Arduino music leds, USB Style :)

So this guy made leds dance using the Arduino:

but personally i think this is much cooler:

How could I modify the dance room processing sketch to match the effects of the light box?

Because the light box depends on the voltage fluctuations from the headphone jack. The trouble I’m having is figuring out whether voltage increases based on volume, tone, or bass. And how can I imitate that fluctuation with the processing sketch?

Be a fun project for us to try out. I will probably make an instructable out of it.

Have Fun and Thanks!

Taking a shot in the dark here, I would think that voltage increases with volume.

I would assume the pitch, etc. are controlled by the frequency at which the voltage is transmitted.