Color Organ

Flash-back to the 60's with this 5 channel unit with up to 100 watts per channel.

This unit uses a PIC16F84 with an 8 bit A/D.  The signal from both stereo channels is combined and digitized.  Each of 5 frequency bands is processed using a 16 point FFT.  Then the level of each channel is output as PWM (pulse width modulation) to a set of solid state relays.

The device is housed in a cheap power distribution box.   This provides the 110 volt outlets along with plenty of room for the electronics.  The big trick here was to perform the FFT and the PWM with a single processor.   If you wish, check out the software listing, and see how the two processes are interleaved.   As usual, you can also peruse the schematic allong with the Hex File.   Also, as usual, you are on your own if you actually want to build one of these.