I built one a while back. It has 1 Royal Blue 3W emitter, and one 1W White star. I used a LM317 AA'ed onto an aluminum plate, along with the star and emitter. I built a switch for 2 levels of output, low and high. The thinking was on low I could have the Royal Blue on while I drive to cast a nice glow, but alas, it was still too bright at ~200ma. Full power they both get ~890ma, so the 1W is quite overdriven. The white looks brighter than the stock light was, and whiter of course. It's a Q2K. The royal blue is super bright, and a real attention getter. What's cool is just 1 RB lux3 is way brighter than any Car Neons I've had, and it is hidden in the dome light!!!
Yes the plate gets scorching hot, and yes probably really hot for the luxeons, but they'll last plenty. My domelight will shut off after 15mins even if left on so no worries about the battery. The ciruit is inefficent, but cheap! And it keeps constant brightness since it regulates.
What's weird is I can detect a slight strobe when the car is not running, like 70hz or so. But turn on the car and it is steady light... WHY IS THIS? It's not really noticible, but weird!!!
Click here for my post. I don't have pictures of the actual unit that was finished, since the floppy that had the pics on it was dropped or corrupted somehow /ubbthreads/images/graemlins/frown.gif
red_robby: only 1 lux and 1 resistor? what value?
I've found 5mm led's resistored down on car voltage to be dim enough for indicator lights don't change with voltage changes in the car. Unless my blinkers don't make my voltage dip, which I know is the case because I have a volt meter and it's rock solid now.