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5 Zone Alarm System

Discussion in 'Electronic Projects' started by ElectroMaster, Jul 24, 2002.

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  1. oldtimer

    oldtimer New Member

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    have you tried holding a magnet near a reed switch to keep it closed while you open the door or window? I haven't but it would be interesting to find out.
     
  2. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You need to know exactly where the reed is hidden, and also which way round the existing magnet is - or you've got a 50% change of setting the alarm off when you apply your magnet!.
     
  3. oldtimer

    oldtimer New Member

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    Yes I know that Nigel but it is fairly easy to find the switch since it has its own magnet and the polarity can be found without operating the reed, I prefer to use plate to plate contacts not because of reed problem,I just thought of that, but because they're cheap and reliable. I was born in Sheffield and hiked around Derbyshire in my youth,durint war tha nose.
     
  4. dave

    Dave New Member

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  5. usmankhan

    usmankhan New Member

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    hello,
    Its very nice
     
  6. densimitre

    densimitre New Member

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    Hi
    I need detect a bell fault in a PIC alarm based project....

    the circuit is a common npn transistor with collector pull to 12 volts and a diode to protect tehm from inverse emf coming from relay or bell....

    thank you
     
  7. neilz90

    neilz90 New Member

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    could anyone tell me how to compensate for only 3 zones. I've got it drawn but I haven't filed in any of the values.
     
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