Method and apparatus for using an infrared reflectivity sensor in a security system

• US 20080030328A1
• Filed: 08/03/2006
• Published: 02/07/2008
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: Tyco Safety Products Canada Limited (Johnson Controls International plc)
• Inventors: Sharma, Raman Kumar
• Granted Patent: US 7,986,232 B2
• Time in Patent Office: Days
• US Class Current: 340/552
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G08B 25/14 Central alarm receiver or annunciator arrangements

Abstract

The IR sensor is configured to be mounted proximate to a door to be monitored. The IR sensor has an IR transmitter and an IR receiver. The IR transmitter has an active period and an idle period. The IR transmitter transmits control data packets which are provided by the processor during the active period. The IR receiver has an active period for detecting IR data and reflected data packets. Each of the reflected data packets has a packet IR reflectivity. The memory stores a door IR reflectivity associated with a door surface of the door, and the processor compares the packet IR reflectivity to the door IR reflectivity to determine at least a door position of the door.

Claims

1. A security system, comprising:

an infrared (IR) sensor configured to be mounted proximate to a door to be monitored, the IR sensor having an IR transmitter and an IR receiver, the IR transmitter having an active period and an idle period, the IR transmitter transmitting control data packets during the active period, the IR receiver having an active period for detecting reflected data packets and IR data, each of the reflected data packets having a packet IR reflectivity;

a processor providing the control data packets to be transmitted by the IR transmitter; and

a memory storing a door IR reflectivity associated with a door surface of the door, the processor comparing the packet IR reflectivity to the door IR reflectivity to determine at least a door position of the door.

2. The system of claim 1, further comprising a filter for filtering reflected data packets, the IR receiver receiving the IR data representative of background noise during the idle period of the IR transmitter, the filter filtering the reflected data packets based on the IR data.

3. The system of claim 1, the IR transmitter transmitting a first control data packet, the processor identifying a door open position associated with the door when a first reflected data packet corresponding to the first control data packet is not received by the IR receiver.

4. The system of claim 1, the processor identifying a door closed position associated with the door when the door IR reflectivity data and the packet IR reflectivity are one of substantially the same and within a predetermined IR range.

5. The system of claim 1, the processor initiating a trouble indication when the door IR reflectivity and the packet IR reflectivity are different with respect to each other.

6. The system of claim 1, further comprising a network interconnecting the IR sensor, the processor and the memory with a system control panel, the processor transmitting a trouble indication over the network to the system control panel when the door IR reflectivity and the packet IR reflectivity are different with respect to each other.

7. The system of claim 1, further comprising a control panel mounted proximate to the IR sensor and the processor, the control panel further comprising at least one of a backlight, an interface device and interface circuitry, the processor activating at least one of the backlight, the interface device and the interface circuitry when the door IR reflectivity and the packet IR reflectivity are different with respect to each other.

8. The system of claim 1, further comprising a control panel located proximate to the door, wherein the IR sensor is one of mounted within a door frame proximate to the door, mounted on a wall proximate to the door, and mounted on the control panel.

9. The system of claim 1, further comprising an IR reflector mounted on the door, the IR transmitter being positioned to reflect the control data packet off the IR reflector when the door is in a predetermined position, the door IR reflectivity further comprising IR reflectivity based on the IR reflector.

10. A method for using an IR sensor to detect a door position in a security system, comprising:

transmitting a control data packet with an infrared (IR) transmitter of an IR sensor to detect a surface associated with a door;

receiving a reflected data packet with an IR receiver of the IR sensor, the reflected data packet having a packet IR reflectivity;

comparing the packet IR reflectivity to a door IR reflectivity, the door IR reflectivity being based on the surface associated with the door; and

determining a status of the door based on the comparison of the packet and door IR reflectivity.

11. The method of claim 10, further comprising:

receiving IR data with the IR receiver to determine a level of background noise; and

filtering the reflected data packet based on the IR data.

12. The method of claim 10, further comprising identifying a door open position when a reflected data packet is not received by the IR receiver.

13. The method of claim 10, further comprising identifying a door closed position when the packet IR reflectivity and the door IR reflectivity are at least one of substantially the same and within a predetermined IR range.

14. The method of claim 10, further comprising initiating a trouble indication when the door IR reflectivity and the packet IR reflectivity are different with respect to each other.

15. The method of claim 10, further comprising:

positioning the door in a closed position;

transmitting an initial control data packet with the IR transmitter; and

receiving a reflected initial control packet with the IR receiver, the door IR reflectivity being based on the reflected initial control packet.

16. The method of claim 10, further comprising filtering the reflected data packet to remove background IR data.

17. A security system, comprising:

a security control panel;

an infrared (IR) sensor mounted proximate to a door to be monitored and having an IR transmitter and an IR receiver, the IR sensor located remote from the security control panel and connected to the security control panel by a network, the IR transmitter having an active period and an idle period, the IR transmitter transmitting control data packets during the active period, the IR receiver detecting reflected data packets and IR data, the reflected data packets reflecting off a surface and having a packet IR reflectivity;

a processor providing the control data packets to be transmitted by the IR transmitter, the processor comparing a door IR reflectivity associated with a door surface to the packet IR reflectivity to determine a door position of the door; and

means for transmitting a status signal from the IR sensor to the security control panel based on the comparison of the door IR reflectivity and the packet IR reflectivity.

18. The security system of claim 17, wherein the processor initiates a trouble signal when the packet IR reflectivity and the door IR reflectivity are different with respect to each other, the trouble signal being transmitted as the status signal to the security control panel.

19. The security system of claim 17, wherein the door surface further comprises an edge of the door, a front face of the door, a back face of the door and a reflector mounted to the door.

20. The security system of claim 17, further comprising means for filtering the reflected data packet to remove background IR data.