is illuminated when the occupancy detects the presence of the occupant in the space and the magnitude of the battery voltage is less than the predetermined threshold. Alternatively, the load control device may comprise the visual indicator, such that the visual indicator is illuminated in response to receiving a second wireless signal, which is transmitting by the occupancy sensor when the magnitude of the battery voltage is less than the predetermined threshold.

Claims

1. A load control system for controlling the amount of power delivered from an AC power source to an electrical load in a space in response to detecting the presence or absence of an occupant in the space, the system comprising:

2. The system of claim 1, wherein the occupancy sensor comprises the visual indicator, the visual indicator coupled to the controller, such that the controller is operable to controllably illuminate the visual indicator in response to the detector circuit detecting the occupancy condition if the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

3. The system of claim 2, wherein the controller blinks the visual indicator in response to the detector circuit detecting the presence of the occupant in the space if the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

4. The system of claim 2, wherein the controller only illuminates the visual indicator for a predetermined period of time when the occupancy detector first detects the presence of the occupant in the space.

5. The system of claim 2, wherein the occupancy sensor does not transmit any wireless control signals when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

6. The system of claim 2, wherein the occupancy sensor further comprises an actuator coupled to the controller, such that the controller is responsive to actuations of the actuator when the magnitude of the battery voltage is greater than or equal to the predetermined low-battery voltage threshold, the controller not responsive to actuations of the actuator when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

7. The system of claim 2, wherein the occupancy detector circuit of the occupancy detector comprises an infrared detector responsive to infrared energy representative of the presence or absence of the occupant in the space, the occupancy detector further comprising a lens positioned to direct the infrared energy from the space to the infrared detector, and a light-emitting diode positioned to illuminate the lens, the light-emitting diode coupled to the controller, such that the controller is operable to controllably illuminate the light-emitting diode, the controller operable to illuminate the light-emitting diode to illuminate the lens in response to the detector circuit detecting the presence of the occupant in the space if the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

8. The system of claim 1, wherein the load control device comprises the visual indicator, the occupancy sensor operable to transmit a second wireless signal to the load control device in response to determining that the magnitude of the battery voltage has dropped below the predetermined low-battery voltage threshold, the load control device operable to illuminate the visual indicator in response to receiving the second wireless signal from the occupancy sensor.

9. The system of claim 8, wherein the load control device blinks the visual indicator in response to receiving the second wireless signal.

10. A wireless occupancy sensor for detecting the presence or absence of an occupant in a space, the sensor comprising:

11. The sensor of claim 10, wherein the controller blinks the visual indicator for a predetermined time period in response to the detector circuit detecting the presence of the occupant in the space if the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

12. The sensor of claim 10, wherein the detector circuit comprises an infrared detector responsive to infrared energy representative of the occupancy condition in the space, the sensor further comprising:

13. The sensor of claim 10, further comprising

14. A method of controlling the amount of power delivered from an AC power source to an electrical load located in a space, the method comprising the steps of:

15. The method of claim 14, wherein the occupancy sensor further comprises a visual indicator and the step of providing a visual indication comprises illuminating the visual indicator in response to determining that the magnitude of the first battery voltage has dropped below the predetermined low-battery voltage threshold.

16. The method of claim 15, wherein the step of providing a visual indication comprises blinking the visual indicator for a predetermined time period in response to determining that the magnitude of the first battery voltage has dropped below the predetermined low-battery voltage threshold.

17. The method of claim 15, wherein the occupancy sensor does not transmit any wireless control signals when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

18. The method of claim 15, wherein the step of providing a visual indication comprises only illuminating the visual indicator when the magnitude of the first battery voltage is below the predetermined low-battery voltage threshold and the occupancy detector detects the presence of the occupant in the space.

19. The method of claim 14, further comprising the step of:

20. The method of claim 19, wherein the step of providing a visual indication comprises blinking the visual indicator of the load control device in response to the load control device receiving the second wireless signal.

21. A load control system for controlling the amount of power delivered from an AC power source to an electrical load in a space in response to detecting the presence or absence of an occupant in the space, the system comprising:

a load control device adapted to be coupled in series electrical connection between the AC power source and the electrical load for control of the amount of power delivered to the electrical load, the load control device operable to receive wireless control signals and to control the amount of power delivered to the electrical load in response to the wireless control signals;

an occupancy sensor positioned remote from the load control device, and comprising a controller, an occupancy detector circuit for detecting the presence or absence of the occupant in the space and a wireless transmitter for transmitting a first wireless occupied-take-action control signal to the load control device in response to the occupancy detector circuit detecting the presence of the occupant in the space, the load control device operable to enable the delivery of power to the electrical load in response to the first wireless occupied-take-action control signal, the occupancy sensor further comprising a battery for powering the controller and the wireless transmitter, the controller operable to monitor the magnitude of a battery voltage of the battery; and

a visual indicator for providing a visual indication when the magnitude of the battery voltage has dropped below a predetermined low-battery voltage threshold,

the occupancy sensor further comprising an ambient light detector coupled to the controller, the controller configured to compare a level of ambient light in the space detected by the ambient light detector to an ambient light threshold;

the occupancy sensor having a low-battery operating mode wherein the controller is configured to halt a normal mode of operation of the occupancy sensor to conserve battery power when the magnitude of the battery voltage has dropped below the predetermined low-battery voltage threshold,

the occupancy sensor remaining operable in the low-battery operating mode;

further wherein the controller is configured in the normal mode of operation to transmit both the first wireless occupied-take-action control signal and a first wireless occupied-no-action control signal, wherein the first wireless occupied-take-action control signal informs the load control device that the space is occupied and commands the load control device to take action because the ambient light level is below the ambient light threshold, and the first wireless occupied-no-action control signal informs the load control device that the space is occupied and commands the load control device to take no action because the ambient light level is above the ambient light threshold,

wherein the load control device comprises an electrical device controller configured;

to determine whether the first wireless occupied-take-action control signal has been received, and in response to determining that the first wireless occupied-take-action control signal has been received, to register the occupancy sensor as being in an occupied state and to turn on the electrical load; and

to determine whether the first wireless occupied-no-action control signal has been received, and in response to determining that the first wireless occupied-no-action control signal has been received, to register the occupancy sensor as being in an occupied state and to maintain the electrical load in its last condition by leaving the electrical load on when the electrical load is on and leaving the electrical load off when the electrical load is off,

wherein the controller is configured to prevent transmission of the first wireless occupied-take-action control signal and the first wireless occupied-no-action control signal in the low-battery operating mode,

the occupancy sensor further comprising an occupancy timer that times-out a predetermined time-out period after the occupancy sensor determines the space is unoccupied, the controller being configured upon expiration of the time-out period to change to a vacant state and to determine whether the magnitude of the battery voltage has dropped below the low-battery voltage threshold and if it has not, to transmit a wireless vacant command to the load control device and if it has, not to transmit the wireless vacant command;

further wherein the load control device comprises a failsafe timer, the failsafe timer being started when the wireless occupied-take-action control signal or the wireless occupied-no-action control signal is received from the occupancy sensor, the failsafe timer timing-out after a failsafe period when no wireless occupied-take-action and no wireless occupied-no-action control signal is received during the failsafe period from the occupancy sensor, the time-out of the failsafe timer causing the load control device to turn off the electrical load and to identify the occupancy sensor as vacant.

22. The system of claim 21, wherein the occupancy sensor comprises the visual indicator, the visual indicator coupled to the controller, the controller being configured to controllably illuminate the visual indicator in response to detection by the detector circuit of the occupancy condition when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

23. The system of claim 22, wherein the controller is configured to blink the visual indicator in response to detection by the detector circuit of the presence of the occupant in the space when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

24. The system of claim 22, wherein the controller is configured to illuminate the visual indicator for a predetermined period of time only in response to a first detection by the occupancy detector of the presence of the occupant in the space.

25. The system of claim 22, wherein the occupancy sensor does not transmit any wireless control signals when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

26. The system of claim 22, wherein the occupancy sensor further comprises an actuator coupled to the controller, the controller responsive to actuations of the actuator when the magnitude of the battery voltage is greater than or equal to the predetermined low-battery voltage threshold, the controller not responsive to actuations of the actuator when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

27. The system of claim 22, wherein the occupancy detector circuit of the occupancy detector comprises an infrared detector responsive to infrared energy representative of the presence or absence of the occupant in the space, the occupancy detector further comprising a lens positioned to direct the infrared energy from the space to the infrared detector, and a light-emitting diode positioned to illuminate the lens, the light-emitting diode coupled to the controller, the controller configured to controllably illuminate the light-emitting diode, the controller configured to illuminate the light-emitting diode to illuminate the lens in response to detection by the detector circuit of the presence of the occupant in the space when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

28. The system of claim 21, wherein the load control device comprises the visual indicator, the occupancy sensor configured to transmit a second wireless signal to the load control device in response to determining that the magnitude of the battery voltage has dropped below the predetermined low-battery voltage threshold, the load control device configured to illuminate the visual indicator in response to receiving the second wireless signal from the occupancy sensor.

29. The system of claim 28, wherein the load control device is configured to blink the visual indicator in response to receiving the second wireless signal.

30. A wireless occupancy sensor for detecting the presence or absence of an occupant in a space, the sensor comprising:

a detector circuit for detecting the presence or absence of the occupant in the space;

a controller coupled to the detector circuit, such that the controller is responsive to the detector circuit;

an ambient light detector coupled to the controller, the controller configured to compare a level of ambient light in the space detected by the ambient light detector to an ambient light threshold;

a wireless transmitter coupled to the controller for transmitting wireless signals;

a visual indicator coupled to the controller, such that the controller is operable to controllably illuminate the visual indicator; and

a battery for producing a battery voltage for powering the controller, the wireless transmitter, and the visual indicator;

wherein the controller is configured to monitor the magnitude of the battery voltage of the battery, the controller operable to transmit wireless signals in response to the detector circuit detecting the presence of the occupant in the space in a normal mode if the magnitude of the battery voltage is greater than or equal to a predetermined low-battery voltage threshold, the controller configured to enter a low-battery operating mode to conserve battery power when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold wherein the controller remains operable in the low-battery operating mode, the controller operable in the low-battery operating mode to illuminate the visual indicator in response to the detector circuit detecting the presence of the occupant in the space if the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold,

further wherein the controller is configured in the normal mode to transmit both a wireless occupied-take-action control signal and a wireless occupied-no-action control signal, wherein the wireless occupied-take-action control signal informs a load control device that the space is occupied and commands the load control device to take action because the ambient light level is below the ambient light threshold, and the wireless occupied-no-action control signal informs the load control device that the space is occupied and commands the load control device to take no action because the ambient light level is above the ambient light threshold;

wherein the controller is configured to prevent transmission of the wireless occupied-take-action control signal and the wireless occupied-no-action control signal in the low-battery operating mode,

the occupancy sensor further comprising an occupancy timer that times-out a predetermined time-out period after the occupancy sensor determines the space is unoccupied, the controller being configured upon expiration of the time-out period to change to a vacant state and to determine whether the magnitude of the battery voltage has dropped below the low-battery voltage threshold and if it has not, to transmit a wireless vacant command to the load control device and if it has, not to transmit the wireless vacant command,

wherein the occupancy sensor is positioned remote from the load control device;

further wherein the occupancy sensor is configured to operate with a load control device that comprises a failsafe timer, the failsafe timer being started when the wireless occupied-take-action control signal or the wireless occupied-no-action control signal is received from the occupancy sensor, the failsafe timer timing-out after a failsafe period when no wireless occupied-take-action and no wireless occupied-no-action control signal is received during the failsafe period from the occupancy sensor, the time-out of the failsafe timer causing the load control device to turn off the electrical load and to identify the occupancy sensor as vacant;

further wherein the occupancy sensor is configured to transmit, when in the low-battery operating mode, a failsafe disable message to the load control device instructing the load control device to disable the failsafe timer, such that the load control device does not turn off the electrical load at the end of the failsafe period when the occupancy sensor is in the low-battery operating mode.

31. The sensor of claim 30, wherein the controller is configured to blink the visual indicator for a predetermined time period in response to detection by the detector circuit of the presence of the occupant in the space when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

32. The sensor of claim 30, wherein the detector circuit comprises an infrared detector responsive to infrared energy representative of the occupancy condition in the space, the sensor further comprising:

an enclosure housing the detector circuit, the controller, the ambient light detector, the wireless transmitter, the visual indicator, and the battery;

a lens positioned to direct the infrared energy from the space to the infrared detector; and

a light-emitting diode positioned to illuminate the lens, the light-emitting diode coupled to the controller, the controller being configured to controllably illuminate the light-emitting diode;

wherein the lens and the light-emitting diode define the visual indicator, the controller configured to illuminate the light-emitting diode to illuminate the lens in response to detection by the detector circuit of the presence of the occupant in the space when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

33. The sensor of claim 30, further comprising:

an actuator coupled to the controller, the controller responsive to actuations of the actuator when the magnitude of the battery voltage is greater than or equal to the predetermined low-battery voltage threshold, the controller not responsive to actuations of the actuator when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold to conserve battery power.

34. A method of controlling by a load control device the amount of power delivered from an AC power source to an electrical load located in a space, the method comprising the steps of:

providing an occupancy sensor wherein the occupancy sensor is positioned remote from the load control device, and having a first battery, a controller, an occupancy detector circuit, an ambient light detector and a wireless transmitter;

powering the controller and the wireless transmitter with the first battery;

detecting the presence of an occupant in the space;

detecting with the ambient light detector the level of ambient light in the space and comparing the ambient light in the space to an ambient light threshold;

transmitting a first wireless signal in response to the step of detecting the presence or absence of an occupant in the space;

the step of transmitting including operating the controller in a normal mode of operation to transmit both a wireless occupied-take-action control signal and a wireless occupied-no-action control signal, wherein the wireless occupied-take-action control signal informs the load control device that the space is occupied and commands the load control device to take action because the ambient light level is below the ambient light threshold, and the wireless occupied-no-action control signal informs the load control device that the space is occupied and commands the load control device to take no action because the ambient light level is above the ambient light threshold,

maintaining by the load control device, in response to receiving the wireless occupied-no-action control signal, the electrical load in its last condition;

monitoring the magnitude of a first battery voltage of the first battery;

determining that the magnitude of the first battery voltage has dropped below a predetermined low-battery voltage threshold and entering a low-battery operating mode, and, in the low-battery operating mode, halting a normal mode of operation to conserve battery power with the controller remaining operable; and

providing, in the low-battery operating mode, a visual indication in response to determining that the magnitude of the battery voltage has dropped below the predetermined low-battery voltage threshold; and

preventing transmission of the wireless occupied-take-action control signal and the wireless occupied-no-action control signal in the low-battery operating mode;

further comprising providing an occupancy time-out period that expires a predetermined time after the occupancy sensor determines the space is unoccupied, and upon expiration of the time-out period;

changing to a vacant state; and

checking to determine if the magnitude of the battery voltage has dropped below the low-battery voltage threshold and if it has not, transmitting a wireless vacant command to the load control device, and if it has, not transmitting the wireless vacant command;

further comprising providing in the load control device a failsafe timer, starting the failsafe timer when the wireless occupied-take-action control signal or the wireless occupied-no-action control signal is received from the occupancy sensor, the failsafe timer timing-out after a failsafe period when no wireless occupied-take-action control signal and no wireless occupied-no-action control signal is received during the failsafe period from the occupancy sensor, the time-out of the failsafe timer causing the load control device to turn off the electrical load and to identify the occupancy sensor as vacant;

further comprising the occupancy sensor transmitting, when in the low-battery operating mode, a failsafe disable message to the load control device instructing the load control device to disable the failsafe timer, such that in response to receiving the failsafe disable message the load control device does not turn off the electrical load at the end of the failsafe period when the occupancy sensor is in the low-battery operating mode.

35. The method of claim 34, wherein the occupancy sensor further comprises a visual indicator and the step of providing a visual indication comprises illuminating the visual indicator in response to determining that the magnitude of the first battery voltage has dropped below the predetermined low-battery voltage threshold.

36. The method of claim 35, wherein the step of providing a visual indication comprises blinking the visual indicator for a predetermined time period in response to determining that the magnitude of the first battery voltage has dropped below the predetermined low-battery voltage threshold.

37. The method of claim 35, wherein the occupancy sensor does not transmit any wireless control signals when the magnitude of the battery voltage is less than the predetermined low-battery voltage threshold.

38. The method of claim 35, wherein the step of providing a visual indication comprises only illuminating the visual indicator when the magnitude of the first battery voltage is below the predetermined low-battery voltage threshold and the occupancy detector detects the presence of the occupant in the space.

39. The method of claim 34, further comprising the step of:

providing a load control device adapted to be coupled in series electrical connection between the AC power source and the electrical load for controlling the amount of power delivered to the electrical load, the load control device comprising a visual indicator;

transmitting a second wireless signal from the occupancy sensor to the load control device in response to determining that the magnitude of the first battery voltage has dropped below the predetermined low-battery voltage threshold;

wherein the step of providing a visual indication comprises illuminating the visual indicator of the load control device in response to the load control device receiving the second wireless signal.

40. The method of claim 39, wherein the step of providing a visual indication comprises blinking the visual indicator of the load control device in response to the load control device receiving the second wireless signal.