Laser Security Alarm problem

Discussion in 'General Electronics Chat' started by maii03, Feb 27, 2013.

  1. maii03

    Thread Starter New Member

    Feb 27, 2013
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  2. tshuck

    Well-Known Member

    Oct 18, 2012
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    Whether or not this is possible, using the existing hardware, depends on the hardware used. If it has a microcontroller, odds are you won't be able to change it without replacing the controller.

    Do you have a schematic for the "Photo sensor controller"?
     
  3. maii03

    Thread Starter New Member

    Feb 27, 2013
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    http://tinypic.com/view.php?pic=25g44eg&s=6

    Hi tshuck, thank you for checkin' out my post.
    I took a picture of the photo controller for the meantime while I'm trying to obtain its schematic.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Can't see a schematic.

    Please attach as a .PNG using the paperclip icon (top row, beside the A for font color) in the advanced reply editor.

    First problem is using a photoresistor instead of a phototransistor for the detector, I'd also guess you have a large capacitor RC that needs to be charged before the comparator/transistor can switch on to power the buzzer.
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    I would start by monitoring the dc voltages across the capacitors, and see which one charges or discharges in the same time as the delay, then change the capacitor for a smaller value , lower in capacitance.
     
  6. tshuck

    Well-Known Member

    Oct 18, 2012
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    Yeah, look s pretty easy to modify.. Dave's suggestion seems like a sound one...
     
  7. CVMichael

    Senior Member

    Aug 3, 2007
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    For testing, you can just put a resistor in parallel with the capacitor, start with a 100K resistor, and see if the delay time changes, if not, lower the resistor to 10K, and check the delay time, and so on...
     
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