So I have this idea.  

In my car is an LCD stereo that has several RGB LEDs in it's face around the volume knob, the tuning knob, and a few buttons.  In the stereo's configuration settings, you can choose what color (7 options) you want these LEDs to display, or an 8th option which cycles through colors.

I really like the idea of adding other lights to my car, just for geek/bling/rice value/for the hell of it/because I can.  How could I take the signal for one of those LEDs and use it to CONTROL a small circuit which in-turn would POWER the other LEDs I want to add?  I do not want to try to draw enough current directly from the stereo's circuits to power many more LEDs.  I am thinking of maybe 20 more LEDs.

A little about me:  I could likely print a board, if I really had to . . . I can solder . . .  I understand basic circuits but have a little trouble with the math behind things like multiple resistors and voltage drops etc. I have worked a little with LEDs before, including RGB. I am over 30..

Let me know what you think?

Michael, from "DC"