Homemade medium bright trail running headlamp

[Jagge]

After swapping D bin P7 to my main headlamp I had one extra P to play with. So I decided to do a low power trail running headlamp/bike combi light. I don't always need full power of my current headlamp, I can do just fine with lower output if I don't go off trail too much. Some details:

- SSC P7
- 2.6 cm diamater OP reflector
- 2 mode 1A/150 mA driver. Led is under driven on purpose.
- 3x AAA battery pack
- output guestimates: high 320-350 lumens (looks about same as 20W halogen), low 60 lumens.
- burning time hight 2h15min, low 15h
- weight 173 gramms including battery pack and everything (same as Myo XP). I can use 3.7V li-ion batteries or 3/4 x AAAs, so weight can be reduced close to 120g
- head band is taken from old Silva M1
- lamp head is easily remomodes from the band and mounted to bike handlebar.

Some images:

(Just ignore those two strange toys Si and Emit cards, those ar just for size comparison for orienteering folks.)

Size comparison in last image, from bottom Petzl Tikka Plus, this new lamp and on top my 1000 lumens headlamp I still use on most of my runs and I race with.

 

[hopkins]

Hot stuff Jagge!!! Looking good.

 

[Jagge]

Thanks hopkins! But not really hot, only about body temperature...

Some details:

- Lamp head is made of DX drop in (sku 11836). I removed cree led and the driver to be used in an other project.
- C bin P7 star taken from a MTE flashlight. It had to be sanded down a bit. And open the reflector hole a bit too.
- kaidomain 1A/150ma AMC7135 driver, it had to be sanded down too to make it fit.
- 3 x sanyo 2700 AA nimh.
- Arctic alumina, some epoxy, wires, connectors etc.
- arc parts of the mount are part of a MTE flashight body. Black rubber clued on the arc of light head.
- Head band from an old Silva M2 headlamp I won from a race in Sweden long ago. I took battery holder box off and turned forehead part upside down to get lamp head high enough, far away from eyes. In low power head lamps you can have the emitter down on your forehead close to your eyes, but it's a bad idea for these more powerfull ones. You will blind yourself so easily if anything comes close to your eyes - like hands. Also rain, fog etc will effect much less if emitter is not so close to your eyes. Old well known head lamp design thing, but it seems to be ignored by most cheap headlamp brands.

I considered using original cree led for a while, but decided to use P7. Main reasons for not using original Cree led were:
- get Vf low enough to be able to use 3.6V 3xAA nimh or 3.7 li-ion battery pack with AMC7135 based driver.
- more output with same current (30% ?). And less heat, less need for hetsinking, less weight.
- bigger spot, better for running headlamp.
- I already had one extra P7.

So parts I used were not perfect, a bit too much sanding down. It would be nice to be find parts you could just throw pars in, some soldering and glue/epoxy.

I didn't add any heatsinking. After 40 min slow jogging yesterday at 7C the lamp head wasn't even hand warm. So I guess it should work just fine in warmer tempereatures too. With warmer temperatures or with more current you would have to but a some aluminium on it, or run faster to get more air flow.

---

This project was a side project of an other P7 headlamp project, details & beamshots here, homemade section of CPF.

 

[hopkins]

They all look good. Function is more important than the form of lights.
And your lucky getting lots of dark in the winter. Plenty of incentive to create. Here at only 37 N Lat winters nights are not so long.

 

[Offroad'Bent]

What a great little light! I think you could market those.

No Yellow SI card yet?

 

[Jagge]

Here is two clips of the other lamp in my normal use, jogging with it in a nearby park:
http://www.youtube.com/watch?v=56_NRiX2udQ
http://www.youtube.com/watch?v=nUiA_UwaDXE
I used the main light I linked above, not this low output one.

In the second video light is first off, then few seconds in middle and rest of the time in high mode.

 

[hopkins]

jagge looks like some fun running. Your forest is much more interesting than ours. Actually not forest here but grassland with fat oak trees clogging the ravines here east of san jose. City lights compete with the headlamp until crossing oak filled ravines.
I'd have at least 2 compasses for running your forest. Looks dense.

http://i37.tinypic.com/34dqxl4.jpg

 

[Jagge]

Well, after browsing O maps of Joe Grant Park east of Jan Jose where US Orienteering chaps were held some time ago I'd say I might get lost there in no time even with a packback full of compasses and three headlamps on my head....

 

[degarb]

I am intrigued. Been looking at that r2 drop in for two days. Thanks.

What drive levels were used during run video? How tight is the spot with that drop in, as it is hard to tell beam shape or angle from video?

Other questions are p7 color rendering and tint. Find a lens for the drop in? Where can plastic be bought to cover such a reflector? You should have photo'd a b4 r2 and after p7 beam shot. Did you test?

 

[Jagge]

I am intrigued. Been looking at that r2 drop in for two days. Thanks.

What drive levels were used during run video? How tight is the spot with that drop in, as it is hard to tell beam shape or angle from video?

Other questions are p7 color rendering and tint. Find a lens for the drop in? Where can plastic be bought to cover such a reflector? You should have photo'd a b4 r2 and after p7 beam shot. Did you test?

Ar first, the video was shot using the other headlamp I liked above. Most of the time I used 2.8A ~800 lumen mode. It the beginning ir was wriefly in med mode, it's 1A - same as hight of this med power light. You can see beam shots of that headlamp from the other thread (linke above).

But here is some comparison beamshots of this med power light.

Left Lupine Wilma @ low, 1W:

Left Lupine Wilma @ medimum mode, 9W (~600 lumens):

Left orienteerng halogen, 20W:

Left R2-drop in (image is in slightly larger scale):

R2 Drop in hotspot is pretty tight and intense, not ideal for trail running. There you can see a darker spot in the center. You can see it in natre too, but it's not that bad, it's just fine when you run with it. (I could take this photo becaus I ordered new dropins to be modded in similar way as a christmas presents. I'll just drive them a lot harder than 1A, the other reason for using P7 instead of a R2):

Daytime photo:

I can't run here with a tiny 80 lumen headlamp, I'll just break my bones. With few hundreds of lumens I can and it's lots of fun. And a perfect workout.

Edit: Lens is 26 mm diameter glass lens from KD. I had to order 10 pack.

 

[Offroad'Bent]

Hmm, enough lenses to make 9 more lights for your dear orienteering friends here on CPF?

 

[Jagge]

Those two lights I mentioned above are done. Slightly different setup here, but basicly the same. Same drop-in, but I used AMC7135 2.8A drivers this time. I took one chips off from the first and two from second lamp. So high modes should be slightly different: 2.1A and 2.45A. Low is 350ma in both, it is made using those removed AMC7135 chips (and diode from same kind of board). Main board is inside the lamp, low mode chip is inside epoxy close the 3 position switch & connector - there wasn't mych space left in the lamp head. In low mode current goes trough the main board too, this way I dont' need extra wire for low mode. D bin P7. Head band is made out of a cheap headlamp, I just removed the original lamp head and epoxied that arc (part of blue plastic pipe).

These lamps will be used with belt battery pack. But I made the wire short enoug for back of a head battery use. Belt pack will be used with extension cable.

I expect 8xAA Sanyo 2700 battery pack on high should give 600-700 lumens for 2-2.5 hours. And low ~120 lumens for 15 hours. The Weight of the light head + headband is 70g. wire to belt pack is about 35g and 5.4 mah 4.8V battery 235g. Total ~350g. Wirks well on table, test run tonight. I will not take/post a horror video of my run this time

Offroad'Bent - 6 lenses left... (one was lost in a diffuser experiment).

EDIt: These may not be as "medium bright" as the original one, but not the brightest around either - so not too far off topic I guess.

 

[lumafist]

Any "guesstimate" on output?

They do look great....!




I would need something like this for doggiewalks at night...
(that`s when I`m awake...)


Thanks for doing these DIY`s.....!

 

[dkvick]

Cool project Jagge :thumbsup:. What part of Sweden are you from by the way. I come from Linköping but have been living in Canada for the past 8 years. Anyway, I have been tinkering around with a similar project like yours but was going to re-use an old Silva reflector and retrofit it with a P7. Do you think that would work? Do you find that the flood is wide enough with the drop-in reflector? With the original reflector from Silva, the flood is crazy wide. I saw that Silva's new LED light uses 2x44 degrees and 1x 14 degree lenses. Do you need that much spread for orientering? I typically use my light for trail running and XC skiing. My preference is not to have too much of a spot since it's very annoying with a bright spot dancing in front of you when you are running so I have been reluctant to order one of the drop-ins or one of the cheap torches from DX to base the light on. What did you use as a lens cover for the drop in light?

 

[huskyrunnr]

This is very nice. I can only imagine a 700 lm LED headlamp so I would like to copy your design. You mention a lens. What is this lens and does it render the lamp weatherproof? Sorry for what may be an obvious point, but I am dilettante at this.

 

[Jagge]

First test runs are done. They ran slighty too hot even in 0 C temperature. It would have been fine for my own use, I'd just let the thermal protection limit the current, but because I am giving these away I added tiny heatsinks to not let heat limit output too much. Weight is now 71g with headband.

Flashlights usually have all too tight spot for trail running headlamp use. But with a large emitter as p7 you can't make tight spot with a small reflector. That's why I used these small ones instead of those designed for P7. You get wide beam/sidespill & large hotspot with these, at about similar to typical 20W orienteering halogens. I find it just fine for trail running. Some like more spotty beam for O, some not. I guess it's up to what you are used to. Youcan always use fiffuser to make it wider and softer with cost of less output of course.

ABout your Silva mod, depends what it is like. If it's 20W halogen with aluminium reflector, sure you can mod it and even use reclector as heatsink. If reflector is plastic, you need to be more carefull with heatsinking. If you mave one of those lesser silva lamps with plastic housing, you may get it difficult to get rid of the heat and it might get easier and better to use alu housing from the beginning - smaller, ligter, more durable, easier to make weatherproof etc. If I were you I'd order sku 3257 from dealextreme, just in case and as a comparison. it's similar or same reflector & base without emitter/driver, $3 so you don't loose much if you don't need it.

My lens is just plain glass, 27mm diameter. Just taped there. Weatetherproof enough, no problems in heavy rain so far. But I must make sure that taping is ok. I haven't submerged it, but I guess it would mind much short dive like tripping at a swamp. I am sure I will make experiment like that one day by accident.

Sweden? Don't know where that came from - but not far, Finland.

 

[dkvick]

Sorry Jagge, I just assumed you came from Sweden since you mentioned that you had won an orienteering event there. I have two orienteering lights, one Mila with all aluminum housing and reflector which was going to be my first victim for my light building habits, and one Silva which has aluminum reflector and front part of the housing, but has a plastic base where the old light bulbs were mounted. I would have to make an aluminum base for the emitter which will be relatively easy but i am not sure it's worth it. The Mila light should be quite easy since it has lots of aluminum for heat sinking. I was mainly concerned about the beam shape since the reflector was not made for LEDs. I will give it a shot since it will only be a few hours of work to convert it. I'll post some pictures later.

 

[Offroad'Bent]

Offroad'Bent - 6 lenses left... (one was lost in a diffuser experiment).

Any other surplus parts you'd be willing to sell to make up units, or just the lens so far?

 

[Jagge]

I can see I mentioned Sweden there. I was just wondering if you were able to locate country just by seeing the flora of the photo/video.

A friend of mine modded a Mila with P7. He got doughnut hole, but he slightly pressed reflector using bench vice and it dissappeared.

Surplus parts? Well, lenses, driver(s), R2 emitters, a reflector - actually I have parts for a lamp or two...but I also may make a lamp or two, like a R2 triple side shooter Mila mod...

 

[dkvick]

The photos reminded me of my the terrain back in the old country. Do you have any photos of your friends Mila mod? Any beam shots? Is he using just the housing as a heat sink or did he add fins or something to keep it cool? The most practical light light for me would actually be something like the one you show in this post. Something very light but bright enough so that you can run full tillt on moderately technical trails. I just modded a Tikka XP with a SSC P4. We will see if that is bright enough for easy trail running. It has a pretty narrow beam so it is not ideal and it is way to spread out with no reach with the diffuser on.