C & K Systems, Inc.

Frederick W Eggers

Lawrence R Tracy

David Houston

Paul M Hoseit

Gordon S Whiting

Jeffrey Bamford

Walter B Wallace

Dale Dorando

A dual sensing intrusion detection system has a microwave channel and a PIR channel. The signal from the microwave channel is amplified by an amplifier having a substantially constant gain, and is digitized and converted into a first digital signal. The signal from the PIR detector is amplified by amplifier having a substantial constant gain and is digitized and converted into a second digital signal. The first and second digital signals are compared to a microwave threshold signal and a PIR threshold signal respectively to generate an alarm signal. The system has a thermistor to detect the ambient temperature. The PIR threshold signal can be adjusted based upon changes in static conditions from the output of the thermistor. In addition, the microwave threshold signal can be changed statically based upon long term trend of the first digitized signal. Finally, the PIR threshold signal and the microwave threshold signal can be changed based upon detection from the other respective channel due to dynamic changes in the environment.

Intrusion detection system having self-adjusting threshold

An intrusion detector test circuit automatically disables a detected-event indicator from receiving sensing signals. A sensor generates a sensing signal in response to a detection of an installer testing the intrusion detector. An indictor means receives the sensing signals and generates detected-event indications in response to the sensing signals. A switch interposed between the sensor and the indicator receives the sensing signals. In a first state, the switch supplies the sensing signals to the indicator; in a second state, the switch means does not supply the sensing signals to the indicator. A first state setter sets the switch to the first state, and a second state setter automatically sets the switch to the second state after a lapse of a predetermined time period.

Intrusion detector test circuit which automatically disables a

A dual technology intrusion detection device has a microwave detection sub-system, employing a bent mono-pole as an antenna to generate a symmetrical conically shaped volume of protection. The intrusion detection system also has a passive infrared intrusion detection sub-system, employing a hemispherically shaped fresnel lens having a plurality of lens segments, to detect infrared radiation from a plurality of spaced apart fields of view in a right symmetrical cone. The volume of protection for the infrared intrusion detector and microwave detector substantially coincide. In addition, the microwave detection sub-system employs a single bipolar transistor and a variable trim capacitor to generate the microwave energy and also uses the single bipolar transistor in an autodyne mode to mix the received microwave radiation.

Location independent intrusion detection system

Infra-red intruder detector

Growing community of inventors

Dixon, CA, United States of America

Frederick W Eggers