(Apologies for no narration in the video, I was recording using sound directly from the Beagle Board so I couldn't speak into my computer's microphone to narrate)
I used two types of controls: one push button and one accelerometer. The push button turns the DSP on and off. The accelerometer controls the frequency modulator; the x-direction controls the carrier frequency, and the y-direction controls the modulating frequency. I opted to omit the z-direction because 2 degrees of freedom is hard enough to manage in a musical instrument.