LED RGB Module

Other Hardware LEDs and Multiplexing
6

You can't drive 12V led bar from arduino directly, there are options:

  1. use a transistors - 3, one per color;
  2. use simple transistor array IC ULN2803 or similar ;
    3 specialized led drivers IC, MAX7219, TLC5940, WSxxxxx etc.
    Check out this link, there are small color organ and huge upgraded version - size of a desk, 5 meters RGB strip.
    http://coolarduino.wordpress.com/2011/02/10/color-organ-spectrum-analyzer-on-arduino/