Piezo analog to digital

Discussion in 'The Projects Forum' started by Member02, Sep 23, 2010.

  1. Member02

    Thread Starter New Member

    Mar 23, 2010
    hey guys, I'm working on a bunch of pieces to a larger light/laser show machine. But anyhow I'm looking to get a cheap input of sound to feed the sequencers, but I'm looking at the workings of the piezo thinking perhaps it cannot be done.

    Right now I need help conceptualizing how to get low amp, low voltage signal to be split up and sent to different sequencers.

    I'm thinking of rectifying the ac output from the piezo first, as it is varying from 2v to 20v (20v being 110dB of music and 2v being listening level around 90dB, so this is the range I want to be accepting) Then I was wondering, how do I possibly turn this towards logic? the voltages vary too much.

    I am trying to make it all logic gate design, though I love programming, I just don't want my arduino to be tied up with this silly fun machine.

    Dealing with 5 and 0 and true and not true I was wondering if anyone has any ideas of suggestions about splitting up the input. I was wondering also if it's possible to split this signal into three signals, using some filters, to output a low freq logic signal, a mid freq logic signal and a high freq logic signal, but I'm not sure where within the circuit design this would be best to place.

    Any help would be appreciated, thanks! I will eventually likely add pics and more to this as I slowly build everything up.
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
    You'll be better off filtering out your frequencies while still in the analog stage, easier and less expensive in my opinion.
    Member02 likes this.
  3. Member02

    Thread Starter New Member

    Mar 23, 2010
    Good idea, as I saw it would be hard to do after I built my DAC. I am liking this though, super cheap, pretty <snip> effective as a mic too, picks up everything and spits it out as a nice ac voltage. A full-wave rectifier worked wonders, and I was able to get a 0 and 5v output tunable as needed with a 10kohm 20 turn pot. But yea I will definitely split it first.

    I was wondering, is there an ideal way to split and increase the signal again? you guys seem to have all the right ICs memorized as a community, at the moment I would probably do some half <snip> approach to this.

    so right now I have the rectified and flattened peaks circuit going to an op amp to act as a tunable comparator. but eventually I want to have three op amps from the original signal, all working on different freq range. This will in turn move mirror actuators that will inevitably be home-made, to relocate laser beams into "stages" where they will create effects in response to certain outputs from the piezoelectric mic.
    Last edited by a moderator: Sep 26, 2010