divindavid said:also i have two small questions
what do i use to power this i think it sayed it needed 6V and i know i could use a 6V hobby battery but what about anything smaller
what is i going to put this is i am thinking of a hobby box but i am not to sure or an altoids can
The best solution I've seen so far for powering a LM317 constant current source driving a DIY red is 6 NiMH cells. It doesn't much matter what size cells, so long as they can source 250-300mA. Six 1/3 AA cells will usually fit into a two AA holder. An easy (But more expensive) way to find these locally is to look for cordless phone batteries like this one. But I'm sure there are other battery packs containing 1/3 AA cells.