Using ohms law and the power formula I came up with (I guessed the 3volts):1 watt LED = 3v, 9ohms and 333mA
The power source would be a 12v from the car battery and the Arduino needs a power supply of ? and outputs of the pins is ?.
I would need to run all the bulbs in parallel since voltage is common in parallel
and I would need to use the voltage divider rule to get from 12v to 3v?