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.
The side-by-side comparison with a Mini-Maglight really got my
attention. So did the pricetag!
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
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.
- posted 18 years ago