Light-Sensitive Wah Effect

The wah pedal: a brilliant, powerful sound effect housed in a difficult-to-control box. Who has that much control over their feet, really? The pedal's onomatopoeic name comes from the difficulty that guitarists have in creating any other sound with it. Here is one solution:

Technical info: I have cheated slightly in making this effect, or at least deviated from the obvious route. Purists might have expected me to pull apart a Cry Baby pedal and replace the rocker pedal section with a photoresistor. Instead (mainly because I don't own a proper wah pedal), the Arduino reads the voltage across the photoresistor every few milliseconds and sends an appropriate MIDI control change signal to my Behringer LX210, a cheap-but-loud guitar amp which has built-in effects and inexplicably (but commendably) contains MIDI in and out ports, giving control over every single setting on the amp. As before, MIDI communication is achieved using the Arduino's serial port via a MIDI socket and some crocodile clips.