check it out, my shot at an arduino based synth:http://tthheessiiss.wordpress.com/
right now the feature list is as follows:
* atmega328 processor
* 12bit DAC sound
* 16 LEDs run through shift registers for sequencing control
* LCD display
* rotary encoder for multi purpose tweaking
* stylophone keyboard
* expression control through body switches
* wireless receiver and transmitter through infrared light (control your synth with your remote control!)
* passive volume control
* 5 navigational keys and 1 home key (can be expanded with shoulder keys)
sound circuit and code based on the arduino pocket piano project.
making PCBs now, will soon have some more tight versions of this little frankensynth!
the plan is - with time - to create a kit of this prototype, if you have feedback or ideas, please share.