# DIY 500 lumens headlamp!



## eart (Nov 16, 2006)

http://static2.instructables.com/pub/F2J/W932/F2JW932TZTEUKIKP7V.medium.jpg


Check it out: http://www.instructables.com/id/E2K9BN5EDKEUBYRD9V/?ALLSTEPS


It's pretty crazy.


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## TigerhawkT3 (Nov 16, 2006)

This belongs in the EL/HL/Hyb forums.

Pretty cool - interesting tradeoff between brightness and color rendition.


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## wasBlinded (Nov 16, 2006)

That is very impressive. This guy shows a lot of original thought and ingenuity. It does make me wonder what it would be like to ride at night on the trail with a cyan headlamp. Seems kind of weird:thinking: , but maybe it would work just fine.


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## nakahoshi (Nov 16, 2006)

no hotlinking


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## mcmc (Nov 16, 2006)

So this guy must be a CPF'er, right??


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## eart (Nov 16, 2006)

nakahoshi said:


> no hotlinking



I thought about it, but then i realized that if anything I'm _driving_ traffic to their website. That made everything ok.


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## IsaacHayes (Nov 16, 2006)

It's against CPF rules though to hotlink an image from another website.

I saw the pic and thought, wow, cyan? Then I saw it really was! I doubt 500lumens since those are only lux1, that would mean 120lm per star! But he is re-rating them for how your eyes perceive the color as brighter. But still unless he got some R bin and drives them at lux3 levels, I don't think it's that high. They gotta be pushed pretty hard.

The pic looks like real cyan but cameras always do that. I wonder what color it is in real life and what bins he used? I love true cyan!

I bet it sure is a site to behold and freak out "normal" people  I know my lights spook others.


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## TigerhawkT3 (Nov 16, 2006)

Just save the pic to your computer, upload it to an image host like www.imageshack.us, and hotlink that. That'll drive traffic to their site without sucking up as much bandwidth.


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## billw (Nov 17, 2006)

The "500 lumen" number is derived rather creatively. They apparently start with about 50lm/w for
the 1W cyan luxeons, multiply by 2.5 because of the increased eye sensitivity at that frequency,
then Double again because they're overdriving them to 2W and assuming the same 50lm/W
number because of their "adequate heatsink", and then multiply by four for four separate
emitters. The whole cyan idea is "interesting" and this does indeed sound like a very bright and
effective headlamp, but "500 lumens" is "marketing speak."


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## Sawtooth (Nov 21, 2006)

I may have missed something there, but I really don't think that cyan will be useful for night vision (aka scotopic vision) at all. That wavelength destroys the rhodopsin that makes the rods (rod cells) ultra-sensitive at night. You need red light to preserve scotopic vision. The reason that things look greyish (what some might consider bluish) at night under low light is that the rods only have a single type of light sensitive pigment (cones have 3 to give us color vision). 

You could certainly get >500 lumens out of 4 Red/Orange Lux IIIs though. They deliver 190lm each. (But are apparently heat sensitive and lose alot of efficiency at higher temperatures).

I think the mod is cool, but the guy's info on night vision seems wrong to me -- cyan is not a special wavelength to see better at night....


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## Sawtooth (Nov 21, 2006)

Sawtooth said:


> I may have missed something there, but I really don't think that cyan will be useful for night vision (aka scotopic vision) at all. That wavelength destroys the rhodopsin that makes the rods (rod cells) ultra-sensitive at night. You need red light to preserve scotopic vision. The reason that things look greyish (what some might consider bluish) at night under low light is that the rods only have a single type of light sensitive pigment (cones have 3 to give us color vision).
> 
> You could certainly get >500 lumens out of 4 Red/Orange Lux IIIs though. They deliver 190lm each. (But are apparently heat sensitive and lose alot of efficiency at higher temperatures).
> 
> I think the mod is cool, but the guy's info on night vision seems wrong to me -- cyan is not a special wavelength to see better at night....



But of course, Lux III R/O probably also emit at too low of a wavelength to preserve night vision... You probably need to go to red LEDs...


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## Meduza (Nov 21, 2006)

No cyan is not a special wavelength at night, but your eyes are much more sensetive to cyan than to other wavelenghts.


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## Martini (Nov 21, 2006)

Yes, your eyes are very sensitive to cyan, but that's not really a good thing. The cyan Luxeons have a median wavelength of 505nm; the peak absorption wavelength for rhodopsin is 498. Cyan light will _destroy_ rhodopsin rapidly, completely crippling your night vision. And since it takes about 30 minutes to replenish, you're completely out of the game if the light goes out. You'll actually get a few more lumens out of a green LuxI, and it will do far less damage to your night vision. Red-orange might be the best. At 617nm, it's effect on rhodopsin is negligible, and it's more visible than red (in addition to putting out more lumens at the same power).

I'll bet that guy really makes enemies quick, blinding all the other cyclists and killing their night vision.


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## iamerror (Dec 8, 2006)

I thought the headlamp was cool, I just am not quite sure how well the cyan would work. I had a couple questions about it if anyone can answer them. 

Could alkaline AA cells, rather than nimh, work for something like this? Would 4 white Luxeon Batwings work with this?


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## PeLu (Dec 13, 2006)

If it is only the luminous flux in Lumen you care about, every good ceiling burner carbide lamp should be able to give you more than 500lm....


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## chris_m (Dec 15, 2006)

Not even that impressive when you consider that my triple Cree gives out nearly 400 real lumens for 8W, and a similar one made with Q3s would give nearly 500 real white lumens.


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## AndrewL (Dec 15, 2006)

chris_m said:


> Not even that impressive when you consider that my triple Cree gives out nearly 400 real lumens for 8W, and a similar one made with Q3s would give nearly 500 real white lumens.


Is that out the front or at the LEDs? I always get a bit lost with the torch V bulb lumens and IIRC LED with optics don't loose the same as a bulb with a reflector

If I could solder (and had seen your tripple Cree first) I doubt I'd be using the bulbs I just bought


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## chris_m (Dec 15, 2006)

That's at the LEDs and based on keeping them cooler than I probably actually do. Given the way 500W is claimed though I didn't really see the point in scaling back to reality! The optics claim 90% efficiency, so should be ~350 lumens out the front.

Not like I'm the first with a triple Cree, but certainly in the vanguard. Will take some piccies tonight.


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## AndrewL (Dec 15, 2006)

so optics are a lot better then reflectors and lenses by the sound of it (assuming I'm getting 65% from my MR16 enclosed bulbs)


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## woodfluter (Dec 15, 2006)

Martini said:


> Yes, your eyes are very sensitive to cyan, but that's not really a good thing. The cyan Luxeons have a median wavelength of 505nm; the peak absorption wavelength for rhodopsin is 498. Cyan light will _destroy_ rhodopsin rapidly, completely crippling your night vision.



Good points, and I freely admit I don't know the answers, but I wonder if night vision isn't irrelevant here. Say you are cycling in traffic, with street lights. For me, my night vision is completely gone in that situation. I have very good and sensitive vision in near-dark conditions, but with any ambient light, forget about it! Perhaps the headlamp wavelength that provides the best step up in perception is the best. As I said, just don't know...

- Bill


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## Justintoxicated (Dec 15, 2006)

uhhh I must admit a cyan light would look brighter than a red one.

It's not about preserving your night vision, it's about your vision and its perception of different wavelengths of light. The Human eye is very sensative to this color so even a low brightness Cyan light can appear bright.

My next mod may be 4xcyan lux III's in a 2C. So if you don't own a cyan light you can't pretend to be an expert. 

Sure red is greater to preserve night vision (and would make a cool headlamp as well, but who needs night vision when you have a quad Cyan Headlamp pumping out decent lumens? This guy isn't going to be running into any trees.

For example my HID headlights destroy my night vision, but I don't see better when I drive with them off!

This mod would be best with Cree XE's ...Now to go dig through my old CPU heatsink box!


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## HenryE (Dec 15, 2006)

I think this just needs to be built... or some version thereof. 

Great idea.


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