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Wireless multi-head smoke detector system

  • US 4,160,246 A
  • Filed: 10/03/1977
  • Issued: 07/03/1979
  • Est. Priority Date: 10/03/1977
  • Status: Expired due to Term
First Claim
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1. A detector/transmitter unit for a wireless smoke detector system comprising at least one detector/transmitter unit and a receiver/annunciator unit for producing alarm signals in response to actuating signals transmitted by radio frequency waves from said at least one detector/transmitter unit, said detector/transmitter unit comprising:

  • pulse means for repetitively generating a clock signal;

    an infrared source for repetitively generating a beam of infrared radiation responsive to said clock signal and substantially coincident in time with said clock signal;

    a photodetector having a collection axis angularly intersecting said beam for detecting infrared radiation reflected from smoke particles encountered by said beam and for developing an infrared detection signal whenever smoke particles are detected;

    low battery voltage detecting means for monitoring the voltage across a power source for the detector/transmitter unit and for developing a low battery signal whenever said voltage falls below a predetermined level; and

    transmitter means (1) for generating a first actuating signal for said receiver/annunciator unit in response to both said clock signal and said low battery signal, and (2) for generating a second actuating signal for said receiver/annunciator in response to both said clock signal and said detection signal.

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