There are hundreds of mics out there. We have seen how to use a standard dynamic microphone. Today we will see a very cheap type of mic that anyone can buy for $20, or build for $2.
This is a large contact mic (~2 inches diameter). The red and black wires are soldered to the two (or three) wires inside an audio cable. The mic must be attached to or placed on a flat, smooth surface that vibrates. The mic can be taped to the surface. The best surfaces are metal, dense wood, or any material that resonates when struck or scraped. Some contact mics are contained in an enclosure and stuck to the surface with a putty-like substance. (We have one of these in B33 as well.) Contact mics output a line-level signal, so be sure to set the input to "line". The one caveat is that contact mics tend to pick up interference from other electronic sourses.
In case you are wondering, here is a diagram of where you can put contact mics on traditional instruments...