Teenager's Flashlight Gets Its Power From Body Heat
July 2, 2013

Teen Girl Invents Hollow Flashlight

Michael Harper for redOrbit.com - Your Universe Online

A 15-year old girl from Canada has invented a flashlight that doesn't require any battery power. The Hollow Flashlight captures the energy expended by all living humans: Heat.

Saying she became fascinated with "harvesting surplus energy" when she realized humans are constantly exerting power without using it, she looked to Peltier tiles to capture body heat and convert it into usable light. The end result is precisely what the Canadian teen claims, a completely hollow flashlight which can produce useable light with a simple touch of the hand.

More than just a nifty gadget, the hollow flashlight can be used in all manner of emergency situations. Batteries are prone to running out of energy or needing to be recharged. Furthermore, dead batteries can be difficult to dispose of properly and a hollow flashlight could keep batteries out of landfills.

Finally, a battery-less flashlight can always be trusted to work in the most urgent of situations without worrying if there's enough power stored within.

The 15-year old Ann Makosinski will now compete in Google's online science fair in September where the winner will receive a $50,000 scholarship and a trip to the Galapagos Islands.

According to CBC News, Makosinski has been entering science fairs since the 6th grade and has always been interested in alternative energy sources.

"I'm really interested in harvesting surplus energy, energy that surrounds but we never really use," said Makosinski in an interview with the news agency.

The key component of the hollow flashlight is Peltier tiles, pieces of material which conduct energy when they're met with two different temperatures. When one side of the tile is warmed and the other cooled by air, the tiles can produce energy. After researching these tiles, Makosinski did some quick calculations and found that the amount of energy produced is enough to power a light bulb. While the tiles produced enough energy from the human hand, she still needed a higher voltage from the tiles to pump energy to the LED bulbs. She then applied some changes to the circuitry and added transformers to boost the voltage and deliver light to the bulbs.

Heating one side of the tile was easy enough; the human hand creates just enough heat to power the tiles and create energy. Next Makosinski had to discover a way to cool the other side of the tiles. She built two prototypes of the Hollow Flashlight, one built with an aluminum tube to transfer the cooler ambient air to the underside of the Peltier tile and a second which housed the aluminum in a PVC pipe, allowing just enough skin contact to heat the top side of the tiles.

In her experiments, she found both models put out ample light for about 20 minutes at a time, but the results were much better when the ambient temperature was somewhere near 40 degrees and 50 degrees Fahrenheit. There only needs to be a difference of about 10 degrees Fahrenheit to power the Hollow Flashlight, says Makosinski.

All told, Makosinski said she was able to build the flashlights for about $26, but if these things ever became mass produced, she's sure they could be made even cheaper.