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Infrared detector for detecting motion and fire and an alarm system including the same

  • US 5,486,810 A
  • Filed: 12/13/1994
  • Issued: 01/23/1996
  • Est. Priority Date: 02/04/1993
  • Status: Expired due to Term
First Claim
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1. A detector which detects motion and changes in ambient temperature comprising:

  • a) a first passive infrared sensor and a second passive sensor, said first and second passive sensors coupled to each other in phase opposition and providing a first output;

    b) first circuit means coupled to said first output for providing an intrusion alarm when infrared radiation detected by said first passive infrared detector differs from said second passive infrared detector according to first criteria; and

    c) second circuit means coupled to said first passive infrared sensor at a common connection between said first and second passive infrared sensors for providing an ambient temperature change alarm when said first passive infrared sensor detects a change in infrared radiation that exceeds a predetermined amount over a predetermined time.

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