Multi-mode Passive Infrared Occupancy Sensor System For Energy Saving Application

• US 20160003493A1
• Filed: 03/25/2015
• Published: 01/07/2016
• Est. Priority Date: 07/03/2014
• Status: Active Grant

• Current Assignee: Fred Katz Consulting, Inc.
• Original Assignee: Fred Katz Consulting, Inc.
• Inventors: Katz, Fred
• Granted Patent: US 9,739,498 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 2120/10 Occupancy
• CPC Class Codes: F24F 2120/12 Position of occupants

Abstract

A passive infrared (PIR) motion sensor system includes a non-contact thermopile detector for capturing infrared energy from a focused upon area in a room or zone deemed most likely to be occupied and generating a thermopile temperature signal therefrom, a pyroelectric detector for viewing through multiple passive lens elements (lenslets) that form PIR beams from a large portion of the room or zone and generating a pyroelectric signal therefrom, an ambient temperature sensor for sensing an ambient temperature in the room or zone and generating an ambient temperature signal detection threshold that is utilized in PIR detection therefrom and a microcomputer configured to process the thermopile temperature signal, the pyroelectric signal and the ambient temperature signal and determine whether the room or zone is occupied or unoccupied. An electrical current supply or occupied signal is transmitted to the room or zone is maintained when the microcomputer determines that the room or zone is still occupied and is interrupted when the microcomputer determines that the room or zone is unoccupied.

Claims

1. A passive infrared (PIR) motion sensor system, comprising:

a pyroelectric detector for receiving multiple passive PIR beams from a Fresnel lens aimed at a large portion of the room or zone and upon sensing a moving human generating a pyroelectric signal;

which is fed to a

a microcomputer configured to measure and process the pyroelectric signal and the ambient temperature signal and determine whether the room or zone is occupied;

a non-contact thermopile detector for performing a non-contact temperature measurement by capturing infrared energy from a selected focused upon area in a room or zone and generating a thermopile temperature signal therefrom;

that is fed to a microcomputer for determination if there is a stationary human present when the system enters an occupied state;

and an ambient temperature sensor for measuring the ambient temperature in the room or zone and generating an ambient temperature internal data;

wherein an electrical current supply or control signal is output to the room or zone is maintained or transmitted when the microcomputer determines that the room or zone is occupied and is interrupted or reduced when the microcomputer determines that the room or zone is unoccupied.

2. The passive infrared (PIR) motion sensor system of claim 1, wherein the room or zone is determined to be occupied based on detected movement in the room or zone that is reflected in the pyroelectric signal alone and continues to detect and maintain an occupied status in the room or zone.

3. The non-contact temperature measurement thermopile sensor sub-system of claim 1, wherein the room or zone is determined continue to be occupied based on a difference between the ambient temperature data and the thermopile temperature data generated by a thermopile detector focused on a particular directed zone.

4. The passive infrared (PIR) motion sensor system of claim 1, wherein no movement is detected by the pyroelectric detector but wherein the room or zone is determined to continue to be occupied based on a difference between the ambient temperature signal and the thermopile temperature signal which is focused on a zone within a room or an area.

5. The passive infrared (PIR) motion sensor system of claim 1, further comprising a transmitter, wherein the microcomputer sends a status transition signal to the transmitter upon determining that the room or monitored zone in in either the occupied or unoccupied state and additionally transmit various status signals at periodic or aperiodic intervals.

6. The passive infrared (FIR) motion sensor system of claim 5, wherein the transmitter transmits an electrical current supply control signal that is used by a controller to control the electrical current supply to the room or zone.

7. The passive infrared non-contact thermopile detector system of claim 1, wherein the thermopile detector is directed at the area focused upon to measure a temperature of a surface of skin or clothes of a person in the monitored zone, if present and an inanimate object in the focused upon area if there is no person present.

8. The passive infrared (PIR) motion sensor system of claim 1, further comprising a battery or an adaptor for connection to a conventional alternating current (AC) supply of electrical current.

9. The passive infrared (PIR) motion sensor system of claim 1, further comprising a housing including a single or dual lens window portion through which the non-contact thermopile detector and the pyroelectric detector capture infrared light energy.

10. The thermopile detection system of claim 1, wherein the microcomputer generates a difference factor for use in determining presence based on the difference between the temperatures of focused upon monitored area and the detected ambient air temperature.

11. The invention of claim 1, wherein microcomputer incorporates a temperature calibration factor for detecting the actual room temperature and using said temperature for adjusting the sensitivity of the motion detector and for correction of thermopile detector measured values.

12. The passive infrared (PIR) motion sensor system of claim 10, wherein the calibration factor and hence the derivative calculated threshold value is an average of ambient temperature signals captured by microcomputer or a thermistor temperature sensor over a fixed time period.

13. The passive infrared (PIR) motion sensor system of claim 10, wherein the temperature corrected by a calibration factor which is processed to contribute to the generation of the PIR detection threshold voltage is generated during a time when there has not been any movement detected by the thermopile detector, which is indicative of an unoccupied state.

14. The passive infrared (PIR) motion sensor system of claim 1, wherein upon detecting an occupancy of the room or zone, the controller switches to provide the supply in the ‘

occupied’

state and switch to interrupt the supply when the thermopile and the PIR motion sensor both do not detect any motion after a fixed time cause the product to enter the ‘

unoccupied’

state.

15. A method of using a passive infrared (PIR) motion sensor system to control an electrical current supply to the room or zone based on a determination that the room or zone is occupied, the system comprising a non-contact thermopile detector, a pyroelectric detector, an ambient temperature sensor and a microcomputer, the method comprising the steps of:

if a person is detected to move in the zone or room by the pyroelectric detector, the pyroelectric detector sends an interrupt signal to the microcomputer which processes the signal and if it is deemed a valid signal generates and provides an occupied signal to a controller to enable or maintain the electrical current supply to the room or zone;

if a person is not detected to move in the zone or room by the pyroelectric detector, the microcomputer periodically compares a non-contact temperature signal generated by the thermopile detector with an ambient temperature signal generated by the ambient temperature sensor; and

upon detecting a temperature difference, the microcomputer generates and continuously provides an occupied signal to a controller to enable or maintain the electrical current supply or ‘

occupied’

control signal to the room or zone; and

upon the thermopile detector detecting substantially no temperature difference, and the PIR detector not detecting any signal indicative of motion;

the microcomputer generates and provides an unoccupied signal to a controller to reduce or extinguish the electrical current supply to the room or zone'"'"'s lamps, HVAC or other occupancy dependent room features.

16. The method of claim 15, further including generating and relying upon a timeout before said unoccupied signal is generated.