Arduino is a very good programmer and it is also open source(The thing I love about Arduino). We are making a Bi Colour LED to run three colours. You can see the video below on how it works. Enough talk, let's make it!
NOTE: All photos and videos are in HD.
Step 1: Things you will need
2. Bi colour LED (http://www.radioshack.com/led): 2.71$
3. Jumper wire(http://www.radioshack.com/Jumper Wire): 5.99$
As my Arduino have male headers, I have to use breadboard and jumper wire. For those who have Arduino with female headers can directly connect LED to thier respective slot.
Step 2: Attaching LED
OK, so attach the RED pin to 9th Digital pin of the Arduino. On Arduino, all digital pins are positive except two last pin after 13th pin.
Attach the green one to 10th and the middle one to Negative also known as GND.
Now building part ends here, attach your Arduino via USB and open your Arduino IDE.