1. shankarNITIAN

    Thread Starter New Member

    Mar 16, 2009
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    this is a circuit diagram of a two way counter. http://www.scribd.com/doc/13394345/shankarnitian [​IMG]i would be glad if someone could explain me the functioning of the 1k resistor in series with the green and red leds,function of 10uF in parallel with reset switch,the significance of using two 22pF capacitors with the crystal oscillators ,and how can i interface the output of the microcontroller to the seven segment display?
     
    Last edited by a moderator: Mar 18, 2009
  2. shankarNITIAN

    Thread Starter New Member

    Mar 16, 2009
    5
    0
    this is a two way counter using ir leds and phototransistors for identifying an obstruction and count up /down according to entry/exit of persons.i feel the LM 324, keeps comparing the two outputs and if there is an obstruction,the output goes high whic is identified as a '1' by the microcontroller.is it correct?
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The 1K resistors limit current through the LED's. The capacitor debounces the push button. The 22pF caps load the crystal to let to ring properly. If the light is blocked, the output of the op amp will go high.

    I remove the "< >" so the link works.

    You will need to connect those output lines to the 7 segment displays according to the display pinouts. You can just go from segment a through g. Use 330 ohm resistors. The segments will turn on when the output pin goes low.
     
  4. shankarNITIAN

    Thread Starter New Member

    Mar 16, 2009
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    0
    has the 1k resistors anything to do with the concept of pull up/down?could u please elaborate "" The 22pF caps load the crystal to let to ring properly"" a bit more?
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
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