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Instructables headlamp

PostPosted: Jul 7, 2007 10:59 am
by RNagot
New guy here, just wondering if anyone has seen this, looks like a neat and bright setup.

http://www.instructables.com/id/E2K9BN5EDKEUBYRD9V/


here he has circuits for high power led's

http://www.instructables.com/id/ERVLPDU5XVEWOF31U3/

any thoughts?

Ross

PostPosted: Jul 7, 2007 11:16 am
by Vader
Looks like alot of work and to good to be true.

I would like to hear from some cavers that have tried it.

PostPosted: Jul 7, 2007 7:00 pm
by FiddleCaver
He's not exaggerating on the brightness of that setup. I've built several similar prototypes using 3 LEDs of highter efficiency that were of similar brightness. The only drawback I can see to this setup is the weight of batteries. 8 AAs is gonna weigh quite a bit on your head. I personally would use some 18650 li-ion cells. 4 of those in series and you've got 14.4 Volts, and a lot more Amp-Hours.

PostPosted: Jul 8, 2007 9:54 am
by Ralph E. Powers
Well dunno if this is really that great or not, if you look at step one you'll read that he's talking about using a blueish turquoise colored light to better "enhance the night vision"...
I'm like... well uhh, okay but it's not going to be the same when caving. Mebbe outside like hiking from the cave entrance after a long trip, back to the car/truck(s) and all of that... sure but...

So reviews by cavers while using the light IN caves is what I'll be looking for.

FiddleCaver, I still use a Petzl MegaBelt on my helmet and use 3 C's cells so the weight of 8 AA's isn't going to be that big of a deal ... at least not for me.
:tonguecheek:

PostPosted: Jul 8, 2007 10:28 am
by Jeff Bartlett
i just read through the instrutions for this and he stresses that you can use a white LED or any color you like. so someone could definitely try this with the intent of having a regular white light.

however, i don't know how applicable this would be for caving, no? it seems most people using, say, the Apex don't use it on "high" very much for the sake of blinding themselves and their fellow caves. i'd hate to turn around and catch an eyeful of THIS thing.

PostPosted: Jul 8, 2007 6:06 pm
by FiddleCaver
I agree that the blue lights, would make things look funky. There are white LEDs that are more efficient now anyway.

Ralph, you could trade those C cells for some of the li-ions I mentioned, and have twice the runtime and half the weight...

PostPosted: Jul 8, 2007 8:58 pm
by Jeff Bartlett
i'd also worry a bit about how waterproof/shockproof it is without a real housing for the lamp portion.

PostPosted: Jul 8, 2007 9:59 pm
by Realms
It needs a housing. Wouldn't last one trip with me like that.
I use a 3led setup that is powered by 16AAs located in a converted petzl carbide generator. Soon to switch the leds over to the SSC P4's that crank out 240 lumens each giving me a total of 720 lumens.

PostPosted: Jul 8, 2007 10:52 pm
by Jeff Bartlett
Realms wrote:It needs a housing. Wouldn't last one trip with me like that.
I use a 3led setup that is powered by 16AAs located in a converted petzl carbide generator. Soon to switch the leds over to the SSC P4's that crank out 240 lumens each giving me a total of 720 lumens.


the headlamp on your helmet in the avatar photo, i presume. you custom built that? can we get some better pics of that setup?

PostPosted: Jul 9, 2007 5:21 am
by potholer
SSC P4s are certainly excellent little things - even at low-ish power, they still put out a serious amount of light, and are a big step up from Luxeons. There are suggestions they can go blue at higher power levels, but I don't drive mine that hard.

The comparable Cree XR-Es are also excellent, and do look a bit cooler in 'naked LED' configurations for flood beams, but can be quite a pain to solder connections to once they've been thermal-epoxied onto a heatsink.

Regarding the constant-current circuits linked to in the first post, they may be fine for situations where there is ample drive voltage, but the transistor-based design does end up consuming a fair bit of voltage (~0.6V) across the current-sense resistor.
An op-amp-based design isn't necessarily much different in cost or size, but can have much lower dropout voltage, and so can work well for situations like driving single white LEDs from 3xNiMH, 3xAlkaline or 1x Lithium cell.

PostPosted: Jul 9, 2007 7:58 am
by RNagot
thanks for all the input.

Realms i'd love to see a build up of your light

PostPosted: Jul 9, 2007 11:06 am
by Jeff Bartlett
what are we looking at cost-wise for the Cree XR-E or SSC P4 versus a 3W Luxeon?

PostPosted: Jul 9, 2007 11:27 am
by potholer
Buying either U-bin SSCs or P4-bin XR-Es in 10-up quantities, I've been paying $8-$10 each.

PostPosted: Jul 9, 2007 2:17 pm
by Realms
heres a pic.

Image

PostPosted: Jul 9, 2007 7:41 pm
by FiddleCaver
Check out Dealextreme.com for some good deals on Cree and SSC LEDS, optics, batteries, and cheap regulators. They ship from Hong Kong so it takes a couple of weeks to get things from them.