Wireless security system

• US 6,310,549 B1
• Filed: 08/29/2000
• Issued: 10/30/2001
• Est. Priority Date: 08/29/2000
• Status: Expired due to Fees

• Current Assignee: Preferred Technology Systems, LLC (Assa Abloy AB)
• Original Assignee: Digitech International Incorporated (The Chamberlain Group LLC)
• Inventors: Crane, Richard, Crane, Jerry, Loftin, Jon
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US09/651,537
• Time in Patent Office: 427 Days
• Field of Search: 340/545.1, 340/545.6, 340/545.9, 340/547, 340/551, 340/539, 340/693.9, 340/568.1, 340/571, 340/689, 324/207.13, 324/207.21, 324/207.22, 200/61.62, 200/61.45 R, 200/61.52
• US Class Current: 340/547
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind

Abstract

The present invention is a wireless security system. Each alarm sensor contains three magnetoresistive sensors and that are capable of detecting the three-dimensional vector of a magnetic field. Preferably, the sensors detect the orientation of the door or window based upon the earth'"'"'s magnetic pole. The three-dimensional vector output of the magnetoresistive sensors is received by a microprocessor on-board the alarm sensor. The microprocessor continuously compares the magnetoresistive sensors output with the maximum allowable position of the door or window. If the magnetoresistive sensors output exceeds the maximum allowable position, the microprocessor will signal an alarm, which is transmitted to the network controller via a transmitter on-board the alarm sensor. If an intruder attempts to disable or override a sensor, the alarm sensor will transmit a tamper signal to the network controller.

Claims

1. An alarm sensor comprising:

a housing;

detecting means carried by said housing for detecting movement of said housing, wherein said detecting means comprises means for detecting changes in the position of said housing relative to the three-dimensional vector of a magnetic field; and

alarm means in electrical connection with said detecting means and carried by said housing for signaling when said detecting means detects movement of said housing.

2. The alarm sensor as recited in claim 1, wherein said housing is capable of being mounted to the exterior portion of a door.

3. The alarm sensor as recited in claim 2, further comprising tamper means for detecting the presence of an external magnetic field in proximity to said housing.

4. The alarm sensor as recited in claim 1, wherein said detecting means comprises means for detecting changes in position of said housing relative to the three-dimensional vector of the earth'"'"'s magnetic field.

5. The alarm sensor as recited in claim 1, wherein said detecting means comprises at least two magnetoresistive sensors.

6. The alarm sensor as recited in claim 1, wherein said housing is mounted to a surface, and wherein said alarm sensor further comprises tamper means for detecting the detachment of said housing from the surface.

7. The alarm sensor as recited in claim 1, wherein said alarm means further comprises means for signaling using RF communications.

8. The alarm sensor as recited in claim 1, wherein said housing is capable of being mounted to a window.

9. An alarm sensor comprising:

a housing;

detecting means carried by said housing for detecting changes in the position of said housing relative to the three-dimensional vector of the earth'"'"'s magnetic field; and

alarm means in electrical connection with said detecting means and carried by said housing for signaling when said detecting means detects movement of said housing.

10. The alarm sensor as recited in claim 9, wherein said detecting means comprises at least two magnetoresistive sensors.

11. The alarm sensor as recited in claim 10, further comprising tamper means for detecting the presence of an external magnetic field in proximity to said housing.

12. The alarm sensor as recited in claim 10, wherein said housing is mounted to a surface, and wherein said alarm sensor further comprises tamper means for detecting the detachment of said housing from the surface.

13. The alarm sensor as recited in claim 10, wherein alarm means further comprises means for signaling using RF communications.

14. The alarm sensor as recited in claim 10, wherein said housing is capable of being mounted to the exterior portion of a door.

15. The alarm sensor as recited in claim 10, wherein said housing is capable of being mounted to a window.

16. A security system comprising:

at least one alarm sensor having

a housing,

at least two magnetoresistive sensors carried by said housing, said at least two magnetoresistive sensors capable of detecting the three-dimensional vector of a magnetic field;

comparator means carried by said housing and in electrical connection with said at least two magnetoresistive sensors, said comparator means capable of determining changes in the detections of said at least two magnetoresistive sensors;

alarm means in electrical connection with said at least two magnetoresistive sensors and carried by said housing for signaling when said comparator means determines changes in the detections of said at least two magnetoresistive sensors; and

a network controller capable of receiving signals from each said alarm means of said at least one alarm sensor.

17. The security system as recited in claim 16, further comprising tamper means for detecting the presence of an external magnetic field in proximity to said housing.

18. The security system as recited in claim 16, further comprising tamper means for detecting the detachment of said housing from a surface in which said housing is mounted.

19. The security system as recited in claim 16, wherein said housing of said at least one sensor is capable of being mounted to the exterior portion of a door.