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Thread: prob. with trigerring a counter

  1. #1
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    Default prob. with trigerring a counter

    i was trying to use a 74193 {and 7490 too} counter to count d no. of holes in a disc in an optocoupler arrangement for speed feedback...

    the output of d optocoupler goes into d clk of d counter...
    the prob is tat its not counting properly at al...
    its just showing some stray counts...

    i think d counter is edge trigerred...
    even then how should i make it work with this set up only???
    if u thought u r the only mad person on the planet.......u got serious competition here

  2. #2

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    Perhaps the optocoupler output is fluctuating between on and off rapidly during level transition. If so, passing the optocoupler output through a comparator with hysterisis or a RC LPF with a high cut off frequency might help.

  3. #3
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    sorry for incomplete info...
    the optocoupler output goes to the clk only via a comparator...
    the comparator output is then in turn passed through a buffer{74244}..
    if u thought u r the only mad person on the planet.......u got serious competition here

  4. #4

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    Are all the count down/load/clear pins etc tied to ground/Vcc as required ? Does the counter work properly with a normal pulsed input ? My robot has the output of two optocouplers (H21A1s) directly connected to the interrupt lines on the microcontroller for the encoder feedback and it works perfectly without a comparator or anything. Which optocoupler are you using?

  5. #5
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    tats the whole point...
    ? My robot has the output of two optocouplers (H21A1s) directly connected to the interrupt lines on the microcontroller
    its working like that for me too....

    d prob is tat if i want to count using a counter, its not working.
    if i use a mic to count, it ll work fine.

    but i want to use a counter only...
    if u thought u r the only mad person on the planet.......u got serious competition here

  6. #6

  7. #7
    Super Moderator T-1000 docel's Avatar
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    Addy,
    Can you post your TTL connections? EXACTLY as you have wired them?
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  8. #8
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    sorry for d delay in response....
    ll do dat docel tonight...
    am a little busy with xams and stuffs....
    if u thought u r the only mad person on the planet.......u got serious competition here

  9. #9
    Super Moderator T-1000 docel's Avatar
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    Addy,
    This can wait. Just do the exams as priority :lol:
    Good luck for the Exams!!
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

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