Large gap door/window, high security, intrusion detectors using magnetometers

摘要

A door, or window detector incorporates a magnet and a magnetometer. Dual loop processing can be provided for real-time signals from the magnetometer, as the magnet moves relative to it, to determine when at least one of small gap or large gap indicating alarms should be issued. Security can be substantially increased by randomizing the orientation of the magnet.

主权项

1. A detector comprising:
a proximity sensor; and circuitry having first and second distance sensing thresholds, wherein the circuitry compares a proximity signal, from the sensor, to the first distance sensing threshold, wherein, when the proximity signal fails to exceed the first distance sensing threshold, the circuitry sends a signal indicative of an alarm relative to both the first and second distance sensing thresholds to a displaced control unit, wherein, when the proximity signal exceeds the first distance sensing threshold, the circuitry compares the proximity signal to the second distance sensing threshold, wherein, when the proximity signal fails to exceed the second distance sensing threshold, the circuitry sends a signal indicative of an alarm relative to the second distance sensing threshold and a signal indicative of a normal state relative to the first distance sensing threshold to the displaced control unit, and wherein, when the proximity signal exceeds the second distance sensing threshold, the circuitry sends a signal indicative of a normal state relative to the first and second distance sensing thresholds to the displaced control unit.