This project has been on hiatus for a while due to work and school, but I'm hoping to get it wrapped up early next week.
Calculating resistance...
12v to 3v with 20 LEDs @ 20mA each(400mA total) puts me at about 23ohms and 5watts for the resistor. Stopped by Radio Shack to see what I could find.
The best combination that they had was 2x 50ohm 10watt resistors. Running them in parallel will give me 25ohms @ 20 watts...a little overkill on the wattage, but better over than under.
FYI: I opted to run the LEDs in parallel so that if one goes out, it will not affect the rest. This will also make it easier to identify a bad LED for replacement.
Another advantage is that the electrical contacts also serve as a frame, making it a tidy package.
Yeah, they're big!
