microphone instead of sensor

Discussion in 'The Projects Forum' started by Eplanet, May 31, 2009.

  1. Eplanet

    Thread Starter Active Member

    Oct 25, 2007
    42
    0
    hi dear friends
    i want to make a shock sensor with microphone but you know the microphone take any voice even small i wont operate with small voice.
    can you help me and any idea?
    thanks
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Are you going to try to measure G forces? Sounds like an interesting idea, but the little stickons do a fair job, assuming this is what you're talking about.
     
  3. Eplanet

    Thread Starter Active Member

    Oct 25, 2007
    42
    0
    hi
    no G force i want to starting alarm with touch a device that capacitor microphone inside it.
    thanks
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    If you "shield" the microphone from surrounding sounds it could work.
    You could place the microphone in a closed box attached to the part you want to sense.

    Greetings,
    Bertus
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    That and low frequency filtering, to kill ambient noise like talking.
     
  6. Eplanet

    Thread Starter Active Member

    Oct 25, 2007
    42
    0
    have you any simple circuit ?
     
  7. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Electronic drums use a piezo transducer as a shock sensor, not an electret microphone.
     
  8. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Nope, think simple RC filters though.
     
  9. Eplanet

    Thread Starter Active Member

    Oct 25, 2007
    42
    0
    what is your idea about this circuit but i know this is have low sensitive
     
  10. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Hi Eplanet,
    If your sensor is a piezo transducer then it does not conduct current to bias the pin2 input of the opamp. Also the 1M resistor applies positive feedback making an oscillator.

    If the opamp was biased properly and had negative feenback then its output would just be a short "tick" which is not long enough in duration to activate a DC beeper.

    Here is the schematic of an e-drum preamp that uses a piezo sensor. the output pulse is stretched with a capacitor and drives the input of a computer to make any sound you want.
     
Loading...