We have seen all sorts of flashlights that don’t need batteries, the first style I remember was the squeeze generator type. Then the shake flashlight seemed to be all the rage, they were so popular that there were even a bunch of fake battery operated ones sold. The one thing I have never seen before was a hand heat powered flashlight. Anne, who is a 15 year old from Victoria BC Canada designed just that. I haven’t see the full specifications of her design but as far as I can tel she uses some Peltier devices to generate electrical energy, this low voltage output was then fed into a device to increase the voltage, something like a joule thief was probably used. This voltage was then connected to some LEDs. When a warm hand is placed on the Peltier devices on the warm side the device outputs electricity since the cold side is placed on a large aluminum heat sink which would easily remain close to room temperature.
What a great job in thinking on this and building it! I would be interested to see how far this concept can be taken. It looks like the concept is a bit dim in the demonstrations but with a bit of tweaking I think it could be made very usable. I am thinking that a super cap built into the device could store the energy while the user is holding it but before it is needed.Â