Very fast VOX circuit?

Discussion in 'The Projects Forum' started by thestraniero, Apr 18, 2012.

  1. thestraniero

    Thread Starter New Member

    Apr 18, 2012
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    Hello,
    I need to design a VOX circuit that will open immediately when mic receives a sound and shut off when the sound stops. I have seen several VOX circuits, but they all seem to remain on for several seconds. I need one that shuts off faster. It's to make a puppet's mouth automatically sync to the sound of my voice.

    Kind regards!
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    I found this thread in the "completed projects" forum.
    As it says it is for completed projects.
    I moved it over here and made it visible.

    You could take a look at some sound to light circuits.
    Those are pretty direct responding to the incoming sound.

    Bertus
     
  3. #12

    Expert

    Nov 30, 2010
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    My first reaction is, show me the schematic and I'll show you which capacitor to change.
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    Even if you could build one I'm absolutely certain you will be unhappy with the results. The reason is that it will be subject to many false triggering events, both on and off.
     
  5. #12

    Expert

    Nov 30, 2010
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    As one that rarely questions the intent of the OP, my opinion is, "Let him experiment".
    The fact that this method is almost impossible to get correct won't stop me from pointing out which part controls the shut-off delay.
     
  6. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    What capacitor ? :confused:
     
  7. #12

    Expert

    Nov 30, 2010
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    The one that controls the shut-off time.
     
  8. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Can a capacitor open and close a mouth?
     
  9. #12

    Expert

    Nov 30, 2010
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    Only if you connect it to a VOX circuit and then connect that to a servo motor.
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Even hobby level 2 transistor "vox" circuits can be tuned to have a fast on/off response. Usually by adjusting the size of a capacitor after the rectifier. I remember making one as a kid with a LED as the output, and with the right capacitor the LED would flash for every word spoken into the microphone.

    I'm sure if you build any simple vox circuit from the web you should be able to tune the response speed you need. :)
     
    #12 likes this.
  11. #12

    Expert

    Nov 30, 2010
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    Thanks for a vote of confidence from a person that has actually done this.
     
  12. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Last edited: Apr 19, 2012
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