AVR - PWM to Peizo Sounder

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#1
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Hi,

I want to use a '2313 with serial dataflash, driving a peizo sounder from the PWM output via a LPF. This will play a tune stored at 8kx8 bit samples for a childrens toy.

Does anyone have any experience operating in this way? I'm wondering how well peizo sounders cope with analog audio waveforms.

All answers appreciated.

Cheers
Simon Fisher
Swansea UK

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Piezo transducers have a notoriously "peaky" response. They therefore sound tinny, since they give a significant boost to a relatively small range of frequencies. Most suppliers will quote the resonant frequency of a transducer as one of its parameters.

However, they have other redeeming features which will probably mean that they are fine for this application. They are cheap, small, light, and very easy to interface. They are also low power compared to moving-coil speakers, and at the resonant frequency can be quite efficient.

Solid mounting on a suitable sounding board should increase the volume and broaden the frequency response somewhat.

Sean.