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No Batteries, No Problem: This Flashlight Runs on Body Heat - Forever

by Devin Coldewey /
Rost Zhuravskiy

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Batteries are so 20th century. The Lumen is a new flashlight that skips the AAs, producing light by harvesting your body heat, and it's looking for funding on Kickstarter. There are no switches, ports, compartments or anything — just a machined metal frame, a single bright LED, and a big thumbprint where you need to touch the device. Inside, a thermoelectric generator captures energy from the way electrons move around when there's a temperature differential — just enough to provide a little light.

If the idea sounds familiar, you may remember the "Hollow Flashlight," a device created by 15-year-old Anne Makosinski for Google's 2013 Science Fair. They work by the same principle, but the Lumen, from inventor Rost Zhuravskiy, is more compact and efficient — and ready to manufacture.

You can pick one up for as little as $35 if you pre-order, or pay a bit more for a titanium body instead of aluminum. There's even an option that adds a tiny vial of tritium, a radioactive hydrogen isotope (don't worry, it's safe in this small amount), that will glow in the dark for up to 10 years. It might be worth the upgrade just to impress your gadget-loving friends.

Zhuravskiy has already more than tripled his modest $5,000 goal, so if all goes well Lumens should be shipping in early 2016.

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