Ann Makosinski is a 15-year-old who won a bronze award for a piezoelectric flashlight at the Canada-Wide Science Fair last year. This year, her battery-free Hollow Flashlight has taken her all the way to the top-15 finalists of the Google Science Fair.
Inspired by the idea that the human body is like a walking 100-watt lightbulb with untapped thermal energy potential, Makosinski decided to build a flashlight powered only by the warmth of a hand.
The basis for the Hollow Flashlight is Peltier tiles, tiles that produce electricity when one side is heated and the other side cooled.
Two working prototypes later, Makosinski was able to prove her concept that the warmth of the human hand could power a flashlight. It requires 5 degrees Celsius differential between the surrounding atmosphere and the hand. The flashlight is constructed from a hollow aluminum tube to allow ambient air inside.
The Hollow Flashlight does offer a usable amount of illumination, without cumbersome batteries.
“I made two flashlights that do not use any batteries, toxic chemicals, or kinetic energy. They do not create any noise or vibrations and will always work. The flashlight’s only limitation is its need for at least a 5°C temperature difference to provide usable light,” Makosinski writes.
The Hollow Flashlight project should stand as a bright beacon of hope in that regards. You can watch a YouTube demo of the flashlight here.