Method and apparatus for adjusting an ambient light threshold

• US 10,159,137 B2
• Filed: 06/08/2015
• Issued: 12/18/2018
• Est. Priority Date: 06/10/2011
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Bedell, Ryan S., Steiner, James P.
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Sathiraju, Srinivas
• Application Number:
  US14/733,867
• Publication Number:
  US 20150271897A1
• Time in Patent Office: 1,289 Days
• Field of Search: None
• CPC Class Codes: H05B 47/105 in response to determined parameters
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/13 by using passive infrared detectors
• CPC Class Codes: H05B 47/16 by timing means
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A load control device adapted to be coupled between an AC power source and an electrical load for controlling the power delivered to the load includes a controller, an actuator for turning the electrical load on and off, an occupancy detection circuit, and an ambient light detector. The load control device automatically turns on the electrical load in response to the presence of an occupant only if the detected ambient light is below a predetermined ambient light level threshold. After first detecting the presence of an occupant, the load control device monitors actuations of the actuator to determine whether a user has changed the state of the load. The load control device automatically adjusts the predetermined ambient light level threshold in response to the user actuations that change the state of the load.

Claims

1. An apparatus for controlling power delivered from a power source to an electrical load in a space, the apparatus comprising:

an actuator;

an occupancy detection circuit for detecting the presence of an occupant in the space;

an ambient light detector for measuring an ambient light level in the space; and

a controller configured to;

control the electrical load in response to actuations of the actuator;

detect the presence of an occupant in the space based on an output received from the occupancy detection circuit;

compare a measured ambient light level received from the ambient light detector to an ambient light level threshold;

determine whether to control the electrical load based on comparing the measured ambient light level to the ambient light level threshold; and

responsive at least in part to detecting the presence of an occupant;

detect whether there is an actuation of the actuator; and

adjust the ambient light level threshold when an actuation of the actuator is detected.

2. The apparatus of claim 1, wherein the controller is configured to calculate a difference between the measured ambient light level and a first value of the ambient light level threshold, and use the calculated difference to adjust the ambient light level threshold from the first value to a second value.

3. The apparatus of claim 2, wherein the controller is configured to multiply the calculated difference by a scaling factor, and adjust a value of the measured ambient light level by the product of the calculated difference and the scaling factor to generate an adjusted value of the ambient light level threshold, the controller further configured to use the adjusted value of the ambient light level threshold to adjust the ambient light level threshold from the first value to the second value.

4. The apparatus of claim 3, wherein the adjusted value of the ambient light level threshold is the second value of the ambient light level threshold.

5. The apparatus of claim 3, wherein the controller is configured to digitally filter the adjusted value of the ambient light level threshold to generate the second value of the ambient light level threshold.

6. The apparatus of claim 1, wherein, if the measured ambient light level is less than the ambient light level threshold, the controller is configured to turn the electrical load on in response to detecting the presence of an occupant.

7. The apparatus of claim 6, wherein:

to detect whether there is an actuation of the actuator comprises to receive an actuation of the actuator to turn the electrical load off after turning the electrical load on in response to detecting the presence of an occupant; and

to adjust the ambient light level threshold comprises to decrease the ambient light level threshold in response to receiving the actuation of the actuator to turn the electrical load off after turning the electrical load on in response to detecting the presence of an occupant.

8. The apparatus of claim 1, wherein, if the measured ambient light level is greater than the ambient light level threshold, the controller is configured to maintain the electrical load off in response to detecting the presence of an occupant.

9. The apparatus of claim 8, wherein:

to detect whether there is an actuation of the actuator comprises to receive an actuation of the actuator to turn the electrical load on after maintaining the electrical load off in response to detecting the presence of an occupant; and

to adjust the ambient light level threshold comprises to increase the ambient light level threshold in response to receiving an actuation of the actuator to turn the electrical load on after maintaining the electrical load off in response to detecting the presence of an occupant.

10. The apparatus of claim 1, further comprising:

a controllably conductive device adapted to be coupled between the power source and the electrical load for controlling the power delivered to the electrical load,

wherein the controller is operatively coupled to the controllably conductive device and is configured to render the controllably conductive device conductive and non-conductive to turn the electrical load on and off, respectively.

11. The apparatus of claim 1, wherein the controller is further configured to detect a second occupancy condition, and compare a second measured ambient light level to the adjusted ambient light level threshold.

12. The apparatus of claim 1, wherein the controller is further configured to adjust the ambient light level threshold when an actuation of the actuator is detected within a predetermined time window after detecting the presence of an occupant.

13. A method for controlling power delivered from a power source to an electrical load, the method comprising:

detecting an occupancy condition;

comparing a measured ambient light level to a first value of an ambient light level threshold;

determining whether to control the electrical load based on detecting the occupancy condition and based on comparing the measured ambient light level to the first value of the ambient light level threshold; and

and

responsive at least in part to detecting the occupancy condition;

detecting whether there is an actuation to adjust the power delivered to the electrical load; and

adjusting the ambient light level threshold to a second value when an actuation to adjust the power delivered to the electrical load is detected.

14. The method of claim 13, wherein adjusting the ambient light level threshold further comprises:

calculating a difference between the measured ambient light level and the first value of the ambient light level threshold; and

using the calculated difference to adjust the ambient light level threshold from the first value to the second value.

15. The method of claim 14, wherein adjusting the ambient light level threshold further comprises:

multiplying the calculated difference by a scaling factor; and

adjusting a value of the measured ambient light level by the product of the calculated difference and the scaling factor to generate an adjusted value of the ambient light level threshold,

wherein the adjusted value of the ambient light level threshold is used to adjust the ambient light level threshold from the first value to the second value.

16. The method of claim 15, wherein the adjusted value of the ambient light level threshold is the second value of the ambient light level threshold.

17. The method of claim 15, wherein adjusting the ambient light level threshold further comprises digitally filtering the adjusted value of the ambient light level threshold to generate the second value of the ambient light level threshold.

18. The method of claim 13, further comprising:

if the measured ambient light level is greater than the first value of the ambient light level threshold, maintaining the electrical load off in response to detecting the occupancy condition; and

wherein detecting whether there is an actuation to adjust the power delivered to the electrical load comprises receiving an actuation to turn the electrical load on after maintaining the electrical load off in response to detecting the occupancy condition.

19. The method of claim 18, wherein adjusting the ambient light level threshold further comprises increasing the ambient light level threshold from the first value to the second value in response to receiving an actuation to turn the electrical load on after maintaining the electrical load off in response to detecting the occupancy condition.

20. The method of claim 13, further comprising:

if the measured ambient light level is less than the first value of the ambient light level threshold, turning the electrical load on in response to detecting the occupancy condition; and

wherein detecting whether there is an actuation to adjust the power delivered to the electrical load comprises receiving an actuation to turn the electrical load off after turning the electrical load on in response to detecting the occupancy condition.

21. The method of claim 20, wherein adjusting the ambient light level threshold further comprises decreasing the ambient light level threshold from the first value to the second value in response to receiving an actuation to turn the electrical load off after turning the electrical load on in response to detecting the occupancy condition.

22. The method of claim 13, further comprising:

detecting a second occupancy condition; and

comparing a second measured ambient light level to the adjusted ambient light level threshold.

23. The method of claim 13, wherein adjusting the ambient light level threshold further comprises adjusting the ambient light level threshold to the second value when an actuation to adjust the power delivered to the electrical load is detected within a predetermined time window after detecting the occupancy condition.