I've been experimenting, before wiring anything up to the cube. I had a rig setup for running 8 RGB LEDs on 3.3v, but I decided to undo that, and set it up for 5 volts, because it wasnt working, and I wanted to start with something easier.
So, re-soldered it up with resistors (8 100 ohm on the red, and 150 ohm on the blue and green). I have the cathodes (the negative side) soldered to a wire, and the anodes soldered to resistors, that are soldered to 3 piggybacked 595's. I soldered up a few .1uf caps to where I hook the 5 volts up to the shift registers. I made a couple jumpers to power the 595s from the 5v and gnd pins on the uno, and a jumper from the cathode to the gnd on the shift registers.
No LEDs would light up. just to see if If the LEDs would light, i tried hooking up the 5v to the resistors, no luck, but in the process, I touched the cathode wire with the 5v wire, and some leds lit up. I took the ground wire off of the cathodes, and hooked 5v to it, and it seems to work fine (runs the shift pwm demo).
Im confused though. I double checked everything, and my LEDs seem backwards. The schematic shows pins 1,2,3 as cathode, but on all my RGB LEDs, you hook up 5v to that side, and ground on the other side to light them.
I double checked the datasheet online and the only odd thing I can find is the symbol for the LEDs looks funny, on the blue and green leds there is a symbol that looks similar to an LED next to the regular LED symbol.
Im including the image from the ebay auction
