ok start simply.

lets see about some routines (extracted from wherever) to give FFT from live data
no graphics, no faffing, minimal dependencies, simple function, array of results.

in c preferably, then we can use it in various languages afterwards.

MohammadAG wants to do a VU meter using the keyboard backlights, so these kind of functions will help
http://www.youtube.com/watch?v=g3pvdFpA1II