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Headlamp flashlight technology takes a quantum leap! You can have it all: * Intense brightness * Lightweight * Long life * Low cost * Rechargeable * Unbreakable * Small * Waterproof * Unique shocking turquoise color

Race proven! I put the light to the ultimate test by competing in the Gold Rush 24-hour Adventure endurance race in the Sierra Nevada mountains of California. Many of the other competitors had $500 HID lamps from NiteRider, Light & Motion, etc, yet throughout the race nearly everyone that saw my light commented as to its extreme brightness or asked where they could get one. It was that much brighter than anything else.

Specs:
brightness: 500+ lumens / 7 million+ mcd @ 15 degree
weight: 120 gram headlamp + 60 gram electronics + 280 gram battery pack = 460 gram total
cost: $60 including batteries
lifetime: 3, 6, 12, 24 hours (4 brightness settings)
size: headlamp portion 5cm x 5cm x 2.5cm
rechargeable: Ni-MH or Lithium-Ion batteries (your choice)
unbreakable: LED technology

Tech:
- Cyan (or Green) high power/high efficiency LED's
- high-transmittance TIR lenses
- high-efficiency DC/DC step-down converter

None of this was possible just a couple years ago, but now it can be done easily with inexpensive components you assemble yourself!

i've got several other power-LED instructables too, check those out for other notes & ideas.

This article is brought to you by MonkeyLectric and the Monkey Light bike ilght.


Step 1: What's So Special Here?

Your eye! Remember back to biology class - your eye has "rods" and "cones". these are the sensing cells in your eye that detect images. the cones are your daylight & color vision, but they are less sensitive than the rods. Now the part you didn't learn in school:

(1) The rods are about 2.5 times more sensitive to light than the cones. That's why they are your night vision.

(2) The rods and the cones are not equally sensitive to all colors (wavelengths) of light. The wavelength of maximum sensitivity for your rods is 507nm, or blue-green. Why? Moonlight is more bluish than sunlight. The color of maximum sensitivity for your cones is 555nm green, about the color of plants. (more info)

To get the best possible vision at night, we'd like to build a lamp that puts out the most light at the 507nm that our rods are most sensitive to. This gets us the best vision at night for the least power used. If we had a white light instead, it would take much more power to get as much visibility.

Thanks to our friend the LED, this weird pure turquose light is possible! The latest LED technology is much more efficient than a standard light bulb to begin with, but using the special turquose color gives us even much better night vision than white, and is more efficient than even the fanciest HID lights.

Step 2: Ok, But Really What Is So Special Here?

well, basically there are a couple of things we do to get better efficiency and output than anything else you can buy/borrow/steal:

1) use cyan or green LED's. these will give 2.5x their rated lumen output using your night vision, because they are rated based on your day vision. (see http://hyperphysics.phy-astr.gsu.edu/hbase/vision/bright.html )

2) use the latest high-power LED's. new LED's such as the Luxeon's are rated about 50 lumens/watt for cyan and green (this is the day-vision rating). this is equal to the high-end HID lamps and at least twice as efficient as a halogen lamp. The Luxeon LED's used to be pricey, but now they are about $3 each.

3) use the latest optics custom-designed for the Luxeon LED's. several companies are now making low-cost lenses for LED's based on the TIR (total internal reflection) principal. These lenses do not have a reflective mirror, and achieve 85%-90% transmission. non-LED lamps lose much more of the light because some of the light shines backwards where it can't be used, and because mirror reflectors are less efficient. typical transmission for reflector-based systems is only 65%.

4) don't over-power the LED's. looking at the LED datasheet, we notice that the LED efficiency goes down somewhat with higher power: 45 lumens at 1W power, but only 80 lumens at 3W power. so we get the best efficiencies with less power. this indicates the importance of having a brightness-switch on the unit. in practice i have found the 1/2 power setting to be nearly as bright as the full power setting.

Step 3: What You Need

4 x Luxeon Star 1W Cyan (LXHL-ME1D or LXHL-ME1C) OR Green (LXHL-MM1C or LXHL-MM1D) - $3 each. (the circuit will work just fine with any color LED you want)

old CPU heatsink (around 5cm x 5cm x 1.5cm)
LED Dynamics Buckpuck (3021-D-I-1000 or 3021-D-E-1000) - $20
4 x L2Optics/Dialight OP-015 lens - $1 each
4 x L2Optics/Dialight OH-ES1-CL lens holder - $0.30 each
8-10 x AA NiMH rechargeables, or 3 x Lithium-ION rechargeables - $20 total for NiMH
2 small toggle switches (digikey 519PB) - $1.50 each
1 large toggle switch (digikey 514PB) - $2
flexible stranded wire (18ga to 22ga)
sheath for wire (eg: sheath of a 3/16" double-braid rope)
silicone or epoxy
thermal compound (also known as thermal grease or heatsink compound) - $5
plastic or fiberglass for heatsink mount
old headlamp headband

Where to get it:

old CPU heatsink - you will find these in any broken computer from 1995 onwards. in newer pc's the heatsink will be too large, but you can cut it with a hacksaw.

US/Canada:
the LED's, lenses, and buckpuck all come from future electronics also see here - the 2nd link is a direct search for the LED's and buckpucks. for the lenses, here is the direct search to find them.

Europe/World:
You can get the above LEDs, buckpuck & maybe lenses at farnell.com or rswww.com

- i recommend Luxeon 1W Stars, either Cyan or Green with either Lambertian or Batwing type. My testing shows that the 1W stars can be driven at 2W no problem with the heatsink, and they are much easier to work with than 3W stars because their backplate is insulated.

- Several different lenses are available for the lens mounts, so you can easily tailor the light to your needs. you can even change the lenses on the road in a minute or so. there are 5 degree, 15 degree, 25 degree and 5x25 degree lenses available, all are $1 each.

batteries are from http://www.batteriesamerica.com

switches from http://www.digikey.com (probably can find similar items from future electronics)

small quantity thermal compound. both computer and electronics stores have this. "Arctic Silver" is one of the common ones for computer use. Thermal adhesive is even better if you can find it (and it is pricey).
http://www.mouser.com (search for "thermal compound")
http://www.newegg.com (search for "thermal compound")
Digikey also has it, but only in $25 packs. CompUSA also will likely have it.

wire: 22ga is ideal here. you want something flexible that won't break after a few flexes. this can be surprisingly hard to find! radio-control hobby stores usually have something like this. at Home Depot you can get an 18/2 or 18/3 rubberized cable ("SJOOW") and split it open to get out the individual wires.

sheath: you want something to go over the wires and protect them. a good choice is a 3/16" or 1/4" double-braid rope (that means it has a core and a sheath). you pull out the core and have a sheath left. you can probably find this at Home Depot, if not try your local Marine store for yacht rope.


more information: the technical datasheets for each component:
Phillips Luxeon Star Led's: http://www.luxeon.com/pdfs/DS23.pdf
Led Dynamics Buckpuck: http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf
L2Optics/Dialight Lenses: http://www.l2optics.com/luxeon.aspx

Step 4: Solder the LED's Together

fit to heatsink. the led's are in a series-parallel configuration (2 led's in series, 2 pairs of that in parallel)

note that if you want to make a white headlamp, or any other color, the project will work exactly the same.

Step 5: Heatsink Goop

clean the heatsink first so that glue will stick to it later.

apply heatsink goo (heatsink compound aka thermal compound aka thermal grease) to bottom of LED's. you can also use thermal glue instead (and it is probably better if you do), but it is hard to find and a bit pricey.

stick LED's on the heatsink and wiggle slightly (but keeping the goop from getting all over since you need to have the glue stick later)

Step 6: Glue the LED's

the glue is all we are using to hold down the LED's. it seems tough and durable to me, but if you are worried the alternative is for you to drill 2 holes in the heatsink for each of the LED's (matching the cutouts in the star), and bolt them down with 4-40 size nylon machine screws. (or 3mm size). you can get nylon machine screws from www.mcmaster.com

1) do not get any glue on the LED lens. some glues (like silicone) you can get off the lens after it dries.

2) make sure the glue can handle 80-100 degrees celcius. (don't use hot-melt glue!). make sure it is waterproof (don't use superglue / cyanoacrylate)

3) i used silicone, but if i do it again i will try epoxy instead. the silicone does not flow by itself, so it is hard to get it to fully cover the LED (in order to have a submersible lamp). with epoxy you can dispense it with a syringe and accurately get it everywhere but the lens. smearing the silicone around is messy.

4) after pouring the glue, press the lens holders into place on top of the led's

Step 7: Attach Buttons to Buckpuck

hot-glue or silicone

the big switch is the master on-off

the small switches will control the brightness. you only need TWO small switches, three turned out to be overkill.

Step 8: Solder Brightness Resistors

refer to the schematic below. we'll build it using "point to point" wiring.

R1 = 680 ohm (blue gray brown)
R2 = 1200 ohm (brown red red)

these values worked for my buckpuck despite a somewhat misleading note in the datasheet, so test your resistor values before soldering.

these values give you FOUR overall power settings:
  • both switches off: full power
  • one switch on: 1/2 power
  • other switch on: 1/4 power
  • both switches on: 1/8 power



soldering note: these particular switches are made from fairly melty plastic so make sure you solder them rapidly. if you heat them for a long time they will melt inside and not switch properly. the best way to solder them without overheating is in 3 steps:

1) heat resistor lead and melt a small blob of solder to it ("tinning" it)
2) heat the switch lead and melt a small blob of solder to it also
3) now hold the resistor lead against the switch lead and melt the two solder blobs together, without needing to add any new solder.

this is good soldering practice in general anytime you are soldering something that is heat sensitive (such as the battery holders)

Step 9: Attach Headlamp

you will need an old headlamp mount (or you could make yourself one from a bungee-strap and plastic). you will have to figure the best way to attach your LED/heatsink to your headlamp since it depends on the details. for my headlamp, i cut two simple pieces of plastic (shown below)

Step 10: Strain Relief the Wiring

one of the keys to durable electronics is STRAIN RELIEF. any wire that gets bent or pulled will rapidly break if it does not have a good strain relief. there is a certain art to making a good strain relief!

first, i covered my entire wiring with a sheath from a 3/16" rope. if you've used very durable wire to begin with this may be overkill.

next, i made a strain relief where the wiring attaches to the headlamp, so that it won't get tangled or ripped when the lamp angle is changed, or the battery is dropped.

make an overhand knot in the wire, then glue it to the base plate. the knot gives much better grip to the sheath and the glue.

Step 11: Make the Battery Pack

the "Buckpuck" lets you use pretty much any battery pack. The buckpuck is just an efficient (90-95%) DC-to-DC step-down converter, so it will always output the correct voltage and current to the LED's no matter what the input voltage is. The LED's may need up to about 7V to run them, and you need to add 2V overhead for the Buckpuck - so any battery pack above 9V will work. 8 x NiMH cells will be 9.6V, 3 x lithium-ion cells will be 11.1V, and 10 x NiMH cells will be 12.0V. those are all good choices.

I used 8 x NiMH cells, AA size. These are 2700mAh cells, which yielded about 3 hours runtime at maximum power, and 24 hours runtime at minimum (1/8) power.

Step 12: Finish Wiring

connect the lamp and battery to the electronics

Step 13: Add Lenses and Test!

the lenses just press-fit into the lens holders

several different lenses are available for these mounts, so you can choose the lens angle you want.

don't stare directly into the light! it will blind you!
<p>As a motorist I am required to have my headlights adjusted so as not to blind an oncoming driver. I have several times had close calls to accidents caused my these superbright headlights worn on a cyclists head with the beam waving all over the place including directly into my eyes. These devices should be BANNED totally</p>
<p>I agree with you Colin.riddel. The lights on bicycles should be mounted on the bike and not waved around to annoy other drivers. Now-a-days most bike riders disobey the rules at night anyway and don't use lights of any kind. Also when is the last time you saw an adult cyclist with a bell on the handlebars? As a motorist you do require your headlights to be properly adjusted but when some drivers put huge tires on their pickups they forget that their headlights are now a foot higher and never get them adjusted. I think the police are missing this offence in every regard. Also most garages do not have the correct equipment for headlight alignment.</p>
<p>As far as the bell goes, it's not as effective as you may think. I had one, but haven't replaced it since it broke. It's not loud enough to get the attention of motorists (especially if they play music), and pedestrians are slow to recognize it, and confused when they do. I think the only time this helps is when riding with other cyclists. It's much more effective to use your voice. I personally say &quot;Passing on your _______&quot; when biking in passing period at school to let people know I am going around them.<br><br>I am guilty of riding without a light, because I am too lazy to replace mine after it broke (same incident as with the bell). 95 percent of my ride, though, is under streetlights, and I am always aware that motorists may not see me, and thus ride much more cautiously.</p>
<p>Funny, as a motorist I cross paths with cyclists all the time. Can't say I've ever noticed &quot;these superbright headlights worn on a cyclists head with the beam waving all over the place including directly into my eyes&quot;. As a cyclist I ride with 2 bar mounted lights and a head lamp, that way I can track ahead when I hit the trails. I've honestly only had one driver complain about the head lamp. He was in the oncoming lane and made a left that would have sent me to a hospital if I hadn't stopped. I looked directly at him with the headlamp. First he said the light was too bright, then he said he hadn't seen me before he turned. The thing is these lights are only blinding if you point it in someones face. Most cyclists are aware of this and keep it aimed at the road unless someone else isn't paying attention. Since you've had &quot;several close calls&quot; perhaps your driving and general lack of awareness are the issue? </p>
<p>Well wait a min a car driver almost has several close incidents with cyclists, (I'll assume he means nearly running then over / killing them) yea must be the headlamps, ofcourse it couldnt be his driving.</p>
Dear Mr TurdF1<br><br>I read you essay. You state &quot; Most cyclists are aware of this and keep it aimed at the road&quot;, most may very well do so but not all do. You however like a lot of cyclists seem to have to blame someone other than yourselves for anything that goes wrong
<p>I definitely understand and share your concern. And the same is true for some car LEDs. </p><p>Also, keep in mind;</p><p>1. Turn your high beams off; most bikers and pedestrians want to know you've seen them and likewise don't want to be blinded.</p><p>2. Slow down and give some space; some will use their light to get your attention if they think you have not spotted them.</p><p>3. Be considerate, keep in mind that you are not the soft target in a potential collision.</p>
<p>OK, I'm confused. If the light is &quot;waving all over the place&quot;, how is it blinding when the light isn't pointing directly at your eyes? </p><p>Ever bought a car and for weeks after the sale it seems like dozens of other drivers bought the same car? That's what is going on in your case.</p><p>Have you read any studies on the this? Is there actual data? Is data being supplied by &quot;THEY&quot; university? I'm not trying to be difficult but simply asking. There is a tendency for us to be knee jerk reactionary and call for banning or criminalize those things without ever asking &quot;is it me?&quot; first.</p><p>I've had night vision problems myself. Back in the 80's the only vehicle I used was a motorcycle. Of the 3 accidents I've had in total, 2 were night vision related. My last crash happened in 1997. Long story short, a $10 yellow visor has kept me from any night vision wrecks and put a flip down filter in my cars. </p><p>My last upgrade was putting a yellow decal on the top 3rd of my helmet visor only. This was done after putting a blue headlight on the bike and noticing some of the benefits using it went away with a filter. I just tilt my head if need be.</p>
<p>Frank: Would you ever think of putting a light on your motorcycle helmet and not using the ones on the bike. The ones on the bike do not wave around like a helmet light would.</p>
<p>That was actually my first thought. The bluer side of the spectrum has good visibility, but is also effective at blinding bystanders (or drivers, in your case). Couple that with how bright this thing is and it can become quite dangerous.</p><p>Perhaps it would better if only used out in the woods (or other secluded location) where there isn't going to be a passing motorist to blind. </p><p>On another note, I wonder how well a red headlamp would work with these specs. The color red is supposed to be very friendly on a person's night vision and is actually what pilots use in the cockpit when they have to read something at night. A white or blue flashlight could severely diminish a person's night vision capabilities for up to 30 minutes (bad combination for flying a plane).</p>
<p>Bear in mind that this is a 10 year old post, which means that it was made back in 2006. That in mind, this therefore is very impressive.</p>
I can't see where it says that this was posted 10 years ago o_O how do you know?
Just saw in the top right corner in about this Inscrutable, it says &quot;Posted: Nov 16, 2006&quot;. Don't know how I missed that until just now.
This is not &quot;night vision&quot; lol
<p>I made a few of these (3W LEDs are cheap where I live).</p><p>One is made from IR LEDs designed purely to blind IR CCTV cameras. Also works great blinding number plate CCTV cameras.</p>
<p>cool</p>
<p>I built this several years ago and it works great to this day. I use mine for camping and not out on a bicycle, but I too was getting complaints from my camp mates that it was too bright. So I added a potentiometer next to the power switch. Now I have a full range of brightness simply by turning the dial. Thanks for a great Instructable!</p>
<p>There are some really strange comments here : / I guess some people were thinking this would be best for cycling. I could see it being great just for working around the house or using at night camping.</p><p>Anyway, thanks for posting this great tutorial :)</p>
<p>My experience with headlights shows they conceal irregularities in the surface ahead. Mounted above the line of sight, the shadows you would normally see fall below your line of sight. The lower a light is mounted, the longer are the shadows projected from surface irregularities. I've hit some pretty nasty potholes when wearing a headlamp.</p>
<p> Most of the folks that come here are doing so because they enjoy making . Useful stuff adds to that .</p>
<p>I was going to ask, Why not red light for nighttime sports.....this article on lighting and backpacking explained to me well the pros and cons of red versus grey (blue green) and full spectrum lights and optimizing ones own night vision.</p><p><a href="https://backpackinglight.com/00202-2/" rel="nofollow">https://backpackinglight.com/00202-2/</a></p><p>And this is even better, argues dim white light is often better for seeing at night that red or cyan/bluegreen </p><p>http://stlplaces.com/night_vision_red_myth/</p>
<p>CraigL20 Both those companies make bikes for biking in the 500 dollar range in the present day. (check out the seca 2200, and if you needed to do a 24 hour race you'd need additional battery packs) I believe the bulk of light and Motion Lights are built in Monterey. Not sure if anyone uses HID anymore. I imagine it has its place.</p>
Leds are prrtty fun to play with. I made one with some bright leds and a lipo rc airplane battery.<br>I still have it and it still works although its kinda awkward to hold and not very pretty either.
<p>Seems I built this or one VERY similar from an article in Make magazine. I work in technical,theatre as a designer and stagehand and was excited to have a truly powerful headlight. After all was said and done, I was thoroughly disappointed. My Ray-O-Vac Highbeam headlight was brighter, more compact, and way cheaper. I ended up parting out the headlight and salvaging the parts. I didn't meter the two lights but put them side by side. the Ray-O-Vac was simply brighter.</p><p>I did learn a few important lessons though... but I wish I could have paid somewhat less to learn them though.</p>
<p>CraigL20 If you don't have something nice to say PLS don't down people publicly; that is rude; also I just now saw the notice in the corner be nice. Atleast he has tried, tell us of your great finding. God bless and may He place grace and mercy over you and all matters. Just curious is the 20 in your name for your age? Have a good one. </p>
<p>Great writeup, especially the info about rod and cone sensitivity. I came across an led &quot;miner's&quot; light at a bargain store a few years ago and noted the greenish tint, but thought these were just odd or &quot;one-off&quot; white leds. Nowhere near the same lumens output as your project though. :) Thanks!</p>
What issues would come from using a white light led, need something for hunting.
<p>Hi, I really like to make this project but can't find the same LED and LED drivers on europe shops, even the one you gave. </p><p>May be you could give some others refs in EUrope shops that can do fit as well..</p>
<p>Fantastic!! Thank you Dan sooo much. </p><p>Has anyone any experience with strobing the LED light to make it appear *even brighter*? </p><p>There's a discussion here: <a href="http://www.candlepowerforums.com/vb/showthread.php?188514-How-to-maximize-the-perceived-brightness-of-a-strobe" rel="nofollow">http://www.candlepowerforums.com/vb/showthread.php...</a> </p><p>If I read that right, it works out to 30Hz.... will the buckpuck/LED configuration support that? </p>
<p>One way that doesn't need any electrical skills is a LED head lamp take the cover off the bulb and put thin coloured paper or plastic over.</p>
<p>Great Instructable! I can't believe how old this is? Any updates as to its durability, bulb longevity, etc.?</p><p>Also, how could I make it to have a setting to flash/strobe as many bike lights do?</p>
<p>What is the best soldering iron or solder iron kit you all use for these tiny fuses or resistors? A link to a couple would be great! Amazon or anywhere is perfect. Is there like a better way than what I got? I have a big 60 watt or so and I use big roll of solder. Is there a gun maybe for tiny stuff or everyday type stuff. Thanks!</p>
<p>&quot;Moonlight is more bluish than sunlight.&quot; NO! Moonlight is nothing more than reflected sunlight = exactly the same color spectrum. It looks different simply because it is much dimmer and your eyes rods don't see color well.</p>
<p>moonlight is more bluish then sunlight due to the fact it indirectly comes in contact with the earth, there are greater chances for materials that obstruct its path to absorb the other colors of the spectrum, and the most resilient color of the spectrum is blue, hence why the sky is blue, and mountains and other objects in the distance appear more bluish because the other colors in the spectrum fade away before blue does</p>
<p>that would only be true the moon were a perfect reflector, which it isn't because you can see its surface features clearly. I don't know how accurate the blue statement is, but your statement isn't exactly accurate either.</p>
Agreed on color being an incomplete spectrum, after boucing off a giant hunk of stone, known as the moon. Since the moon rock I had the rare pleasure to view in person, encased in Lucite (Big thank you to science teacher, George Hutko!) I can say that it was a pale grey, and a timge greenish to me. <br>I have no idea what colors if any are lost in the reflecting, perhaps some across the spectrum, so at best a weakened version of sunlight.
Great project well detailed. Good job :)
<p>Exactly how many sticks of glue did you use?lol</p>
<p>Thanks for this ible and many links to explore. This looks definitely great. I want to adapt this to my car, use like some low-power rooftop lights. Thank you!</p>
From my experience with night orienteering, I found that a red light is worthless because green plants absorb the red light. Thus, they appear black like the rest of the night. A green light should reflect well from the leaves, making them easy to see. However, the green light may not reflect well from other color surfaces. White light has all the colors and will reflect off of any colored surface. I would like to see this headlamp made with white LEDs.
<p>Another factor to consider is how the light affects your eyes.<br>For reading maps &amp; instruments, red probably does the least to hamper your ability to see in low ambient light. The reason military &amp; aviation uses red lights inside vehicles is so that they can see outside with ambient light at night (especially military, where you don't want to illuminate the scene)<br>Night vision goggles have changed that somewhat because they amplify the ambient light.</p>
In many of the comments here, there is a reference to a &quot;buckpuck&quot;<br> <br> Please would someone tell me what a buckpuck is ?
A buckpuck is a LED driver, a component which delivers constant current needed by LEDs (especially high power LEDs).
<p>Thanks!</p>
<p>This is night illumination, not night vision.<br>But now I see why red light is used when you want to save your night vision.<br>Since this is in a wavelength you use to see at night, it would destroy you real night vision for a time.</p>
The design is flawed. That heatsink is not even half the size it needs to be for good LED&nbsp;lifespan and brightness.&nbsp; <br /> <br /> Literally, it is barely adequate for a single 3W&nbsp;LED.&nbsp; I&nbsp;have built plenty of LED&nbsp;lights for years and speak from a great deal of experience in light longevity and the effects of overheating.<br />
I want to build on this design but am unclear as to the size of a proper heatsink. I want to use the following:<br /> <ul id="ys_itemOptions"> <li>LED Type : Luxeon K2</li> <li># of LEDs : 4 (+$21.00)</li> <li>Color : Cyan</li> <li>Drive Current : 1000mA</li> <li>BuckPuck Options : Dimming w/ Pot.</li> <li>Power-Supply : 12vdc2.5a</li> </ul> How large of a Heat sink will I need?<br /> <br /> Thanks in advance.<br /> <br />
<p>I didn't realise how old this post was but it's still very relevant. There's an led heatsink calculator here:</p><p><a href="http://support.luxeonstar.com/customer/portal/articles/179490-how-do-i-determine-what-size-of-heat-sink-i-need-includes-heat-sink-calculator-" rel="nofollow">http://support.luxeonstar.com/customer/portal/arti...</a></p>
I intend to build this headlamp for night fishing and so I will have even lower airflow as I will be standing relatively stationary on a pier over the fishing location... So I would like some guidance on the required size of the heatsink you are suggesting? Would doubling the heatsink fin length (overall thickness dimension) of the heatsink serve the purpose..IOW I am trying to avoid making the length an width too big and clumsy on the headband.......ac-dc or Dan, Do either of you have a formula for calculating the size of heatsink required for safe - adequate cooling for the number of LED's used?
Have you designed bike lights? The ambient temperature is lower and airflow is higher. This could make up for the smaller heatsink than would normally be used.

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Bio: Dan Goldwater is a co-founder of Instructables. Currently he operates MonkeyLectric where he develops revolutionary bike lighting products.
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