FFTW3 Sound Spectral Analyzer Example

Using libsndfile, ncurses, alsa-libs and of course fftw3 library, one can write a 200-liner console program in C that performs spectral analysis of a sound file while playing it. This is of course limited to audio files supported by libsndfile, which is currently wav and ogg. But nothing prevents people to do lame -d or use a similar decoder and pipe the resulting wave to the program.

What I am talking about? Look:

https://github.com/jirislaby/collected_sources/tree/master/snd_fft

Phone+Bluetooth=Laptop Control

Controlling your laptop using your phone? Sure:

https://github.com/jirislaby/L2cap

Using Bluetooth, a phone can move with mouse pointer and press mouse buttons on your machine. The only thing needed is to run l2cap from the repository on the machine and the Java app on the phone. Of course l2cap is Linux-specific but it should not be that hard to extend to other systems.