The music visualizer [1] is a capture client built on JACK [2] which takes realtime audio data from the input channel of a Raspberry PI 2 (plugged to a CastioTone) and then draws its output to the RGB LED matrix through GPIO pins [3].
References:
[1] Music visualizer by Fourier Art ( http://fourierart.com )
[2] JACK - ( http://jackaudio.org )
[3] Controlling RGB LED display with Raspberry Pi GPIO by Henner Zeller ( https://github.com/hzeller/rpi-rgb-le... )