Nothing special. ATmega8 just listens on USB. Lighting of every LED depends entirely od PC. This allows me to display sound bars, reversed sound bars or dots. Or the device can be used for PWM ambient lighting of computer. Now I'm focusing on software on PC. The idea was to make a device as much simple as possible.
The entire VuUsb package can be downloaded on the end of this page in attachments. I built just a prototype so there is no circuitboard or even full scheme. There's a readme file in the package with another info.Here you can see final working device by modules:
This is first prototype: