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I need to get an as loud as possible noise out of a 15mm piezo disc, using only the 3V from Arduino.

I know I will have to make some sort of amplifier circuit, and I have attempted to make a basic one but I don't really know what I'm doing as I'm new to electronics.

JRE
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user2205189
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  • Are you asking for advice on exploding a capacitor? –  May 04 '19 at 12:32
  • @CharlesCowie That could well be what I'm asking – user2205189 May 04 '19 at 12:43
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    Possible duplicate of [I found an audio circuit and I built it just fine, but I find it a bit too quiet. How do I amplify the output so that it is a bit louder?](https://electronics.stackexchange.com/questions/428398/i-found-an-audio-circuit-and-i-built-it-just-fine-but-i-find-it-a-bit-too-quiet) – brhans May 04 '19 at 13:27
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    This sounds like some kind of strange assignment or challenge. The rules you stated are rather strange: Use an Arduino - to initiate the sound on command or ?? Use only the 3V from Arduino - is that a power supply or equipment constraint. Get a noise out of a piezo disc - is there any way to do that other than exploding it? Make some sort of amplifier - from what? You could easily make a voltage boost circuit that would charge a capacitor to a very high voltage you could make a circuit to discharge it into a short piece of wire or a piezo disc or whatever. What are the rules really? –  May 04 '19 at 13:45
  • Also check https://electronics.stackexchange.com/questions/241077/what-will-increase-output-volume-db-on-a-piezo-transducer – dim May 07 '19 at 10:57

2 Answers2

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Loud sound comes from using more voltage on the disk, driving it at the mechanical resonant frequency and mounting it properly (no contact with the disk other than at the mechanical node(s) in an accoustically resonant cavity with the proper size hole.

In a typical bender disk (oilcan resonant mode) the mounting is typically something like a circular knife edge at the null. Contact away from the null point will damp the resonance, reducing the mechanical Q and thus the sound volume.

You can get more voltage by using a step-up transformer or inductor, or use a boost converter to generate a higher voltage rail and then use an amplifier (the latter would probably be more compact because the boost converter could operate at much higher frequency so the magnetics could be made much smaller).

Spehro Pefhany
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The "sharper" you switch the more noisy it should be as higher frequency components are added which make it sound more like a "clap". Maybe driving it in perfect resonance could lead to a higher amplitude but will mostlikely be harder to achieve. You could try a simple full bridge for capacitive loads (web search should turn up some results). Actually a half bridge built as simple push-pull with very basic mosfets could be fine as well. To achieve "sharp" switching you could try simple hard mode switching which is basically "on-off".

Christian B.
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