Help with Drawdio Clone

Discussion in 'The Projects Forum' started by morningstar, Dec 27, 2013.

  1. morningstar

    Thread Starter New Member

    Dec 26, 2013
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    I've been trying to replicate Adafruit Industries' Drawdio but with a simpler design/lower part count. The attached circuit works when mounted on a pencil but the volume is really low!

    I've googled around and saw that in similar relaxation oscillator based siren circuits sometimes a small electrolytic is put between the emitter and collector of "Q2" in the attached schematic. I tried it out with a 4.7uf and the volume improved a lot, but still isn't anywhere as loud as an actual Drawdio.

    I've been to other forums where the voltage was blamed, but the original Drawdio also runs off of 1.5v and it manages to be sufficiently loud, so that isn't it. Can anyone explain why the capacitor improved the volume and what else I could try to make the attached circuit louder? Thanks!
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. morningstar

    Thread Starter New Member

    Dec 26, 2013
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    Thanks for the reply!

    The original Drawdio design does use a low power 555 chip, but I'm trying to create a Drawdio clone that doesn't use any IC's. The circuit I attached works but isn't as loud as a legit Drawdio, and I'm trying to figure out why/how to make it louder.
     
  4. morningstar

    Thread Starter New Member

    Dec 26, 2013
    3
    0
    Well, I've also just added a 10uf capacitor across the speaker leads and the volume has sort of improved again. It's inconsistent though, it sort of switches between being really quiet and being decently loud.

    I'm just guessing with this capacitor placement, can anyone explain how/why these caps are affecting the volume of the speaker output?
     
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