The Arduino is an inexpensive microprocessor board useful for experimenting with hardware.
Scratch is a somewhat visual programming language, available for free.
Here is someone who put these two together and created an inexpensive Theremin-like musical instrument. It may be limited in scope right now but I am sure in a few years' time, someone who is enthusiastic about its possibilities will demonstrate Hindusthani Music (think long slow meends and jarus) on this.
s4a.cat/downloads/s4a-sample01.pdf