OT: LED lights revisited (long)

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
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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
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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.
Reply to
Don Foreman
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About the same time as the thread was running, I found and bought an LED book light at Costco. I've been using it for about an hour every night for the past two months and it's still on the first set of batteries. It hasn't even begun to dim. It'll be interesting to see how long thay last.
Right off the top of my head, I'd say it will pay for itself by the time it's depleted its first set of batteries. My old incandescent reading light went through batteries like popcorn at the movies.
I also put a Photon II light on each of our vehicles' key rings. The light they provide is nothing short of amazing. I'd recommend that everyone have an LED keyring light. You never know when you'll need it.
The Candlepower Forum is a wealth of LED information.
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...as is Flashlight Reviews
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Reply to
Orrin Iseminger
Snip Thanks Don for this bit of insight. My bicycle lighting system includes 2 Harbor Frieght's 15 LED 20 dollars, mag like flashlight, modified in my machine shop to use AA cells.
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I have heard that these light are pushed hard. So a year from now I can afford to replace it, maybe at 5 dollars, I paid 40 dollars for a 7 LED flashlight more than a year ago.
Reply to
Bill Cotton
They are good! My old Mini Mag Light is EOL, and I was looking for a replacement. The local hardware store had a 3 LED headband light for $8.00 CDN. I snapped one up.
Steve R.
Reply to
No, it is fastened to the key ring with another metal ring about 5/16" diameter.
I would have gotten Photon III because they're easier to change batteries, but their sequence of modes sounded like a PITA.
Reply to
Orrin Iseminger
i have cheapies, "Coast", not listed on the url you gave. they attach to the keyring with a metal 1/2" ring but from that to the light with a plastic swivel. i just wondered how these might hold up (the swivel).
thanks! --Loren
Reply to
Loren Coe

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