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Smoke Detector

Discussion in 'General Electronics Discussion' started by grkmr, Mar 16, 2011.

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  1. grkmr

    grkmr

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    Jan 31, 2011
    Hi all,

    I am responsible for designing a smoke detector that detects smoke with the help of a laser. It must detect and seperate smoke from the other solid objects. I can (must) use PIC programming. I have no clue about how to start creating the project. Anyone wants to help me?
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    what other solid objects ? over what distance ?

    Most smoke detectors use a radioactive source the emission of alpha particles are detected over a small distance ~ 1cm. The very fine smoke particles coming betreen detector and emitter absorb the emitted particles and decreases the particle count picked up by the detector.

    You may be able to do something with a laser in that photons of the laser light will be scattered and hence the intensity of the beam arriving at the detector will be lower than normal (when there is no smoke). But detecting difference in size/ type of object is going to be very difficult.

    Dave
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    I remember a smoke detector from many years ago that sent a beam of light across a room. It presumably detected changes in intensity. To preclude solid objects, there were 4 (if I recall correctly) thin cables around the beam to prevent you from accidentally occluding it.
     
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