Music Visualizer - TheResistanceBand/theResistanceBand GitHub Wiki

Visualizer Circuit

The music visualizer was created using a MSGEQ7 seven band graphic equalizer consisting of seven band pass filters. We only used the first six of these bands as the seventh band had a center frequency of about 16kHz which is pretty much inaudible. Every other band had a center frequency of 63Hz, 160 Hz, 400 Hz, 1kHz, 2.5kHz, and 6.25kHz respectively.

Each band was then synced to a row of LEDs on the infinity mirror. The lowest frequency band was allocated the widest row of LEDs at the top of the mirror, and each subsequent band was allocated a smaller row following the arc of the mirror. The six bands made up a semi-circle along the circumference of the mirror which was then mirrored to the other side of the mirror.

The visualizer circuit has an audio jack to process the audio output from the Raspberry Pi but it also has a second audio jack to pass the audio to a separate speaker so that the music can be heard.

Why the separate Arduino?

We chose to use a separate Arduino for the music visualizer in order to minimize the latency of both the instruments circuit and the visualizer circuit. Since the visualizer takes the audio output of the Raspberry Pi, these two circuits can operate completely independent of one another.