Intruder detection system
OwnerJohn A. Rossininventor
Life of this patent
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Abstract
The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.
Claims11
An improved detection system for optically monitoring an area an producing an alarm signal only in response to motion of an intruder across the monitoring area, including:
- (a) A sensor optically responsive to infrared radiation of an intruder, the sensor having at least a pair of discrete sensor areas each producing an electrical output in response to infrared radiation;
- (b) Means optically directing infrared radiation from only the monitored area onto the discrete sensor areas of the sensor, radiation from only a portion of the monitored area being directed onto each sensor area, whereby movement of an intruder across the monitored area causes one then the other of the sensor areas of the pair to produce an electrical output;
- (c) Electronic means accepting and analyzing the electrical outputs of the sensor areas and producing said alarm signal in response to the occurence of an electrical output of one sensor area then of the other sensor area of a pair within a predetermined period of time, the electronic means including
- (i) at least two separate electronic channels responding respectively to the electrical output of the discrete sensor areas of the pair, the channels each being responsive to the presence of the electrical output of a discrete sensor area to produce an output in response to said electrical output above a given threshold level,
- (ii) means automatically adjusting the sensitivity of at least one channel in response to the output of the other channel to cause said one channel to produce an output in response to an input above a threshold level lower than said given threshold level, and
- (iii) means analyzing the outputs of the electronic channels and producing an alarm signal in response to the occurrence of said channel outputs within a predetermined period of time.
Dependencies are inferred from the claim text.