The most important element of any flashlight is its battery, which sooner or later discharges. The Lumen flashlight is an exception to this rule. He does not need a battery, since it is replaced by the warmth of a human hand.
Lumen is the size of a human finger. It uses a small thermoelectric generator as a power source. The light source is the widely used 5mm super bright Cree LED.
The warmth of the hand is converted into electricity due to the difference in temperature between the body and the environment. So, for example, at a temperature of +28 degrees, the generator will give out a current of 15 mA, which is quite enough to power the LED. If this value is exceeded, then the surplus will go to the “zagashnik” - to the internal capacitor.
The body of the flashlight is made in two versions - aluminum and titanium. In the first case, it weighs 35 g, and in the second - 45 g. The choice of metals is not accidental. They are not only durable, but also act as a radiator, which makes the thermoelectric generator more efficient.
The project is currently funded through Kickstarter and has already raised $ 5, 000 in 2 days. The aluminum version of the Lumen will cost $ 35, the titanium version - $ 45. Sales are expected to start in February 2016.