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LED Flashlights
Daniel Rutter writes: "LED flashlights are better than incandescent, but not for the reasons you might think. I've done a couple of hefty LED flashlight comparisons, now. The latest one, just finished, is here. It covers the neat little Streamlight Stylus 3, five Tektite lights (four of which are waterproof to 1000 feet...), and a couple of old-fashioned filament-bulb Maglites, so you can see how the new technology stacks up. My first comparison is here; it covers a few of LEDCorp's cheap but tough lights, and some of the very, very Star-Trekky EternaLights. They've got microprocessor control, baby!" Nifty. Birthday presents galore.
And an infra-red model, which may come in handy for those among us whose hobbies include telling something to put the lotion in the basket or it'll get the hose again.
What the hell is he talking about?
hawk
A friend of mine has made several flashlights out of LEDs, potentiometers (as dimmers), and short lengths of PVC.
Good idea but I would suggest building a small CMOS oscillator or using a 12C509 PIC and Pulse Width Modulate (PWM) the LED instead of burning up the excess energy in a potentiometer. The batter(y|ies) will last much longer.
One of the very first lights reviewed in this article does focus the LED much like a normal flash light. It is true that very few others do though.
The white is definitely easier to read by though, at least for me. It does reduce your night vision though. Works well for finding cables under a desk in a dim office though.
P.S. I'm sure I have seen yellow LED lights, they might just be micro light sized though. You can definitely get the red ones full size. Good for preserving night vision. I don't really like the way red ones make things look though.
If $20 is a lot of money, definitely borrow first. If it isn't march right out and buy a Proton and put it on your key chain. Proudly declare your flashlight geeakery. Maybe later you can buy a real LED light too :-) I haven't gotten anything bigger then the CCTrek, it is good to read by, and my wife uses it to watch the dog in the backyard. It probably has almost saved it's own cost in bulbs and batteries yet. It would be a bad hiking light though.
However, am I the only person who thinks it is a little bizarre to test flashlights as a hobby? Somehow this behavior does not strike me as beneficial to the evolution of the species as a whole.
Well, after the metetor hits/nuclear war breaks out/other awful event happens, only those people who know flashlights well will survive and have offspring.
The "Police Brutality Edition"?
LOL!
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I have one of these an I love it.
Built like a tank but very light(considering it has 6 bateries in it!)
Each battery is 3V so it has the equivalant of 12 penlights in it!
Comes with 2 bulbs so you can chose between BRIGHT and ^@@#@%^BRIGHT!
Cost me an arm and a leg(and 2 elbows,) but was worth it.
Surefire makes the best (conventional) flashlights I have ever used, and I collect them.
James Ray Kenney mailto:jrkenney@swbell.net
These lights are so bright that you cannot force yourself to look in their direction at night(and it HURTS even on a sunny day!) You can feel the heat from across the room! And yes, they have IR filters to make these a strong source of IR.
Where full auto fire is avaliable(or you are facing multiple advosaries that are spread out,) I agree. The enemy can just spray the area you are in with supressing fire and either you get hit by the fire or an area weapon like a gernade.
Police action is USUALLY quite a bit different.
As the expression goes: 'You cannot hit what you cannot see.' And trust me, it this light is shined in you eyes unexpectedly, you can not help but turn your head(closing your eyes is usually not enough even in daylight,) and by the time you can look back, you can be filled with holes.
James Ray Kenney mailto:jrkenney@swbell.net
Yup. To elucidate further, the serial killer "Buffalo Bill" used IR goggles to see in the dark, so the reviewer must think he needed an IR flashlight.
At one point in the movie (though he's not using the IR goggles at this point), he has a victim he's holding prisoner in his house. She's being held in what appears to be a dry well dug in the cellar. He's starving her so her skin will loosen, and he wants her to put lotion on her skin to keep it from drying out. He lowers a basket into the well with a rope, and tells the girl to apply the lotion. But instead of speaking to her directly, he speaks in the 3rd person and refers to her as "it":
This is what the reviewer was referring to, though it was pretty obscure and I didn't get it until reading the previous post.
--Jim
http://www.google.com/search?q=cache:http%3A%2F%2F www%2Edansdata%2Ecom%2Fledlights%2Ehtm
Stupid job ads, weird spam, occasional insight at
A friend of mine has made several flashlights out of LEDs, potentiometers (as dimmers), and short lengths of PVC. They're great for providing very low levels of light during star watching parties; you can read maps, tweak screws, etc., without destroying your night vision (or that of the people around you). Some people prefer red (lowest energy wavelength); some prefer green (dim light goes further).
Stupid job ads, weird spam, occasional insight at
is in diving magazines. Apparently they are really good for diving (good under high pressure, very low chance of burnout, basically impossible).
You can whack them around and not get burned out.... which is rather important when you're a hundred feet under water in the dark.
Check http://ledmuseum.home.att.net. Dude must spend hours every day playing with LEDs of all shapes, sizes, and colors.
"That's Tron. He fights for the Users."
Isn't this covered in some scientific urban legends page?
IIRC, the reason red light doesn't disturb night vision isn't because it's the "lowest energy wavelength," it's because the color receptors contain organic dyes that only respond to a band of frequencies. If the photon is out of that range, too low *or* too high, the receptor won't fire.
Red is outside of the frequency range of two dyes, and on the edge of the third. (If it weren't, we would see infrared and call *it* "red"). With high intensity red light those cells still fire, and other psychological changes would cause the (brain? eye?) to respond mostly with the color receptors. But with a dim red light the dye-free receptors dominate and there's no loss of night vision.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
An important safety tip about LED flashlights, learned through experience.
If you're driving in an unfamiliar area, e.g., the Olympic Penisula, and pull over to the side of the road to figure out where everything else is (since you know exactly where you are, so many miles south of the National Park on the only major street in the area), do NOT use a red LED flashlight.
It makes major roads disappear from the map.
I got *very* confused, since I knew I had driven on some of those missing roads just days earlier. I swear I started to hear the music from the _Twilight Zone_. But turning on the overhead lights revealed the missing road. Red lines illuminated by a red light disappear, and presumably the same thing happens with the other colors as well.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
When I fly, I tend to use a white LED Photon Micro light to read the multi-colored charts. Its not too bright and I haven't replaced its battery yet after 3 years.
I also carry a Eveready 2AA light with lith Lithium batteries. Its light and very bright. It will light up reflectors at over a 1.5 miles. I also carry a one that has normal Alkaline batteries if I need a semi-bright light.
I've given up on the mag light junk. Sure the case is strong but any little bump and the light bulbs go out. You can't hold them in your teeth (sometimes you need to do that in a small plane). I'm not impressed with their switches and if you have a problem, you can't fix them in the dark. Once they get wet inside, they die. Other than use as weapon, I can't see any good. I have had several maglights and they all failed. The plastic everready is something like 10 years old.
For Diving, I like the Underwater Kenetics 4D cell model and have an 8 AA dual circut light bade by Technisub. Most dive lights use magnetic reed switches so they are completely sealed but if they don't have transistor switches, you burn out the reeds but if you have transistors, they are never off.
Out in the bush, the photon is great. It is easy to carry around (just clip to to your shirt) and it lights up about a 1m circle in complete darkness. Its not too bright so you don't lose your night vision.
He has this whole long review with "scientific" pictures, to get to this conclusion:
Say... one is roughly 14 times brighter?
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Information doesn't want to be anthropomorphized. -AC
Not quite true: there are some modes of fluorescence that involve the adsorption of two photons to yield one higher-energy photon. I have a card in my wallet that adsorbs visible light and IR to give off an orange glow. It's used to detect the output from IR LEDs in things like "electric eye" beams and remote control. It's a lot handier than getting my Starlight gear out.
www.eFax.com are spammers
I have several "photon lights" (which are just bright LED lights), but I don't use them for illumination as for dancing, particularly in rave clubs, which I would suspect is the most common current use for these things.
The blue is by far the brightest. The red is OK, but the white is disappointingly dim. Now if they could just have a purple one that didn't explode on first touch of current... it would be hopelessly dim but quite pretty :)
Zaphod B
Zaphod B
When duplication is outlawed, only outlaws will have
I'm gonna order me some dry ice and overclock the hell out of my flashlight!
Woohoo!
Unfortunately, I haven't written it up. Maybe I'll get around to it someday. The hardest part was disassembling the Maglite: you have to pry out the rubber button over the power switch, and then stick a long Allen (hex) key through the hole in the button and loosen a set screw. This frees the switch/bulb holder assembly, which can then be slid out the bottom of the tube (the end where you put in batteries). I learned this the hard way by removing the snap ring above the switch assembly and driving it out from below! Needless to say, that ruined it, but I learned what to do the next time.
-- ;-)
Kuro5hin.org: where the good times never end.
I was actually referring to the weird properties of tungsten-filament incandescent lamps: First, their resistance increases as the filament gets hotter. Second, their ability to get hot (and therefore produce light) depends on having a sufficiently high resistance. When one is first turned on, it has a low resistance because it's cold and therefore draws a large current. As it warms up, the resistance goes up, and the current drops to a more reasonable level. Unfortunately, this means that if the battery doesn't have enough 'ooomph' to supply the large startup current, the filament will never get hot enough to glow.
What happens with LEDs is that, as the battery nears exhaustion and starts approaching the forward voltage drop, less and less current flows through the LEDs and they become fainter. However, the forward voltage drop isn't the cause: the battery running out of juice is.
The cool thing is that if you matched the LEDs and resistors to the battery, the current will start to drop just as the battery is getting dangerously low, which reduces the load on the battery just when it is running out of energy. This means that the LEDs get dim towards the end, and make that last little bit of energy last a long time. (BTW, this holds for regular alkaline batteries only. Ni-cads will die much faster.)
That's true too: LEDs usually have the highest quantum efficiency (photons per electron) at the lowest currents. This is a double bonus: not only do they preserve the last little bit of energy in the battery, they use it more efficiently. The net effect is that LED lamps gradually dim over tens of hours, while incandescent lamps just suddenly go dead over the course of maybe 15 minutes.-- ;-)
Kuro5hin.org: where the good times never end.
Somebody asked above how well LED flashlights work. Mine is blindingly bright: looking into the beam at close range produces a dazzle effect like a flashbulb, complete with sparkly afterglow. I used highly-focused LEDs: it makes a beam about 2 feet across at a distance of 10 feet. Unfortunately, since the human eye isn't very sensitive to red, the beam doesn't appear very bright, but it's plenty good enough to see with at night. Battery life is very good: I gave up trying to run it down after 24 hours, although there was noticeable dimming by that point. One good thing about LEDs is that they simply grow dimmer as the battery runs down, unlike incandescents which have a tendency not to glow at all once the voltage falls below a critical point.
-- ;-)
Kuro5hin.org: where the good times never end.
A reason that LED lamps are great that is often not mentioned is that they have a very uniform illumination pattern. This is great for reading books in the tent, maps, etc. Most incandescent bulbs simply cannot focus as cleanly. Mine's quite adequate for what I use it for (see my review of the Princeton Tec Matrix on http://www.outdoorreview.com/reviews/Headlamps/pro duct_2333.asp) and it runs around 40 hours on 2 AA's. I never use my Petzl Micro or Zoom these days (anybody want them cheap?)
Dara
So get it straight - the server's unreliable, not underpowered :-).
take a look at this page especially this graph. LED's surpassed incandescents long ago in terms of efficiency, the only hurdle left is to increase the brightness. When Nick Holonyak (inventor of the LED) won the Japan Prize(the Japanese equivalent of the Nobel Prize) in 1995 and was asked to say a few words, he simply pointed to the celing lights and said "all this is going". I think we'll see this happen within 20 years or so.
- "Hear that?! The percolations are imminent! Cease your ingress!"
You need green blue and red LEDs to make white light since LED's are monochromatic. The Blue ones seem to be the most expensive ones and I am guessing the other LED's get much brighter (this means you need more blue ones than greens or reds.) The Blue ones don't last as long as the lower frequency ones do either. I am guessing these won't really catch on until the blue ones are almost as cheap as the red.
One of my favorite toys they have is the radio set wall clock . It checks itself every hour, and is great for things like daylight savings time, etc.
I am sure that this is not the only place to get this stuff, but a second source is always nice.
Check out the Vinny the Vampire comic strip
"It is a greater offense to steal men's labor, than their clothes"
In my area (eastern Phoenix Metro area), they have already replaced many, if not most, of the traffic signal bulbs with high-intensity LED arrays. They appear to be just as bright as the incandescent bulbs, are much more energy-efficient, and have a longer MTBF, resulting in a big savings in maintanance costs. The company I work for makes GPS guidance systems for agriculture ("crop duster" aircraft and ground spray rigs). We use high-intensity LEDs for our steering "lightbar" displays, and actually have to dim them down, even in sunlight, as they can be painful to look at directly at full brightness.
Having purchased a ton of flashlights myself, here are some things you should realize before making a LED light purchse. Most flashlight review sites fail to point out the disadvantages of LED lights:
- Cannot focus the beam, as the reflector is inside the LED itself
- Thus... the beam must be either non-focused, or too focused. Short focus LED lights have a very small range of 30 feet or so, while exceptions (like the PAL light) have such a focused beam that it is useless in close range)
- The "white" light, while impressive and cool, is not that great for night-time viewing. It can ruin your night vision, and does not display contrast as well as the yellow light. (of course, no one wants to put a yellow LED in their flashlight, even if they exist, because it's not "cool")
- pricey. (new technology is always pricey)
So.. my advice is to find a local outdoors retailer that has these lights, or better yet -- look for a flashlight freak like me that has these lights, borrow them, and try them out before you plonk down $20+. Personally, I find that the headlamp Tekka (from Petzl) works wonderfully for proximity lighting, and combined with a conventional Xenon lamp like the Bison, you have your long range covered as well.Just my 2 cents.
They must have also done some silly stuff with the LED selection, wiring and/or batteries, because you can get reds much brighter and cheaper than any blue, and in many different wavelengths.
+5:offtopic,but anti-American
I thought the Nobel was international, prizes like "The Japan prize' would be a sort of subset of all Nobel-Prize-space, I think...
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--hongpong.com
I'm referring to the big, heavy kind. Just so that I can club "Daniel Rutter" in the head, for having that damned popup ad on his site.
-k.
LED flashlight industry insiders have leaked that this whole story was designed to improve the sales on the thinkgeek site. Apparently they aren't selling as well as the bawls, chimp, and mp3 jukeboxes.
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