Presence detector and its application

• US 20010015409A1
• Filed: 12/13/2000
• Published: 08/23/2001
• Est. Priority Date: 12/17/1999
• Status: Active Grant

• Current Assignee: Siemens Technologies AG Cerberus Division
• Original Assignee: Siemens Building Technologies Limited (Siemens AG)
• Inventors: Rechsteiner, Martin, Mahler, Hansjurg, Abrach, Rolf
• Granted Patent: US 6,486,778 B2
• Time in Patent Office: Days
• US Class Current: 250/342
• CPC Class Codes: G08B 13/19697 Arrangements wherein non-video detectors generate an alarm themselves

Abstract

The presence detector has a passive infrared sensor for detecting the presence of persons in a room, an image sensor operating in the visible spectral range and an electronic evaluator for the evaluation of signals from these sensors. The signal from the passive infrared sensor is used to actuate the image sensor and, if necessary, to switch on the room lighting. Once activated, the image sensor is used to detect both movement and occupancy of a space being monitored. Application of the presence detector for the “on-demand” activation and/or control of conditioning facilities of a room, wherein the signals of both sensors are used for the control of the conditioning facility.

Claims

1. A presence detector comprising:

a passive infrared sensor;

an image sensor operating in the visible spectral range; and

an electronic evaluator operationally coupled with said passive infrared sensor and said image sensor, said image sensor being activated in response to a signal from said passive infrared sensor, said electronic evaluator having at least one output for operating a conditioning facility.

2. A presence detector of

claim 1

, wherein said conditioning facility includes lights in a room and said lights are turned in response to a signal from said passive infrared sensor indicating that a person has entered.

3. A presence detector of

claim 2

, wherein the image sensor is provided to detect the presence of persons in the room.

4. A presence detector of

claim 3

, wherein the image sensor is a complementary metal-oxide semiconductor image sensor.

5. A presence detector of

claim 4

, wherein said image sensor is an active pixel sensor.

6. A presence detector of

claim 1

, wherein said image sensor provides a signal to the electronic evaluator having a measure of ambient brightness.

7. A presence detector of

claim 1

, wherein said image sensor further comprises a brightness sensor operationally coupled with said electronic evaluator.

8. A presence detector of

claim 7

, wherein said brightness sensor further comprises a photo-diode.

9. A presence detector of

claim 6

, wherein a signal from said image sensor is used to switch off the room lighting when the ambient brightness is sufficient to operate the image sensor.

10. A presence detector of

claim 1

, wherein said image sensor'"'"'s visual range is subdivided into a plurality of partial areas, each of said partial areas being imaged on the same area of the image sensor.

11. A presence detector of

claim 1

, wherein said electronic evaluator further evaluates signals from said image sensor to determine any movements in a visual range of said image sensor.

12. A presence detector of

claim 10

, wherein said electronic evaluator further evaluates signals from said image sensor to determine any movements in said visual range of said image sensor.

13. A presence detector of

claim 10

, further comprising an optical system for subdividing the visual range and presenting said plurality of partial areas onto said image sensor.

14. A presence detector of

claim 2

, wherein said conditioning facility further comprises a climate control system and wherein said electronic evaluator provides control signals on said output to control said climate control system.

15. A presence detector of

claim 14

, wherein said electronic evaluator determines the occupancy of the room in response to the image sensor and wherein said control signals are related to said occupancy.

16. A presence detector of

claim 14

, wherein said control signals are related to both the PIR and image sensor.

17. A presence detector of

claim 7

, wherein said electronic evaluator determines an ambient brightness based on a signal from said brightness sensor, and wherein said electronic evaluator further controls the lighting in the operational range of said image sensor based on the determined ambient brightness.

18. A presence detector of

claim 17

, wherein a signal from said image sensor is further used to switch off the lighting.