I'm kicking around the idea of building a small passive sonar for an autonomous submarine. I've looked through the net for parts and finding a good transducer for converting the sound underwater into an electrical impulse. After looking at parts I got into the piezoelectric materials used for doing this such as barium titanate or Lead zirconate titanate. From what I've read on the web, some of these materials are toxic.

My question is, are there piezoelectric materials that one could to build a sensor from scratch that does not possess the toxic qualities? Something that could preferably thrown in a pool w/ my kids and not give them or me any defects.


1 Answer 1


In general, the microphone should be covered in some sort of waterproofing material (called "potting") that would prevent its materials from ever coming in contact with the pool water. So unless you are concerned that the microphone will be smashed to pieces while in your pool, it shouldn't be a problem

That said, there are some other transducer technologies besides piezo. Ribbon microphones won't suffice, mostly because of their fragility. Dynamic microphones might also a bad idea, because they are generally larger and require more motion than the others.

I'd recommend trying a cheap electrostatic (also called electret) microphone. You should be able to cover it in silicone RTV or "plumbing goop" and still get a signal out of it.


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