magnets:
but the data sheet says forward voltage is 3v and i think the arduino runs off 5v
will it work? i'm using some 470ohm resistors to help add a bit of resistance.
http://led.linear1.org/1led.wiz
You enter your source voltage (5V) your forward voltage (3V) and the number of milliamps (from the datasheet) and it gives you a resistor value.
From that page, 470 ohms would give you a current of 5 mA.