http://www.gizmag.com/lumen-flashlight/39893/ Powered by body heat, Lumen flashlight never needs batteries Stanley Goodner October 16, 2015 Whether it be for everyday carry (EDC), outdoor adventure, or disaster preparation, flashlights tend to be found towards the top of must-have items. But one common aspect of these luminescent devices is that they're only as good as the batteries inside. If you've ever switched on a flashlight only to experience a flood of frustrated disappointment, you might appreciate owning an "eternal flashlight." Lumen is designed to be powered by body heat, never needing batteries. The finger-sized Lumen flashlight uses a small thermoelectric generator (TEG) to power a single 5-mm ultrabright Cree LED. We've seen successful use of such technology in consumer products before, such as with Power Practical's PowerPot. Researchers have been experimenting with wearable TEGs to extend the battery life of small devices, and, quite famously, a Canadian high school student created a working prototype of a body heat-powered flashlight as a science fair project. Lumen, however, could be the first of its type to be readily available to the general public. Lumen works to transform heat into electricity through a difference of body and ambient air temperatures. So if it happens to be 82 º F (28 º C) where you're at, Lumen is designed to produce about 15 mA at 3 V, enough to power the LED for 3000 mCd (millicandela of output. Any excess power is stored in an internal capacitor. The body of the Lumen flashlight is made of machined aluminum or titanium, weighing 1.2 oz (35 g) for the former and 1.5 oz (45 g) for the latter. These metals are not only durable, but they double as a heat-sink to help make the TEG work more efficiently. While Lumen may not be able to compete with its battery-powered brethren in shear lighting power, it looks to offer more than enough light output to find objects, safely navigate, or read while in the dark. But with Lumen, you get to feel a little greener since you're the energy source and not a battery which, eventually, ends up being disposed. EDC enthusiasts will certainly appreciate the hole drilled through at the bottom, ideal for attaching to gear with split rings or paracord. And those who want to enjoy a bit of extra glow (for up to 10 years) can opt to choose one equipped with a tritium vial. The Lumen flashlight is currently funding on Kickstarter, having raised 326 percent of its US$5,000 goal in just two days, with another 28 days left to go. A pledge of $35 sets you up with one Lumen in machined aluminum, $45 for machined titanium. Units with tritium vials run $15 more for each. If you check out the video below, you can see that the creator's machining equipment appears ready and waiting. So if materials purchasing, production, and assembly go according to schedule, backers can expect shipments of the Lumen flashlight to start sometime in February, 2016. Source: Kickstarter Peace favor your sword, Kirk
~2.5 lumens if that angle is around 60* Candela is spot intensity, and Lumens is total light output but is inverse it appears from the converter I found. In other words, fewer Lumens in a narrow beam appears brighter than the same Lumens spread out. This little light also has a flat sided top and bottom, which helps keep the "beam" in a little tighter. It should be similar to the small key fob lights that are pretty cheap. The "hook" is that it never needs batteries Not the brightness!
It could be a bit brighter than that, the narrow sides constrain the light into a rectangular pattern and the lumen measure is based on a cone shape. It could be anywhere from 2.5 to 7.5 Lm, but I'd estimate around 5-6... Quite Adequate for it's described use. I have that Princeton Tec Tac Light and it has a cone shape "beam" that comes out at 10 lm which describes a circle of maybe 24" to 30" at a range of 5 feet. Quite Bright for building clearing and other CQB needs.
I'm thinking this thing would be ideal to chuck in your BOB or even your "Survival Tin." Never worry about batteries. Looking forward, I'm wondering if this same technology might be applied to a BOB radio with an Emergency Channel tuning range. Maybe in the classic ear-loop format. You could get emergency broadcasts and never worry about batteries. Peace favor your sword, Kirk
Why not just get a crystal radio? They still make the pencil type that has a wire antenna and the adjustable rod tuner
I had an electronics kit as a kid. I remember them. IMS, crystal type radios don't work well with weak signals. Peace favor your sword, Kirk
I think the light is a great idea. Unfortunately, they have 2800+ contributors, and this guy won't be able to make enough for them, much less for sale, so you AREN'T getting one for backing him, for a LONG time, IMHO. Unless he sells out to someone that CAN make a million of them, or they just make their own, this idea will probably die. In the meantime...I like this one: USB Rechargeable. http://www.amazon.com/NITECORE-Rechargeable-Lumens-COLORS-AVAILABLE/dp/B00RGYCRA4/ref=sr_1_6?s=hardware&ie=UTF8&qid=1455743821&sr=1-6&keywords=USB+light
