My first custom headlamp build

NYCaver

Newly Enlightened
Joined
Oct 27, 2009
Messages
49
I wanted to post this here since about 80% of the DIY knowledge I gained for this project came from CPF. Thanks CPF, this place is truly an awesome resource! Hopefully someone can learn from my experience and continue the cycle. Moving on...

So I got fed up with what was available on the market so I decided to make a winter project out of building a custom headlamp. The results I think at least give the high end commercial headlamps a run for their money, and in some ways one-ups them. The main goals with this project were in no special order:

- Rugged/Waterproof/Reliable
- Bright enough to be useful in supplementing strobes for cave photos, or even be used by itself for more confined shots. Also, able to dim to a reasonable level for hanging out/eating, etc.
- Options for both wide (right 2 leds), narrow (left), and combined beams (using the rotary switch)
- Neutral to warm tint LED's
- Repairable/upgradeable without too much trouble - able to be visually inspected while in a cave.
- Good efficiency and therefore good battery life. At least 24hrs, but preferably more run time on low.
- Cost around $100. This became unrealistic as I added features...ended up costing around $200 including the battery, some building supplies and many shipping charges.
- As compact as possible while meeting the above goals

Parts list:

  • 4x XP-E R2 LED's, 4D tint :twothumbs
  • TaskLED hipFlex driver - used instead of bFlex to be able to still have 700mA between two parallel strings on high when split.
  • Tenergy 11.1v 5200mAh li-ion pack, got a good deal on this. Going to switch to 3 cell pack for weight/size.
  • Grayhill 2 pole, 10 pos sealed adjustable rotary switch. Make-before-break style. Model 56SD36-01-2-AJS. Also a standard 1/8" hole rotary knob.
  • Mountain Switch brand momentary pushbutton switch with waterproof silicone cap
  • Turck picofast male right angle connector and female panel mount receptacle. Scew connector style.
  • 1X Carclo 10170 reflector, 1X Tina-XP-W combined for wide beam
  • 1X Ledil LXP real spot, 1X Tina-XP-D combined for narrow beam
  • 3"x2" 1/8" thick aluminum tubing, .875" cut
  • 1/8" thick aluminum plate, 1x 3"x2", and 1x 2.75"x1.75"
  • 1/4" x .5" aluminum bar, cut into .5" lengths
  • .1875" thick clear acrylic
  • Reell brand friction hinge. $2.50 on ebay.
  • Various screws, gasket material, neoprene bonded washers, etc...
I pretty much achieved my goals except for the cost and possibly the low brightness not being quite as dim as I'd like. Also, I would always like a less bulky headlamp, although it's not as bad as some I've seen. It seems to be very waterproof from my limited testing. It's pretty much a short section of 3"x2"x7/8" aluminum tubing with an aluminum plate on the back and thick acrylic on the front, all sandwiched together with 4 machine screws and some gaskets. The LED's are thermal epoxied on 1/4" thick squares of aluminum that are screwed on to the back plate with thermal paste. This allows the optics to reach the front of the housing while also allowing room for the pushbutton and rotary switch to enter from the side. This also makes future LED upgrades easier.

It puts out about 700-750 theoretical lumens on it's highest setting,(measured at 1.3 amps) and about 30 lumens on the lowest. Actual out the front lumens would measure lower I'm sure. On high the LED's are being driven over spec, but they're mounted on a good amount of aluminum so they should be fine considering high is just for short periods to check out larger rooms, pits, etc.

I haven't done real life testing of the runtime yet. According to conservative calculations with this battery it should get about 5 hours on high (~700 lumens, 1.3 A), 24 hours on medium (~180 lumens, .28 A), and 4 days on low (~30 lumens, .05 A). This is for 2 leds, the most common usage. When all 4 are running the overall lumens and effiency increase slightly since the current is split among 2 strings. It definitely heats up pretty well when on high, although it seemed to have been on high for a good chunk of time during the drive out to a cave the other day...enclosed in a backpack (whoops) and though it was hot, the thermal protection didn't seem to have kicked in.

The headlamp has some level of built in redundancy in the fact that it has 2 separate and independent strings of LED's. If one led goes, disabling a series string, (probably not the most likely failure mode, although it could happen) I can switch from wide to narrow beam, or vise versa to resolve the issue.

Tried it out in a cave for the first time the other day and was very pleased with how it worked. I don't think I'll really trust it fully till I have a few more lengthy trips with it. The big button is super easy to manipulate (too easy?) and the rotary switch is a great way to switch between beams. Overall, I couldn't be happier with how it turned out.
icon_biggrin.gif
Glad I didn't have to shell out $600 for a high end commercial headlamp. I might be hooked on this whole DIY thing!

EDIT: I'll see about getting some beam shots posted some time soon.

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Last edited:

uk_caver

Flashlight Enthusiast
Joined
Feb 9, 2007
Messages
1,394
Location
Central UK
Nice!

With your power levels, is that high/med/low which you can apply to either one string, or the other, or both, depending on the situation?
 

DaFABRICATA

Flashlight Enthusiast
Joined
Jan 10, 2007
Messages
3,946
Location
Michigan
Sweet build!:twothumbs:cool:

It's cool that your hard work paid off and it does what you designed it to do! The best part is that you enjoy it so much!:naughty:
Lookin forward to those beamshots and updates. Maybe you could take some while in the places you explore to show it in action?..:popcorn:
I've always wanted to build a more complicated headlamp like that.
I started one, but never finished....thanks for the motivation!
 

NYCaver

Newly Enlightened
Joined
Oct 27, 2009
Messages
49
Nice!

With your power levels, is that high/med/low which you can apply to either one string, or the other, or both, depending on the situation?

Yep, basically it's 2s, 2s, or 2s2p which splits the current of the various levels.

Sweet build!

It's cool that your hard work paid off and it does what you designed it to do! The best part is that you enjoy it so much!
Lookin forward to those beamshots and updates. Maybe you could take some while in the places you explore to show it in action?..
I've always wanted to build a more complicated headlamp like that.
I started one, but never finished....thanks for the motivation!

Thanks man! You're right. The best part is when you realize it's actually working the way you intended, and that it's actually very good at what it's supposed to do.

I'll try to get some basic beamshots tonight, and maybe some action shots next weekend while I'm underground.

Finish that project! You'll be glad you did. :thumbsup:
 

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