Well, here is a schematic for a working 8-bit guitar pedal. The cost in parts WITH the housing is pretty low. Most of it is the Arduino that you must buy to program it. It consists of two different preamp stages, with a switch to select between them. The first is an Infrared optocoupler that sends a 0-5V guitar signal out. The second is a BOOMY and BEEFY Darlington transistor that does the same. The microcomputer runs a routine that blesses the amped guitar sound with a crazy delay and/or fuzz effect before outputting an 8-bit signal. You can effect the software with the pot that goes to the Atmega.
I made a discreet Digital to Analog converter using an R2R resistor ladder, and I added a switch and a pot at the output to dial in the different tones.
All in all, this thing sounds fantastic. It gives the signal a HUGE boost, and allows you to dial in everything from Nintendo sounds through deep booming octave bass notes (and all kinds of craziness in between).
In keeping with the Arduino mission, I am more than happy to share/help anyone that is interested in this project.
Hit me up.
Pete
