[racket] Audio input

Hi all,

A couple of my students are toying with the idea of generating pseudorandom numbers from ambient sources, and want to try using audio as a source.

They are doing it on Linux and not concerned about portability, and they just need to be able to grab some input on demand, so my initial off-the-cuff suggestion (advertised to them as such) was to open /dev/dsp for reading, read the number of bytes they want, and close it.  I don't know enough about Linux audio (or audio hacking in general) to know this is a workable way to get it done in Racket, so if any of you have done enough audio I/O work to confirm or refute this idea, or offer a better way, please let me know.

Thanks!

Best,
Jordan