pedalSHIELD UNO is a lo-fi programmable guitar pedal that works with the Arduino UNO / Genuino UNO Board. The project is Open Source & Open Hardware and aimed for guitarists, hackers, and programmers that want to learn about digital signal processing, effects, synthesizers and experiment without deep knowledge on DSP, electronics or hardcore programming.
You can program your own effects in C/C++ or get inspired using the ready-to-play effects from the online forum.