Invisible alarm help!

Discussion in 'The Projects Forum' started by Chris15, Jun 16, 2009.

  1. Chris15

    Thread Starter Active Member

    Apr 15, 2009
    252
    0
    Hi
    if you have put your hands under an electronic hand dryer you will know the circuit im talking about, a infrared LED when you interupt the signal it triggers something (in this case the dryer) how could i make a simple circuit, and how does it work?

    Thanks guys
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Look up Passive Infrared Receiver (PIR).
     
  3. awwende

    Active Member

    Feb 17, 2009
    39
    0
    I don't know if you have any programing experience, but you could use a micro controller like the Arduino or Basic Stamp and use a ultrasonic range finder so if an object is say 2cm or less away it triggers whatever device you plan on using
     
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