The first idea was thanks to a 555 timer. Tom Morello and Buckethead sound awesome with their killswitches, and DIY guitarists love to play with them as well. What if you didn't have to use your strumming had to use the switch? After some function crunching (I was looking for a circuit that would switch at frequencies from about .5 Hz to about 15 Hz with duty cycles from 25~75, and this was a big help), I got a design for an Auto-Killswitch. Check out the schematics here (PLEASE NOTE: I have not built it, or even tested it yet, so I cannot yet vouch for it's accuracy). The problem I'm finding now is I can't find anyone who sells 1.5M audio taper pots. Most guitar shops only have up to 1M for humbuckers. Hopefully, I will find some. I could just use 1Ms, but I would lose a lot of duty cycle range for most frequencies.
Edit (5/17/11): I just looked back at this schematic, and it is very wrong, so I removed the link. I will post a better one in the future.
The second idea is a little less original, but handy nonetheless. During a bout of wishing I had the funds for one of these beauties, I realized it wouldn't be too difficult to make a loop pedal. With some help from Instructables, I could patch together a loop pedal with 20 seconds of flash memory pretty painlessly. Just need one of these first.
Maybe now that summer is here I will have time to make at least one of these.
