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Homework Help: Automatic doors

  1. Apr 26, 2006 #1
    how does a automatic door works?
    anythings about the photodiode? and lazer???

    plx help~~~~
  2. jcsd
  3. Apr 26, 2006 #2


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    Staff: Mentor

    You must have some idea about how they work, right? Why don't you tell us how you think they work, and we'll help you from there....
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