I doubt you’ll be adding this to your home recording studio rig anytime soon, but it’s still cool nonetheless. This microphone was made out of a piezo pickup, 1/8th-inch jack, and a tin can. I never thought about it, but yes, I suppose this is about the simplest microphone one could ever build. No clue on how the quality of the mic is, but it looks like it could give off a real vintage sound.
Tin Can Mic [MAKE]
This would not work. How does a sound vibration convert to an electrical signal?
The peizo electric piece picks up the vibrations caught by the tin can. These peizo pieces are used in acoustic pickups for instruments too.