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Intruder detection system with programmable countdown timer for self-supervision

  • US 5,083,106 A
  • Filed: 02/11/1991
  • Issued: 01/21/1992
  • Est. Priority Date: 02/11/1991
  • Status: Expired due to Term
First Claim
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1. An intruder detection system comprising:

  • (a) an intrusion sensor for detecting intrusion in a region of interest, said sensor being adapted to produce a sensor output signal upon detecting intrusion;

    (b) intrusion alarm means operatively coupled to said sensor and responsive to said sensor output signal for producing an intrusion alarm;

    (c) a programmable countdown timer for counting-down a preselected time interval and for producing a timer output signal at the end of said preselected time interval, said programmable countdown timer being responsive to said sensor output signal to reset the time remaining in the countdown when said sensor output signal is produced to the maximum length of said preselected time interval; and

    (d) supervisory alarm means, responsive to said timer output signal, for producing a supervisory alarm in the event said sensor output signal is not produced within said preselected time interval.

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