Best and simplest debouncing method

Discussion in 'Embedded Systems and Microcontrollers' started by mikeysela, Jul 28, 2010.

  1. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    Hey Guys.

    I would like to know the bets debouncing method you guys know for a microswitch switching between 3 states and used as an input to a 4017 counter. Is using a micrcontroller the best method? Schmidt trigger and RC circuit? 555 timer circuit?


    The output from the debounced mechanism has to be ACTIVE LOW for the 4017 counter to clock.
    Thanks fellas.
     
    Last edited: Jul 28, 2010
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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  3. mikeysela

    Thread Starter Member

    Jul 24, 2010
    87
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  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    If you don't mind the surface mount chip.
     
  5. mikeysela

    Thread Starter Member

    Jul 24, 2010
    87
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    what do you mean surface mount? I cant put in a PCB?
     
  6. Markd77

    Senior Member

    Sep 7, 2009
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  7. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    I don't see the issue with that though..ill just solder the pins to the holes of a PCB..no good?
     
  8. tom66

    Senior Member

    May 9, 2009
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    You'll find it difficult to solder the pins to the 'holes', because the pins are made to sit on the surface of a PCB. The device is very compact and the pins are closely spaced so you will find it difficult to solder.
     
  9. mikeysela

    Thread Starter Member

    Jul 24, 2010
    87
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    Ok difficult but possible? i dont need anything perfect right now, im just prototyping and want just fairly solid connections.
     
  10. Vaughanabe13

    Active Member

    May 4, 2009
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    It's a SOT package, which is not very hard to solder to a breadboard. Sure it's not as easy as through-hole, but it's definitely doable.
     
  11. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    i dont have surface mounts though. I have through hole board and a breadboard. So ill either solder thin copper wires to the chip leads and stick into breadboard or just solder the chip pins to a hole-board..is that ok?
     
  12. tom66

    Senior Member

    May 9, 2009
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  13. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    im still not sure why i cant just solder wires to the SOIC pins, and then solder the other end to the circular holes on my PCB
     
  14. tom66

    Senior Member

    May 9, 2009
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    You could try, but there's virtually nothing to solder to. Tricky, but worth a shot. How many pins?
     
  15. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    just 4 pins. GND, VCC, IN, OUT.
     
  16. retched

    AAC Fanatic!

    Dec 5, 2009
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    You must not heat the chip too much. Usually the ICs datasheet has soldering times and limits.

    For instance, It will say solder at 430F for no longer than 8 seconds.

    Something like that. Be sure to get good at soldering these types of pins before attempting with your IC.

    You can pull some dead or old ICs off of an old board. Practice with it.
     
  17. t06afre

    AAC Fanatic!

    May 11, 2009
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    I think you are overcomplicating your assignment . Depending on the speed needed these simple setups will do the job in most cases. Found here http://www.ikalogic.com/debouncing.php. And you can use standard components. The fancy Maxim IC may be hard to get. Then you do a design, you must always check the component availability before deciding to use it.
    [​IMG][​IMG]
     
  18. mikeysela

    Thread Starter Member

    Jul 24, 2010
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    do you have a part number on that schmitt trigger. The reason i am "over" complicating things is because the debouncing is the most important part of my circuit, so i want the best solution, and n top of that, i need to use the minimum amount of components for troubleshooting.
     
  19. t06afre

    AAC Fanatic!

    May 11, 2009
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    You can use a 74xx14 "Hex Schmitt trigger Inverter" variant. This is a common circuit that you easy can find in DIP style package
     
  20. Wendy

    Moderator

    Mar 24, 2008
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    Looks a lot like something I posted several years back, it is pretty common and easy.

    [​IMG]

    A simple capacitor across a switch goes a long ways.
     
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