I want to generate electricty from sound but i don't know how to detect the sound

  • @Shaun, I'd like to specify that "this is exactly what [dynamic] microphones do". Also, you'll get more amplitude out of greater SPLs, therefore I'd venture to say more power. – Justin Huss Oct 26 '13 at 17:59
  • good caveat that I forgot to mention, Justin. thamks. the greater SPL point won't make a significant difference in the voltage delivered to an exterior load though. even at max, these mics produce miniscule amounts. – Shaun Farley Oct 26 '13 at 18:00
  • I will admit to not knowing what the output voltage is on solar cells though. so who knows. it might be possible to pull off something similar with microphones, but I have my doubts. – Shaun Farley Oct 26 '13 at 18:03
  • Why do you want to do this? I ask because I'm trying to work out whether to flag this question as off-topic. – Joseph Harvey Oct 28 '13 at 6:42
  • This is an interesting question. Could be a setting for a scifi story set on a particularly noisy planet with the people living underground drawing the power from apparatus above. :) – user6719 Oct 28 '13 at 13:42

From your question it's not clear to me if you want to win electricity from sound or just convert sound into an electrical signal? Many microphones need electricity to function correctly (phantom power), and a preamp that boosts the signal, requiring more electricity.

In theory it's possible to use a dynamic microphone or a piezo element to create electricity without spending it, but the gain will be minuscule. You'll need to add components in the circuit that turn the very fluctuating voltage you generate into a usable, stable voltage. Such a circuit is not 100% efficient, so part of the energy will get lost in the process (it gets converted to heat).

If you are really set on doing this, piezo elements are a good starting point. If you want to turn air pressure or movement into electricity, and you have a possibility to mechanically or physically amplify the pressure or movement before it gets converted, that might be another option worth exploring.

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  • I want to win electricity from sound to be used for running devices not just convert sound into electrical signal – Nour Oct 26 '13 at 14:12
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    @Nour - the amount you'll need to do that can't be generated from any single device that exists right now. You would need a massive array of transducers and the additional components EMV mentioned. It will also be highly inefficient. You'd probably be better off investigating a solar application for whatever you're trying to do. – Shaun Farley Oct 26 '13 at 15:32

This is exactly what microphones do. They convert acoustic waves into electrical signals. Dynamic microphones can do it without an external power source. Mind you, the voltages generated by microphones are pretty small. That's why preamps are used to increase the gain. I'd start there.

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