System and method for occupancy sensing using adjustable detection and load control profile

Patent metadata

Field	Value
Publication number	US-2016126733-A1
Application number	US-201414530891-A
Country	US
Kind code	A1
Filing date	Nov 3, 2014
Priority date	Nov 3, 2014
Publication date	May 5, 2016
Grant date	—

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.

First claim

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 ligh

Assignees

• Leviton Manufacturing Co

Inventors

• Hick Robert L
• Leinen Richard A

Classifications

• H05B47/11

  by determining the brightness or colour temperature of ambient light · CPC title

• G05B15/02 Primary

  electric · CPC title

• H02J3/005 Primary

  Electricity · mapped topic

• H05B47/13

  by using passive infrared detectors · CPC title

• Y02B20/40

  Control techniques providing energy savings, e.g. smart controller or presence detection · CPC title