# The hedgehog - quad luxeon camping lantern



## evan9162 (Aug 16, 2006)

Now, for my latest creation....

BEHOLD!











(showing the carrying handle)

This is a fully adjustable, quad-luxeon camping lantern. Output can be adjusted from a dull glow to spot-inducing brightness, or anything inbetween.
It runs off 6-D batteries.

It is constructed from aluminium. The lower body is a 4.5" piece of 4" aluminium square tube, 1/8" thick. The top part of the body is a giant heat sink to keep the luxeons cool. It's probably massive overkill (more info about the heatsink below) - but IMO, you can never keep your luxeons too cool.

The luxeon stars sit on a pedistal that's attached to the bottom side of the heat sink. The pedistal is a 1" square piece of aluminium bar stock, 2.5" long. Here's a closeup of the luxeons:





There are two strings in parallel of two luxeons in series (series-parallel setup). 

Here's where this thing gets its name - the heat sink:






It is a round pin-fin design, which works really well for any direction airflow, or still air. It has 48 pins, in a 7x7 grid - there is no pin in the centermost spot due to the pedistal attaching to the plate at that point on the underside

The heat sink starts out with a base plate of 3/8" aluminium, 4" square. Into that, I drilled 48 holes and tapped all of them. The pins are 1/4" aluminium, 2.25" long. They are threaded for 3/8" and screwed tightly into the base plate using some thermal compound on the threads to aid heat transfer. Overall, it took me about 12 hours of drilling, tapping, cutting, and threading to get this built.

The heat sink performs very well. I measured 1.5C/W in still air, 0.5C/W with a weak 80mm fan (~20cfm) and 0.3C/W with a huge 5" 135CFM fan. Given the paltry 7W (max) of heat this thing needs to dissipate, these luxeons will stay cool as a cucumber.

Here's the underside with the bottom cover removed. 





There's an internal bulkhead that separates the battery compartment from the electronics. The 6D cells sit in a 2x3 battery holder. Pay no attention to the mix of Ray-O-Vac alkalines (blue/silver) and Sanyo NiCD cells (green) - I couldn't dig up 6 identical D cells...







You can't really see it, but the regulator circuit is stuffed in here. I'm using an LDO op-amp controlled linear regulator. Using the pot, the total current can be adjusted from 20mA up to over 1A. The current is split between the two luxeon series strings, so each luxeon gets from 10mA-500mA.

Some "beamshots" (not much of a beam since this is an area light)

20mA (lowest setting)






200mA 






500mA 






800mA






1A+ (highest setting)







Approx. REGULATED runtimes:

```
20mA	900 hrs (37.5 days)
100mA	150 hrs (6.25 days)
200mA	 70 hrs (2.9 days)
300mA	 45 hrs	(1.9 days)
400mA	 30 hrs (1.2 days)
500mA	 21 hrs
600mA	 15 hrs
700mA	 12 hrs
800mA	  9 hrs
900mA	  8 hrs
1000mA	  6 hrs
```

The 20mA level is perfectly acceptable for reading or finding your way around in the dark - and you get nearly 40 days of continuous light!


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## greg_in_canada (Aug 16, 2006)

That is awesome. 

Dropping from 1000mA to 500mA increases the run-time by a factor of 3.5. Is that due to the cells loading down at 1A and becoming inefficient?

Greg


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## greg_in_canada (Aug 16, 2006)

Isn't the heat load 14 watts? I.E. 3.5V x 1.0A x 4 Luxeons. Or is the 1A the battery draw and the current per LED is 500mA?

Greg


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## eebowler (Aug 16, 2006)

LMAO evan. Is it waterproof?


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## NickBose (Aug 16, 2006)

Holy cow! I wish there was something like this in the store.
Are those spikes the only solution for heat dissipation? They're a bit bulky to appear on a commercial product.


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## Ra (Aug 16, 2006)

Ist an increddible looking monster.. one thing tho... 

Shouldn't it be nice to make some sort of milk-glass around the led's.. Otherwise sitting around this lamp will not be very comfortable with so much light comming from those tiny led-junctions, even at low power !!

And.. yes, the heatsink is massive overkill: That is one of the many good things on this light !

Ra.


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## jar3ds (Aug 16, 2006)

very nice! 

I was thinking of making something similar to this... a little smaller.... However, I would want it to be waterproof and I would use like 8 LED's  and diffuse the light...

very inspiring!


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## Ra (Aug 16, 2006)

Oh.. I forgot..

If you are a romantic you can use wharm white luxeons and even electronicly introduce some flikkering !?!

its just brainstorming about this....

Ra.


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## Dr_Joe (Aug 16, 2006)

Boy that's alot of work  48 hand drilled and tapped holes and 48 hand cut and threaded rods ! This could be a shop class project for a whole semester :lolsign: 

It certainly is unique


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## KingSmono (Aug 16, 2006)

Awesome looking lantern!! Nice job.

-Allen




Ra said:


> Shouldn't it be nice to make some sort of milk-glass around the led's.. Otherwise sitting around this lamp will not be very comfortable with so much light comming from those tiny led-junctions, even at low power !!



No more uncomfortable than one of those Coleman Gas Lanterns... those suckers leave spots in your eyes for days!


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## zespectre (Aug 16, 2006)

Next project... the same thing in a waterproof sphere and you can call it the Sea Urchin!!!

LOL

Love it though, great job!


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## Ra (Aug 16, 2006)

KingSmono said:


> No more uncomfortable than one of those Coleman Gas Lanterns... those suckers leave spots in your eyes for days!



Beleve me... Those Colemans are much nicer to your eyes than this luxeon lantern: Lower colortemperature and much lower surface brightness !!

So if Colemans hurt your eyes like you said, imagine what the above can do..


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## iNDiGLo (Aug 16, 2006)

I want it. How much?  :goodjob:


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## Tritium (Aug 16, 2006)

FrankenLantern to be for sure. :goodjob: 


Thurmond


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## Illum (Aug 16, 2006)

Ra said:


> And.. yes, the heatsink is massive overkill: That is one of the many good things on this light !
> 
> Ra.



evan probably made the heat sink to prevent people from sitting on it...:laughing:


This is awesome!, now theres a true hurricane lantern.
:goodjob: Whens the date for production?:rock:

Is that acrylic or plexiglass? you could try and sand the surface so the light evens out, then hang it on a tree and your camp would be bright as day...:naughty:
suggestions: try making hinged covers with reflective bottom sides so you have area lighting when hung up on a post.


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## evan9162 (Aug 16, 2006)

greg_in_canada said:


> That is awesome.
> 
> Dropping from 1000mA to 500mA increases the run-time by a factor of 3.5. Is that due to the cells loading down at 1A and becoming inefficient?
> 
> Greg





> Isn't the heat load 14 watts? I.E. 3.5V x 1.0A x 4 Luxeons. Or is the 1A the battery draw and the current per LED is 500mA?



1) Yes - alkaline cells aren't able to deliver their full capacity at high loads - those calculations are based on using alkalines. When using rechargables, the runtime relationship is almost perfectly linear with respect to current draw

2) the 1A is split between two strings of two in series, so each LED only gets 500mA - so the heat load is around 6.5W or so.


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## evan9162 (Aug 16, 2006)

eebowler said:


> LMAO evan. Is it waterproof?



I could make it fairly water resistant, but the switch and pot would be the main water infiltration points.


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## evan9162 (Aug 16, 2006)

NickBose said:


> Holy cow! I wish there was something like this in the store.
> Are those spikes the only solution for heat dissipation? They're a bit bulky to appear on a commercial product.



This actually started out with me wanting to build a massive round pin-fin heat sink just to see how good of a sink I could build, then I decided I'd just use it on this lantern project I've been thinking of since I'd have no other use for it afterwords.

The amount of power dissipation could probably be handled with a flat plate with short (1/2") fins. So this is really unnecessary from the "what's really needed" department. 

I like how this thing looks like a prop from an old sci-fi movie


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## evan9162 (Aug 16, 2006)

Ra said:


> Ist an increddible looking monster.. one thing tho...
> 
> Shouldn't it be nice to make some sort of milk-glass around the led's.. Otherwise sitting around this lamp will not be very comfortable with so much light comming from those tiny led-junctions, even at low power !!
> 
> ...



The clear parts are 1/8" acrylic - I'm planning on frosting the inside (light sanding, perhaps) when I get around to it, or if it bugs me too much - I didn't do this right away since I wanted to make sure the lantern was going to be bright enough for general use - no worries there.


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## chimo (Aug 16, 2006)

Great job on this! I like the "industrial" look.

Paul


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## ACMarina (Aug 16, 2006)

Group Buy!! GROUP BUY!!


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## jar3ds (Aug 16, 2006)

you've inspired me to make a similar latern w/ 18650's


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## mosport (Aug 16, 2006)

Niiiice work Evan! I like projects that showcase fabrication techniques, the time invested into the heatsink is incredible and has paid off.

Does this lantern have a nickname?

:thumbsup:


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## georges80 (Aug 16, 2006)

NICE fabrication work - but... personally I HATE lanterns that shine light out of all sides and in the face. That's why I built my 3 Luxeon based camping light with locline and reflectors (60 degree beam) so I could a) hang it from some height and b) direct the light where it was needed rather that in peoples' faces.

I posted these pics a long time ago - still my favourite camping light and it is dimmable from 20mA to 1A (for when you really need some light).












george.


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## Illum (Aug 16, 2006)

to lower the profile of the "hedge", tapp some holes at the top of the emitter's mounting post, wire a CPU fan inside the aluminum square bar to circulate the air up and under the hedges...
maybe use a rechargeable battery pack [lead acid or lithium ion] since the fan might draw more amps from an alkaline set of batteries than you bargained for...just suggestions

*
:rock::rock:~What a masterpiece this is!~:rock::rock:

*Im surprised I never thought of such design, so deceptively simple.
Thats more heavy duty than the plastic "polymer" camp lanterns I've seen


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## Krit (Aug 17, 2006)

Nice Works........


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## Robban (Aug 17, 2006)

It reminds me of this heatsink from Swiftech that was popular a few years ago. The MCX462:


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## evan9162 (Aug 17, 2006)

Pin fin heatsinks like that were the inspiration for building the heat sink in the first place. Note that the swiftech unit has closely spaced pins, since it was intended for forced air cooling. My heatsink was designed for still air/very low airflow, so widely spaced pins is necessary to allow convection to move air through the sink or allow very slow airspeeds to penetrate and flow over all of the pins.

They also machined spiral grooves in the pins to increase pin surface area - again a design element intended for forced air applications. I played around with putting shallow threads in the pins, but figured that the natural air cooling that this would be using most of the time would not benefit from the threads - in fact, the threads would probably hamper heat sink performance by creating pockets of stagnant air that would not allow convection air flow across the surface.


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## evan9162 (Aug 17, 2006)

A cookie to anyone that can guess where I got the carrying handle...


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## chimo (Aug 17, 2006)

evan9162 said:


> A cookie to anyone that can guess where I got the carrying handle...



Paint Can?


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## nemul (Aug 17, 2006)

thats really cool!


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## bombelman (Aug 17, 2006)

:twothumbs :goodjob:


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## Robban (Aug 17, 2006)

evan9162 said:


> Pin fin heatsinks like that were the inspiration for building the heat sink in the first place. Note that the swiftech unit has closely spaced pins, since it was intended for forced air cooling. My heatsink was designed for still air/very low airflow, so widely spaced pins is necessary to allow convection to move air through the sink or allow very slow airspeeds to penetrate and flow over all of the pins.
> 
> They also machined spiral grooves in the pins to increase pin surface area - again a design element intended for forced air applications. I played around with putting shallow threads in the pins, but figured that the natural air cooling that this would be using most of the time would not benefit from the threads - in fact, the threads would probably hamper heat sink performance by creating pockets of stagnant air that would not allow convection air flow across the surface.


Yup, it's made for CPU's so it has the benefit of having constant airflow from a fan to get things moving. The only reason I posted the picture was because that HSF immediately popped up in my head and I reverted back to my overclocking and cooling days with computers. Nostalgia trip 

Also, I think I've figured out the REAL reason you put those pointy things there right above a heat source... you wanna cook your hotdogs on em don't ya!


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## evan9162 (Aug 17, 2006)

chimo said:


> Paint Can?



Nope - it came from a much stranger place than that.


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## Cypher (Aug 17, 2006)

The handle looks like one of the legs off of one of those little propane bottle powered grills.


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## evan9162 (Aug 17, 2006)

Cypher said:


> The handle looks like one of the legs off of one of those little propane bottle powered grills.



Getting warmer.

I'll spare everyone a zillion guesses.

It's part of the undwire frame / handle from an aluminium foil turkey roasting pan. My wife didn't use it and was about to throw it away - there are two pieces like the handle that go under either side of the pan - I simply cut one out, bent two little prongs inwards and that's it - no shaping required!

Who knew that the grocery store had flashlight parts....


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## lukus (Aug 18, 2006)

Is it a wire clip for holding components in a rack? (doh! that's what I get for walking off in the middle of a post.)

If you can shrink it down to half the size and weight, I'm in for the group buy.


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## NickBose (Aug 21, 2006)

How bright is your hedgehog comparing to this Coleman


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## evan9162 (Aug 21, 2006)

Very difficult to tell. The coleman site does not give any information about brightness. They say it has a 15W CF bulb, but that does not mean that it's driven at full power.

We can extrapolate a bit given the quoted runtime and characteristics of D cells.

On high, the runtime is quoted at 14 hrs. To get 14hrs of service from a D cell requires you draw only 600mA from it. With 8 D cells, 600mA gives 7.2W. So on high, the lamp is only being driven at 1/2 power. I have no idea how efficient CF bulbs are at partial power, but if we given them 50 lumens/watt, then they're outputting about 350 lumens. On low, they quote 24 hrs of runtime, which is about 400mA, or 4.8W - giving maybe 250 lumens. Again, I don't know how well CF bulbs dim in terms of efficiency, so these are just guesses. I would imagine that the numbers are actually lower due to dimming and ballast losses.

The hedgehog puts out about 200 lumens on its highest setting, down to maybe 10 at its lowest setting.

The coleman lamp is much larger, at 6" x 6" x 12", vs 4" x 4" x 10" for the hedgehog - and it uses 8 D cells, vs 6.


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## Pixel (Aug 21, 2006)

I still see plently of room for 4 red-orange Luxeons, 4 cyan, 4 warm, 4 green and 4 royal blue. These color modes can be cycled , strobed, etc., for a true psichedelic camping. No bear could resist.


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## andrewwynn (Aug 27, 2006)

GREAT mod i love it!

-awr


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## Ken_McE (Aug 27, 2006)

evan9162 said:


> The amount of power dissipation could probably be handled with a flat plate with short (1/2") fins. So this is really unnecessary from the "what's really needed" department.



Darn, and here I was thinking those slots were so I could use it to make toast 8-( Your lantern is magnificent. Simply magnificent!


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## IsaacHayes (Aug 28, 2006)

Hmm you could water proof the controls by "boxing" them and have a tupperware lid or flap that you take off to turn it on/off and adjust the brightness. That would be cool, and put the whole thing in the pool or in the water from a boat to see fish/etc at night!

I'd say frosting would be cool, but then when it's off you wouldn't see the cool pedistal and then the wires going down. It looks like some NASA thing or something! 

I think I'll make a lantern with spare luxeons (pulls, including clones etc) after all but perhaps make it like the coleman, with 180* spread.

You just need a strobe mode with 1 amp to each luxeon and that'd be AWESOME!! 

EDIT: yeah r/o or true cyan luxeons would be nifty!


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## evan9162 (Aug 28, 2006)

Strobe...ugh...

I truly despise the flashing mode on my River Rock Nichia lantern. It would have been much more useful to have a high and low mode. I'm tempted to build my own circuit board for that light, and make it fully dimmable like this light.

I'd always planned on frosting this thing. I can deal with not seeing the pedistal for a less hash light source, now that i know that this thing is plenty bright.


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## Illum (Aug 29, 2006)

some reason I feel you should patent it and disclose it to the department of transportation about "portable Programmable traffic lights" during the hurricane season...Ive seen too many four way jams resulting from the traffic light power supply going


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## fleshlite (Aug 29, 2006)

Milk can

chris


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## NickBose (Aug 30, 2006)

What about
- frosting the acrylic 
- changing the power source into an SLA 18AH
- changing the LEDs into higher power LEDs
like this 10w LEDs 






or this 20w LEDs 





and it will become one hell of a hedgehog! Maybe you should ring Guinness then.


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## evan9162 (Aug 30, 2006)

It's already plenty bright (I doubt I'll use the highest setting very often)
It already runs long enough on alkalines or NiCDs, and an 18Ah SLA won't fit in the body.
I'll eventually get around to frosting the acrylic once I finish this massive carpentry project for my wife's preschool classroom.


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## evan9162 (Sep 6, 2006)

Now in a frosty version:











I took some 320 grit sandpaper to the inside surface of the acrylic. It's now a smooth frosty finish that eliminates the eye glare of the bare luxeons. Even if it is dimmer, it's still plenty bright.


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## IsaacHayes (Sep 7, 2006)

Looks better frosted lit up, un lit up, clear is better. But it's built to be used, not admired right?  Strobe would be fun, for some people at least. Actually, throb mode would be cooler and less harsh to the eyes. And I guess in emergencies. Perhaps r/o luxIII for the strobe allong with some true cyan, no wait, that might look too much like cop lights!! hehe.

Have you put it to actual use anywhere yet? I will eventullay build some sort of lantern, probably DD though, to just suck down spare batteries until they leak (alkalines). It will use scrap pulled luxeons/clones and be max brightness until the batts give out or finally die out. Lots of luxeons in parallel, so even if the batts can't do full power, then effenciency is up since low power to a led improves lm/watt and since I have a bunch of leds for area lighting, then it's still decently bright. I'll probably build it to accept d's, c's and AA's. Might even put a switch with a slew of 5mm red leds on the side or something... A regulation circuit would be nice, but I want this thing to be dead cheap since it will be spare parts!! I think the HS's will be frome salvaged 486, K6, and p4 HS's laying around!


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## jar3ds (Sep 7, 2006)

very nice!


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## evan9162 (Sep 7, 2006)

IsaacHayes said:


> Have you put it to actual use anywhere yet?



Yeah, I've walked around the house at night with it - nicely lights up the area around you, without destryoing your night vision. Using a high powered light shining at the ground would certianly cause spot blindness and loss of peripheral vision. 

I find that it provides plenty of light for even a large room on only 1/2 brightness or so. 

Haven't had to use it long term, power around here is just too darn reliable


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## IsaacHayes (Sep 7, 2006)

cool. I know what you mean about blinding yourself at night with a light. One time outside I shined my tri-lux and also once my u-bin mag mods at the ground and was seeing spots for a long time!!!

Sounds like you need to take it camping!!


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## Illum (Mar 8, 2007)

any plans for CREEmation?


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## evan9162 (Mar 8, 2007)

Nope, it's plenty bright right now. Plus, the cree's have a narrower emission pattern, changing the light output (i want it as wide as possible).

I've used this in the last couple weeks while working up in my attic. The handle makes it indespensible, I just hang it on a screw in one of the rafters. The 360-degree output lets me see everything regardless of the light's orientation. I've only had it turned up to 1/2 brightness, which is plenty of light, so more light really isn't needed from this thing


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## itch808 (Mar 8, 2007)

Nice, beats the hell out of a propane lantern!


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## Meduza (Mar 8, 2007)

If you swap to Seoul P4 it wont change the radiation pattern, it would just be more effecient


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