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15-year-old student invents flashlight that runs on human body heat

A 15-year-old student is one of the Google Science Fair finalists, after submitting a $26 flashlight that runs on human body heat. The top awards will be handed out in September, but Ann Makosinski, a high school junior from Canada, has already achieved something impressive simply by making the list of finalists. The contest will select three age category winners and one grand prize winner, who will receive $50,000 and a trip to the Galapagos Island. With an easily marketable product, however, Makosinski will likely see her vision turn into reality regardless of whether she wins or not.

Makosinski became interested in harvesting energy from the surrounding environment, and this interest drew her to Peltier tiles. Peltier tiles, which are used in devices like heat sinks, produce electricity when one side of the device is heated and the other is cooled, Extreme Tech explains. Makosinski wondered whether this technology could be used to build flashlights that have no need for batteries. She utilized Peltier tiles in her flashlight design and they provided enough power for the flashlight to produce light through an LED bulb, but not enough voltage.

While seeking ways to increase the voltage, she built transformers into her prototype and built her own circuits to try to reach the necessary voltage. Eventually, Makosinski found a circuit that worked, and was able to submit her flashlight to the contest. The flashlight stayed powered for about 20 minutes, long enough to take a short walk if necessary or to find some candles in a power outage.

The flashlight still has one clear drawback that limits its usefulness: it only works in cold weather. Makosinski tested the flashlight at 41 degrees Fahrenheit, and the flashlight worked, though not as well, up to 50 degrees Fahrenheit. The reason behind this limitation is that the Peltier tiles work better in colder temperatures since they operate off a temperature contrast. If the flashlight is used in hot weather, there is no real difference between the atmospheric temperature and the temperature of the user’s hand. Still, with a total cost of only $26, the flashlight definitely is marketable, and Makosinski could use the prize money to help her solve the problem of the flashlight’s temperature requirements, should she so choose.

The prize contest will be held in Mountain View, California, where the finalists will present their projects to a board of judges who will in turn select the winner. Makosinski, who has been submitting projects to science fairs since grade six, is simply excited to present to the board, many of whom are fellow scientists, she told CBS News.