How to do a one-mode AAA case mod/replacement with goal being ultra light weight

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carbone
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How to do a one-mode AAA case mod/replacement with goal being ultra light weight

Newbie here. I would like to do a bare bones AAA light made from the innards of an existing one-mode light.

The goal is ultra light weight, at the expense of shock/water/dust/etc. protection. I do want at least a reflector and probably a lens.

So far my idea is to use a large diameter straw as the case, have a wire of some sort running from the end to the bulb end, and possibly even omit the switch, worst case scenario just jamming the wire against the battery when light is needed.

I realize this sounds sort of bonkers. And I understand it won’t be blast proof, or water proof, or very durable at all. But the idea is sort of a fun challenge to myself to see how light it can get and still be a nice little neat or almost-neat package. Ultimately it will be carried in a small EDC kit (EDIT: as a backup, not a main EDC flashlight). Existing tiny lights don’t fill the bill because I want both AAA and absurd lightness.

I picked up a Coast G10 with this project in mind but it doesn’t seem to want to open. If anyone knows how to open it, I’ll start there. If not, I’m looking for suggestions as to which flashlight might be easy to work with (and maybe a worthy sacrifice, not something I’d want to keep intact) for the purpose I’ve described. I’m set on AAA because of the ease of buying them almost anywhere.

Not set on having a lot of lumens… anywhere from 20 to 100… higher is better, but on the low end of that is fine.

My question for the forum is: what are some good single mode lights to start with, assuming I don’t want to build everything myself, but prefer to take something that is working and just repurpose the insides (the “pill” I suppose it is called?)

Edit: And by the way, super excited to find this forum! Hoping to do or get in on some other projects here in the future!

Edited by: carbone on 10/10/2017 - 13:05
skinny_tie
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This doesn’t answer your question, but have you considered using a 10mm LED?

Sure, the output would be at the low end of what you’re looking for, and it would probably be more complex, and maybe even more expensive once you bought a driver, but it would be bonkers.

1 × 10mm drinking straw – $0.05
http://www.ebay.com.au/itm/33x-Bubble-Boba-Tea-Fat-Drinking-Straws-Party...

1 × 10mm white LED – $0.13
http://www.ebay.com.au/itm/10-pcs-10-mm-white-light-emitting-diode-LED-W...

1 x DC-DC Step Up/Down Converter 1.8V-5V to 3.3V* – $1.24
http://www.ebay.com.au/itm/DC-DC-Step-Down-Step-Up-Converter-1-8V-5V-to-...

* I know that driver’s not quite right, but I’m sure there’s something out there.
carbone
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>but have you considered using a 10mm LED?

I’m not opposed to doing the whole thing from parts… just thought re-purposing an existing light might be easier as a first project.

I do have a soldering iron in case I go that other route, but I could do with a refresher on basic electronics.

Might be fun to do it that way too. Maybe I’ll do that… or if not right away, maybe as a second project. Thanks for the suggestion!

Yes the bubble tea sized straw was what I had in mind. They are easy to find around here even without ebay Smile . The AAA fits nicely inside with just enough wiggle room for a thin metal strip or wire.

skinny_tie
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The SingFire SF – 348 seems to be about as thin as a AAA light can get, and it has a single mode click switch. I don’t own one so I have no idea how hard it would be to disassemble, but if you can’t get it apart or you break it you haven’t lost much.

https://www.gearbest.com/led-flashlights/pp_131992.html?lkid=10391326

If it’s really hard to disassemble you could try cutting the battery tube just below the driver. There will be a bit of extra weight from the tube that’s left, but it would keep the lens, reflector, emitter and driver together.

carbone
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Thanks, yes that does look like a thin and simple flashlight… great suggestion! Not sure how hard it would be either but I ordered one and am going to give it a try. Will try other lights too in the meantime if I find any promising ones.

carbone
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Tried to crack open another LED flashlight and that one too was hard (didn’t succeed yet) to open.

Is this a common thing, for the LED part of the flashlight to be pretty locked up?

Zulumoose
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Olight I3e-eos is barely bigger than a AAA, weighs almost nothing, and can take a lot of abuse. I would check that out before thinking about building anything.

Beam me up!

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pretty sure the 348 unscrews at the head, it definitely unscrews at the tail
wle

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The 348 is the slimmest AAA light with its 12mm diameter, but it’s 90mm long and not light weight because it’s stainless steel.
The Olight i3E is the shortest AAA light as far as i know, it’s only 61mm long (when turned off, 60mm when turned on), the head is 14mm wide.
The Olight is hell to modify, because it has the LED soldered on the driver PCB…
The 348 is a lot easier to modify, it has a brass pill with a driver PCB in the rear and a tiny LED board on the front.

The Olight i3E is absolutely not the quality of the i3S.
In fact, it’s a bit of a POS…
I killed the original Luxeon LED by twisting the head too tight (turning it on).
The Luxeon LED has a ridiculous footprint, so i was forced to spend hours fitting a 1mm XP LED board…
I had to sand down the driver PCB to about 0.25 mm thickness and had to make through holes for LED wires, etcetera…
A nightmare that fortunately ended quite well.
It now has a XP-G3 behind its TIR optic and reasonable thermal path to the battery tube when turned on.
I have the ‘silver’ i3E version (has a bit more power) and it’s pretty bright.

Anyway, some weight was added, but it’s still only 8 grams (0.28 oz).
They’re sold as Thorfire too by the way.

The SF348 weighs 26.1 grams (0.92 oz)

Looking for:

5” parabolic reflector (for recoil light)

carbone
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Zulumoose wrote:
Olight I3e-eos is barely bigger than a AAA, weighs almost nothing, and can take a lot of abuse. I would check that out before thinking about building anything.

Thanks, I will check that out! But my definition of “weighs almost nothing” might be different from yours ;-).

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wle wrote:
pretty sure the 348 unscrews at the head, it definitely unscrews at the tail wle

Good to know. Ordered one.

carbone
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Jerommel wrote:
The 348 is the slimmest AAA light with its 12mm diameter, but it’s 90mm long and not light weight because it’s stainless steel. The Olight i3E…

Wow lots of good info here! Thanks. We’ll see what I come up with… will post the results at some point.

Zulumoose
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Have just checked on my scale, olight is 8g, aaa Nimh Duracell is 12g, and an AA alkaline is 24g. So the Olight with battery is lighter than a bare AA battery and looks like it is possibly smaller in volume, though slightly longer.

Beam me up!

carbone
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8g, that is pretty good for off the shelf. I’m using ultimate lithium batteries which are 7.77g on my scale… (are they well regarded in the flashlight world? …not exactly budget, but maybe they are when you factor in the value of long shelf life.) My hope would be to eliminate most of that 8g and bring the total weight including battery down to around 10g but we’ll see.

Just for perspective on weight, I recently made (well girlfriend did most of the work) a string backpack that weighs 10.61g including its carrying bag, and is capable of carrying my laptop, which is sort of a medium laptop in terms of weight (old 13” MacBook Pro). In its carrying bag it’s about the size of a walnut… outside of its bag it’s a little bigger than a laptop. Yeah I’m what they call a gram weenie.

Zulumoose
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If you take the head off the olight it probably weighs 4g, can’t check it right now.
That gives you everything you need except a return path for the negative at the back of the battery.
If you can make a spring mechanism that holds the battery in by pushing the back end, you have a functioning light at about 4g. The positive end of the battery will sit 1cm inside the head so it will be quite secure, and if you splay the head apart by 1-2mm an AA will also fit, giving you much longer battery life, but heat dissipation might be an issue unless you add resistance to reduce the current.

Beam me up!

carbone
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Yes that’s actually what I’ve been thinking! I got the copper one today, not going to destroy that one (it’s also heavy), but have an aluminum one coming in another day. Another idea is to cut away all but a couple thin rails of metal, just enough to hold the battery contact in place, and replace the missing material with light fabric.

This won’t be a light for daily use. It will be more just a lightweight part of a small kit… more as a backup than an everyday light.

carbone
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Let’s see if I can do this image thing. Off topic of lights, but here’s the ultra-light string backpack:

Compared with the weight of some US coins:

Zulumoose
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Looks good. You can get something similar in outdoor shops here made of (I think) parachute material, also comes in a bag about the same size.

Beam me up!

wle
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the singfire 348 does unscrew at the head, you can take the lens and the driver/led out and use in your bubble straw Smile

wle

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Zulumoose wrote:
Looks good. You can get something similar in outdoor shops here made of (I think) parachute material, also comes in a bag about the same size.

Yes you should weigh one of them and see who wins ;-).

carbone
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wle wrote:
the singfire 348 does unscrew at the head, you can take the lens and the driver/led out and use in your bubble straw Smile

wle

Nice. I have ordered one but it seems that the shipping will take a little while. Looking forward to it!

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wle wrote:
the singfire 348 does unscrew at the head, you can take the lens and the driver/led out and use in your bubble straw Smile

wle

Well it arrived, earlier than expected, and I can’t figure out how to unscrew it at the head. Any tips?

Lexel
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Push the head on a rubber surface and twitst the body

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carbone wrote:
wle wrote:
the singfire 348 does unscrew at the head, you can take the lens and the driver/led out and use in your bubble straw Smile

wle

Well it arrived, earlier than expected, and I can’t figure out how to unscrew it at the head. Any tips?


I had a few that wouldn’t unscrew either.
I used pliers because nothing else worked.
Yes, it did leave some tiny marks…

Looking for:

5” parabolic reflector (for recoil light)

Jerommel
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By the way, since you’re in USA, maybe check out the Olight store on AliExpress (that unfortunately doesn’t ship to NL EU).
They recently had the i3S on sale.
The i3S has 3 brightness modes: low – high – moon.
It may be too heavy for your liking though, but it’s a sweet little light, has the best twisty switching i know of.
It weighs 0.43 oz (12.1 grams).

Looking for:

5” parabolic reflector (for recoil light)

carbone
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Jerommel wrote:
By the way, since you’re in USA, maybe check out the Olight store on AliExpress (that unfortunately doesn’t ship to NL EU). They recently had the i3S on sale. The i3S has 3 brightness modes: low – high – moon. It may be too heavy for your liking though, but it’s a sweet little light, has the best twisty switching i know of. It weighs 0.43 oz (12.1 grams).

By coincidence I did recently order one (edit: based on what Jerommel said earlier)! Waiting for delivery. But in this case I didn’t care so much about weight, and got the heavy brass one (the coated one just because I’m unsure about whether the raw brass would have any lead which I’m not interested in absorbing into my skin).

Thanks for validating my purchase ;-).

carbone
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“based on what Jerommel said earlier” well, duh, that would be you! Wink

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what you gain in weight you lose in ability to make it bright .
lights use the whole light /body and even your hand as a heatsink .
give and take what you gain you also lose . give the g3 to grandma
the lithium is an easy way to lose weight .downside is just the price .

carbone
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Time for a progress report…

Version 1 of the ultralight AAA flashlight is done!

Final weight for this version is 4.77 grams without the AAA battery. Not as low as my initial overly optimistic goal, but not bad. With the battery, the weight depends on the battery, but with an Energizer Ultimate Lithium for example, the weight is 12.5 grams total including the battery.

I’m pretty happy with this overall package weight.

What makes up most of the 4.77 grams? Well for one thing there is a solid metal bar spanning from the back to the front of the battery. This part is sourced from a cheap flashlight I got at a surplus place, and cut down. That cheap flashlight is unbranded and is a 2 AA light with four old-school LED bulbs… the metal strip was serving the same role in that light so I just took it out and snipped it in a couple places.

Then another heavy part is the pill, which seems to have significant metal mass to it, probably for heat dissipation. This comes from the SingFire 348 (thanks skinny_tie for suggesting the SingFire, and wle and Lexel for helpful tips!). Based on what I saw with the Olight i3e pill, the 348’s pill seems comparatively heavy; I will have to do a weight comparison on a scale.

But the i3e pill was too big for the straw. I could attach it on to the end of the straw with some heat shrink tape, but that seemed to complicate things and the SingFire 348 pill allowed a much more straightforward solution.

The SingFire head is tricky to open because you have to know that only the very edge (about 2mm or approx 1/8 inch) turns. So if you use a tool like pliers, they need to be applied to the very tip of the 348 flashlight.

The parts are: bubble tea / boba-type straw, battery, metal strip, pill, reflector, cover glass, and lanyard.

Everything pops into a straw, with the lens being glued in place on one end with Gorilla Glue, and the bent metal strip follows the battery into the package to provide some friction that holds the battery in place. A small tab at the back end of the straw holds the lanyard.

A couple of drawbacks: First, you need to hold the “button” (the metal strip) with constant finger or thumb pressure for as long as you want light. Second, I’m not sure this thing would pass a drop test. But for the weight, it seems pretty OK. I’m very happy with the weight of this version, and it also works well, stays together simply, is not very fiddly to use, and the battery is fairly easy to change. There’s also a small cosmetic flaw, with some extra glue mess around the edges of the lens… I’m going to see if I can do a better job on that next time.

BTW the weight listed includes the lanyard ;-).

Pictures soon…

carbone
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Picture album link:

Ultralight AAA at imgur

(Below) Proof of light. A big THANK YOU to the posters on budgetlightforum.com who suggested ways to start on this project.

(All pictures shown here are below the captions, unlike on the image album linked above where the pictures go above the captions) So below is the weight in grams of all parts without battery.

Weight with battery. This type of battery is lighter than normal alkalines so ymmv. The electronics assembly, LED, reflector, and lens come from a $5 flashlight called a SingFire 348, which is very slim and can be opened at both ends. The straw is a boba (bubble) tea straw.

Front side view showing slightly messy glue job on lens.

Here’s what it looks like during assembly. The metal strip needs to be pushed down (in) to hold the battery in place. The curved nib nub will go past the lanyard and provide extra friction.

Closeup during assembly.

Another closeup during assembly. Assembly happens each time you need to change a battery, and is just a matter of putting the strip back in on top of the new battery, after you took it out to remove the old battery.

Assembled and ready for action, rear view. Note the curve in the metal strip is now pushed in past the lanyard. The metal strip is a cut down part from an old flashlight. To activate, put pressure on the metal strip with a thumb or finger.

Light in action:

As I said earlier, the goal was not to make something waterproof, or something blast resistant. Also it wasn’t a goal for it to be rugged, or something that will be a headlamp, or a main EDC flashlight. The goal is just to have a backup light that 1) is cheap 2) is ultra-light 3) uses AAA batteries 4) easy to store 5) simple to use (though limited… one mode, must press to turn on, etc.) 6) Could conceivabley be partially flattened and stored apart from its batteries in space-constrained situations where batteries can be obtained from a separate battery source such as a shared pool of AAA device batteries.

What would I like to improve? Well, making it stronger would be nice. The reliance on glue for holding the front together is downright embarrassing, heh. Also I’d like to get the size down further so it can fit in an Altoids smalls tin, which this one can’t. Having a true on/off would be great but isn’t really a goal. Drop resistance would be good but this is not there yet. Some things have to give… there are tradeoffs for being ultralight, but to me this is an interesting starting point.

Anybody have ideas for improvements? Smile I’m already thinking about how to make this lighter.

Zulumoose
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For storage, you might want to wrap a loop or two of the lanyard between the battery and “tailswitch” so that there is not accidental pressure causing activation, or have a plastic flap that must be flipped/rotated out of the way.

Beam me up!

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