The recent thread on this topic got me interested in exploring these devices. I'm now working on a ringlight for my microscope using white LED's and little collimators -- but that's another story.
Check out
Key elements are the housing, the LED used, the optics and the elex. I and most RCM readers can machine and knurl an aluminum housing. Anodizing is easy enough and recommended for nice smooth-running fine threads in Al. O-rings are no mystery.
I've discovered that the LED and collimating optic (molded acrylic) can be bought for $14.63 from
That leaves the elex, but I think I can manage that OK. Might be another 5 bux.
I want mine to have adjustable brightness to match the illumination (and battery consumption) to the task at hand. I'm a bit suprised that these pricey "tactical" or "survival" lights don't provide that. it's a feature I'd definitely want if I cared about "tactical". Sometimes ya want all the light ya can get, other times a faint glimmer is sufficient and even preferable.
My Luxeon Star arrived today. It definitely outshines (pun intended) my MiniMag at WOT (350 mA) while drawing about the same current.
I'm a bit skeptical about the claim made on the abovementioned website that the reviewer could see out to 75 yards, but perhaps some of these flashlights overdrive the hell out of the LED's. That surmise is supported by the fact that he said it got noticably warm. Given nominal life of 50K hours to 70% of original brightness at rated current, I guess one could overdrive it quite a bit (with adequate heatsink) and still get acceptable lifetime. A household bulb typically lasts 1000 hours, krypton flashlight bulbs less because they run hotter. I consulted with a former colleague who happens to be the guy that invented the LED. He said his rule of thumb is that every LED has so many photons to emit, spend 'em as you will.
The real surprise was when I turned the Luxeon down some, using a lab bench supply to drive it. At 10 mA and a distance of about 30 inches it illuminates a whole page of a hardcover book brightly enough to read very comfortably even though my night vision sucks anymore. I could still read readily at 2 mA but I might not want to read for more than an hour or so that way. At 10 mA it would run at constant brightness for 178 hours on 2 alkaline AA cells. At WOT it'd only run about 5 hours. Macht nicht most of the time, since batteries are cheap, but in a lights-out sit or when 40 miles of bad road away from a store one might want a throttle: plenty of light when it's needed, plenty of battery when less light will suffice most of the time.
Elex will happen ... eventually. What I lack in lazy I make up for in slow. First rule of retirement: NOTHING IS URGENT! (Well, not yet anyway, at age 61...)
For the impatient and electronically-inclined, Maxim, Zetex and Supertex offer surfacemount (tiny) driver chips for white LEDs, They're not intended for use at 350 mA but probably could be adapted.