Here’s a product that people here might be interested in. On Kickstarter, an inventor named Rost Zhuravskiy is trying to fund his invention for a flashlight called the Lumen which needs no battery, but runs on body heat. He claims to have developed a thermoelectric generator which generates enough energy to power the LED in the flashlight when you put your thumb on it.
On the Kickstarter page Zhuravskiy provides some details about the technology:
“In my application difference between temperature of your body (about 98 °F) and environment (at least 82 °F) is enough to generate power for single led. Metal body of Lumen serve as a radiator . . . As you understand, we can’t power really high-output led just with touching small TEG. However, when your temperature is 98 °F and air temperature is 82 °F Lumen produce about 15 mA@3v. When difference is bigger – excessive power is stored in a capacitor to power Lumen whenever you need it. Such amount of energy is enough to power 5 mm Cree led with 3000 mCd light output.”
In addition to the flashlight function, there’s another optional feature for the Lumen — you can order a version which has a tritium vial attached, which will glow in the dark for up to 10 years, so when you need to find the flashlight in the dark you will be able to see it.
The cost for the Lumen with an aluminum body is $35, and $45 for an aluminum body. If you pay $15 more for either you get the tritium vial attached.
Remember, this is Kickstarter — so it’s a homemade project without any guarantee, or third-party verification. The flashlight is not being mass-produced yet, and if there is an overwhelming demand, I would expect it could cause production delays. And I do wonder if there might be any consumer safety issues if the flashlights include tritium. So far the project has exceeded its goal of $5000 by far: there are over $50,000 in pledges to date.
Here’s a video: