sorry for reviving the thread but posting a new one is more harm i guess.
I've been working on a similar project witch involves lots of programming witch i like.
I've build mine similar to the drawing on the first post, and i use comon cathode 5mm RGB Led's 5v 20mA.
I hocked 3 Leds to my arduino but i didnt use the "MOSFET" thingy cause i don't know what that is.
Point is my LED's don't produce the colors they should.
Simple Red, Green and Blue work perfect but anything in between dosent work as it should.
Instead of getting Yellow light i get two circles on my wall, one is Green and the other is Blue. Is that how it's suposed to be?
I read lots of forums and people saying with RGB leds and analog pins with PWM you can control each pin's output and therefore get any desired color.
I'ts exacrtly what I'm doing except 0,255,255 dosen't produce Yellow at all..
Any ideas, could it be the "MOSFET" thingy i'm not using? :-/