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Homework Help: Need help in a project

  1. Oct 26, 2011 #1
    Hi, I am making up a Velocity Counter using a photo diode. I have planned it to be in the following way:

    I will be having two ends, on both of those ends I will be having photo diodes on one side and laser lights falling on the diodes from exactly opposite sides. Now I will make a toy car move, once the toy car intercepts the first light beam, I want my counter to start the time immediately and as soon as it intercepts the other beam, I want it to stop.

    Can anyone guide me please.

  2. jcsd
  3. Oct 26, 2011 #2


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    Staff: Mentor

    We don't do your projects for you here on the PF. Please post your initial circuit diagram so that we can offer comments on your work.
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