CMKT4 is a rather prolific circuit-bent band that makes awesome contact mics made from recycled bottle caps that they sell through the GetLoFi store. But they also teach workshops on how to make them. They’re going to Maker Faire next weekend and did a hackerspace tour on the way there. Saturday night they stopped at CRASHspace.
The build instructions are in comic form, and they’re actually really good, showing how to build and use the contact mic. They will hopefully be published in Make: magazine in the near future.
They use plastic or metal bottle cap to back the piezo disk, and a pair of plastic bottle caps to house the jack. After dipping the piezo end in Plasti Dip, it’s waterproof and robust. I’ve built a few contact mics before, but this one is the quietest, cleanest, easiest-to-use contact mic I’ve ever used.
Everyone ended up with a working contact mic. They also make a Circuit Bending Buddy kit, which can help with testing various points in the circuits of electronic toys to see where to add switches and potentiometers. CMKT4 also teach a circuit bending workshop, and hopefully they’ll be back to teach that at CRASHspace.