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…