This LED guitar has a 555 circuit that allows the leds to pulse at a desired rate, or stay on all the time. Its only powered off a 9V battery that i've concealed in the back panel where you would change the strings (so its somewhat easy to change) This could make for a visual "beat", or strobe when playing.
First i had to make a new front panel for the guitar to hold the extra swiches and POT.
Next i cut out the new piece and cleaned it up. Also I etched one side to create a fogged effect for the backlighting.
Here is a quick schematic of the design. Pretty basic 555 timer design, which can be changed for various results. I put together a small cludge board with each color led on it. So there are four boards all together for a total of 16 LEDs.
Each color can be turned on independently, or have them all on at the same time. Combining colors gives you combinations of colors inbetween.