I have made contact microphones for use in percussion and noise endeavors for some time. These microphones transduce the vibrations of solid objects into audio signals rather than changes in air pressure like most microphones. This makes them great for capturing unique sounds from common objects, for use in experimental and foley sound work, or even as utility microphones for isolating individual percussion instruments for amplification or processing.

I sell these mics as product called Lil' Dipper, which are my latest and greatest versions. Combining multiple common approaches for DIY contact microphones, they are fantastically capable, great sounding, affordable, and 100% made with love by hand! The mics feature dual piezo elements and are available with TRSF or XLRM connectors. The dual piezos placed in opposite directions create a pseudo-balanced signal which provides very high headroom with low noise, great for noise music and amplifying very tiny sounds with lots of gain. They are covered in a liquid plastic, offering water resistance for exploring shallow underwater sounds, amplified rain, and many other wet applications.

If you're interested in purchasing a microphone, they are available from Perfect Circuit.