So the parts list is an Arduino Uno $20 An 16x2 LCD Hitachi HD44780 type $5 3 - 10k Potentiometers with knobs$6 each - $18 3 RGB LEDS with resistors....
I thought it would be fun to build one of those RGB based lights for the room. 'Mood lighting' with Arduino. That is an interesting and fun way to learn Arduino. Now remember, these are RGB LEDS. There is RED, BLUE and GREEN inside each bulb! I am controlling them ( aka color mixing them ) with the 3 knobs. One controls the RED brightness, one the GREEN and one the BLUE. I use 3 LEDS to get a brighter output. All the REDS dim and Brighten together with a turn of the knob. Same for Green and Blue. Got the idea? Here we go!
Step 1: Breadboarding
The first step was to setup just the RGB's on a breadboard and connect it to the Arduino Uno. I don't have a pic of that breadboard. Sorry. Then I changed out the 10k ohm bread board mount pots for real knobs for the final build. I bought a circuit board and cut it small with snips and soldered up the RGB's and the resistors. It took me 2 or 3 times to get the layout correct and no shorts but that's the patience aspect of building. It takes practice! Also a Breadboard takes up space, wires tend to fall out etc. There is a Fritzing drawing of the breadboard showing just the LED wiring. Basically the RED leads connect together, the GREEN leads connect together and the BLUE leads connect together. Each color connects to a seperate Arduino PIN as an output. The GROUND of each of the 3 LEDS need to be connected to a resistor and then to GROUND individually! not tied together. Check the diag. I found code I could use at http://owenmundy.com/blog/2010/05/fading-an-led-with-pwm-and-a-potentiometer/ and then tripled the code to control each of the 3 colors. I will post that later.