SYSTEM AND METHOD FOR OCCUPANCY SENSING USING ADJUSTABLE DETECTION AND LOAD CONTROL PROFILE

• US 20160126733A1
• Filed: 11/03/2014
• Published: 05/05/2016
• Est. Priority Date: 11/03/2014
• Status: Active Grant

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Hick, Robert L., Leinen, Richard A.
• Granted Patent: US 9,880,534 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/13 by using passive infrared detectors
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An occupancy sensor is disclosed including a passive infrared (PIR) sensing element, a temperature sensing element, and a processor. The processor receives temperature signals from the temperature sensing element and configures the occupancy sensor into a selected operating mode based the received temperature signal. The operating mode may be associated with a predetermined sensing threshold of the PIR sensing element. The processor controls an associated load based on the selected operating mode and the received occupancy signals. The occupancy sensor can alternatively include an occupancy sensing element and a photodetector. Based on the amount of light detected by the photodetector over time, the occupancy sensor can calculate a rough estimate of time of day, and can automatically adjust one or more sensing and/or operational characteristics based on that time of day determination. A photosensor may implement daylight harvesting based on different light levels associated with different times of day.

Claims

1. An occupancy sensor, comprising:

a passive infrared (PIR) sensing element;

a temperature sensing element; and

a processor coupled to the PIR sensing element and the temperature sensing element, the processor configured to receive temperature signals from the temperature sensing element and to configure the occupancy sensor into a selected one of a plurality of operating modes based on the received temperature signals;

the processor further configured to receive occupancy signals from the PIR sensing element and to control an associated load based on the selected operating mode and the received occupancy signals.

2. The occupancy sensor of claim 1, wherein the processor associates each of the plurality of operating modes with at least one of:

a different sensing threshold of the PIR sensor, a different sensing threshold of the temperature sensing element, and a different time delay before turning off the associated load.

3. The occupancy sensor of claim 1, wherein the processor is programmed to compare the received temperature signals to a first stored threshold value and to configure the occupancy sensor into a first operating mode when the received temperature signals exceed the first stored threshold value.

4. The occupancy sensor of claim 3, wherein the processor is programmed to compare the received temperature signals to a second stored threshold value and to configure the occupancy sensor into a second operating mode when the received temperature signals exceed the second stored threshold value, wherein the second stored threshold value is greater than the first stored threshold value.

5. The occupancy sensor of claim 4, wherein when the occupancy sensor is in the first operating mode a first sensing threshold is associated with the PIR sensor, and wherein when the occupancy sensor is in the second operating mode a second sensing threshold is associated with the PIR sensor, wherein the first sensing threshold is different than the second sensing threshold.

6. The occupancy sensor of claim 1, wherein each of the plurality of operating modes is associated with a preselected sensing threshold associated with the PIR sensor, at least two operating modes of the plurality of operating modes having a different preselected sensing threshold.

7. The occupancy sensor of claim 6, wherein a first operating mode of the plurality of operating modes is associated with temperature signals that exceed a first predetermined value, and a second operating mode of the plurality of operating modes is associated with temperature signals that exceed a second predetermined value, the first predetermined value representative of a first ambient temperature, the second predetermined value representative of a second ambient temperature, the first ambient temperature lower than the second ambient temperature.

8. The occupancy sensor of claim 1, further comprising a memory associated with the processor, the memory for storing first and second predetermined values associated with the selected operating mode.

9. The occupancy sensor of claim 1, further comprising a photodetector coupled to the processor, the processor executing instructions for:

receiving an ambient light level signal from the photodetector, the ambient light level signal representative of an ambient light level in a monitored area,

comparing the ambient light level signal to a first predetermined lighting level associated with a first time period, the first time period associated with a time of day, and

controlling the associated load based on the comparison.

10. The occupancy sensor of claim 9, wherein when the ambient light level signal is below the first predetermined lighting level during the first time period, controlling the associated load comprises increasing a brightness of the associated load until the ambient light level signal is substantially equal to the first predetermined lighting level.

11. The occupancy sensor of claim 9, wherein when the ambient light level signal is above the first predetermined lighting level during the first time period, controlling the associated load comprises decreasing a brightness of the associated load until the ambient light level signal is substantially equal to the first predetermined lighting level.

12. An occupancy sensor, comprising:

an occupancy sensing element;

a photodetector; and

a processor coupled to the occupancy sensing element and the photodetector, the processor configured to receive light signals from the photodetector and to configure the occupancy sensor into at least one of a plurality of operating modes based on an estimated time of day, the estimated time of day determined by the processor based on selected ones of said light signals received from the photodetector;

wherein the processor is configured to receive occupancy signals from the occupancy sensing element and to control an associated load based on the selected operating mode and the received occupancy signals.

13. The occupancy sensor of claim 12, wherein the processor associates each of the plurality of operating modes with at least one of:

a different sensing threshold of the PIR sensor, a different sensing threshold of the temperature sensing element, and a different time delay before turning off the associated load.

14. The occupancy sensor of claim 12, a first operating mode of the plurality of operating modes being selected by the processor when the light signals from the photodetector are determined by the processor to be associated with a first lighting level associated with a first predetermined time of day;

wherein when in the first operating mode the load is not energized regardless of whether the processor receives occupancy signals from the occupancy sensing element.

15. The occupancy sensor of claim 14, a second operating mode of the plurality of operating modes being selected by the processor when the light signals from the photodetector are determined by the processor to be associated with a second lighting level associated with a second predetermined time of day that is different from said first predetermined time of day;

wherein when in the second operating mode the load is energized when the processor receives occupancy signals from the occupancy sensing element, the load being maintained in the energized state for a first predetermined time period.

16. The occupancy sensor of claim 15, a third operating mode of the plurality of operating modes being selected by the processor when the processor determines, based on the estimated time of day, that a third predetermined time of day has been reached, the third predetermined time of day being different from the first and second predetermined times of day;

wherein in the third operating mode the load is energized when the processor receives occupancy signals from the occupancy sensing element, the load being maintained in an energized state for a second predetermined time period, the first predetermined time period being greater than the second predetermined time period.

17. The occupancy sensor of claim 12, wherein the estimated time of day is determined by the processor as being the midpoint time between a sunrise state and a sunset state, the sunrise state associated with a first light threshold value and the sunset state associated with a second light threshold value, the processor determining the sunrise state when light signals received from the photodetector indicate an ambient light level greater than the first light threshold value, the processor determining the sunset state when light signals from the photodetector indicate an ambient light level greater than the second light threshold value.

18. The occupancy sensor of claim 17, further comprising a memory associated with the processor, the memory for a sunrise time associated with said sunrise time, a sunset time associated with said sunset time, the midpoint time and the predetermined time of day.

19. The occupancy sensor of claim 12, wherein the occupancy sensing element is RF, PIR, ultrasonic, acoustic or video elements, and combinations thereof.

20. A method for controlling a load with an occupancy sensor, the method comprising:

at a PIR sensor, identifying an occupied condition of a monitored area and sending an occupancy signal to a processor;

at a temperature sensing element, identifying an ambient temperature of the monitored area and sending a temperature signal to the processor representative of said ambient temperature;

at the processor, receiving the temperature signal and configuring the occupancy sensor into a selected one of a plurality of operating modes based thereon; and

controlling a load associated with the monitored area based on the selected operating mode and the occupancy signal;

wherein the selected operating mode is associated with a predetermined sensing threshold associated with the PIR sensor.

21. The method of claim 20, wherein configuring the occupancy sensor into a selected one of a plurality of operating modes comprises comparing the temperature signal to a first stored threshold value and configuring the occupancy sensor into a first operating mode when the temperature signals exceed the first stored threshold value.

22. The method of claim 21, wherein configuring the occupancy sensor into a selected one of a plurality of operating modes comprises comparing the temperature signals to a second stored threshold value and configuring the occupancy sensor into a second operating mode when the temperature signals exceed the second stored threshold value.

23. The method of claim 20, wherein when the occupancy sensor is in a first operating mode of the plurality of operating modes a first sensing threshold is associated with the PIR sensor, and wherein when the occupancy sensor is in a second operating mode of the plurality of operating modes a second sensing threshold is associated with the PIR sensor, wherein the first sensing threshold is different than the second sensing threshold.

24. The method of claim 20, wherein each of the plurality of operating modes is associated with a preselected sensing threshold associated with the PIR sensor, at least two operating modes of the plurality of operating modes having a different preselected sensing threshold.

25. A method for controlling a load with an occupancy sensor, the method comprising:

at an occupancy sensing element, identifying an occupied condition of a monitored area and sending an occupancy signal to a processor;

at a photodetector, identifying an ambient light level of the monitored area and sending a light signal to the processor representative of said ambient light level;

at the processor, receiving the light signals from the photodetector and configuring the occupancy sensor into at least one of a plurality of operating modes based on an estimated time of day, the estimated time of day determined by the processor based on selected ones of said light signals received from the photodetector; and

controlling a load associated with the monitored area based on the selected operating mode and the occupancy signal.

26. The method of claim 25, wherein configuring the occupancy sensor into at least one of a plurality of operating modes comprises configuring the occupancy sensor into a first operating mode when the light signals from the photodetector are determined to be associated with a first predetermined time of day;

and

wherein when in the first operating mode the load is not energized regardless of whether the occupancy signal is received from the occupancy sensing element.

27. The method of claim 26, wherein configuring the occupancy sensor into at least one of a plurality of operating modes comprises configuring the occupancy sensor into a second operating mode when the light signals from the photodetector are determined to be associated with a second predetermined time of day that is different from said first predetermined time of day;

and

wherein when in the second operating mode the load is energized when the processor receives occupancy signals from the occupancy sensing element, the load being maintained in the energized state for a first predetermined time period.

28. The method of claim 27, wherein configuring the occupancy sensor into at least one of a plurality of operating modes comprises configuring the occupancy sensor into a third operating mode when the processor determines, based on the estimated time of day, that a predetermined time of day has been reached;

wherein in the third operating mode the load is energized when the processor receives occupancy signals from the occupancy sensing element, the load being maintained in an energized state for a second predetermined time period, the first predetermined time period being greater than the second predetermined time period.

29. The method of claim 28, further comprising, at the processor, determining the estimated time of day as the midpoint time between a sunrise state and a sunset state, the sunrise state associated with a first light threshold value and the sunset state associated with a second light threshold value, the processor determining the sunrise state when light signals received from the photodetector indicate an ambient light level greater than the first light threshold value, the processor determining the sunset state when light signals from the photodetector indicate an ambient light level greater than the second light threshold value.