Playing With Piezo Crystals

I updated the swarmed post.

I’ve been playing a little bit with piezo crystals. Some good how to videos include:

• Piezo Crystal Howto Video
• MAKE: Magazine Piezo howto

You just need soda ash (baking soda that you cooked) and cream of tartar to make these crystals.

So I made some:

I hooked them up with alligator clips:

I had to amplify the crystals to hear them:

The amplifier I used is described here: Fet Amp. It is very easy to source the parts from digikey.

I made a more permanent mic out of a crystal that I soldered:

I had TERRIBLE mains hum and I tried dealing with it in analog with a Twin T Notch Filter using a 1uF and a 2.2uF and 680 ohm resistors to cut out 60hz. It did not work well:

I eventually made some csound code to dehum for me.

Here is a demo of the big crystal with the tinfoil on the right channel and a 4.5k piezo contact mic on the left channel. There’s a toothbrush involved as well.

• Ogg File – loud!
• Video presentation of this ogg file