Here is a rough (aka bad) video to demonstrate how it sounds with no effects:
Also, here are some references and inspiration:
Step 1: Materials
metal casing from hanging work light
1" piezo buzzer
thick felt with adhesive back
two different gauge weed eater strings (I used .65 and .80 that I tuned to E and B)
various nails and screws
a pencil split down the middle
As far as the paddle goes, I used a SeaSense from Wal-Mart, but I'd suggest to try to get one from a sporting or camping store mainly because mine seems flimsier than others of the same brand but from another store.
Also, the machine heads can be either for a bass or guitar; a guitar machine head can hold a piece of .80 weed eater string with no problem.