Pretty self explanatory. It's a $7.99 32x8 panels from sureelectronics. There's a huge thread somewhere about how to use them. I just wrote a simple PC program that does the FFT, and sends the data to Arduino, which displays it.
If anyone is interested, I'll upload my PC program somewhere.
It's already posted. That one only does the FFT on one channel, I've made another version that displays stereo spectrum, I'll put that one up a bit later.
Oh oops, you mean the source code. It's programmed in Delphi 7, would that be Ok? I didn't write my own FFT algorithm, just used someone else's component.
Lex it should be very easy to control more than 1 panel, you need to set the dip switches according to the manual, and use additional arduino pins to choose which panel is the active one.
Yen my code has a self test that lights up all the LEDs when it starts, so if it doesn't work at all it's probably a wiring or other hardware problem...
Edit: oh wait the arduino code doesn't have a self test, my pc program just sends values to fill up all the leds when it connects.