BuzzSkyline writes: Researchers in Belgium have developed devices to harvest the waste heat our bodies throw off in order to convert it to electricity to run devices such as a wristband blood oxygen sensor and an electrocardiogram shirt. As a side benefit, the power sources help cool you down and keep you looking cool, all while running sundry micropower devices. In fact, the researchers mention that the energy harvesting head band works so well that it can get uncomfortably cold. In that case, they say, "This problem is solved in exactly the same way as someone solves it on the body level in cold weather: a headgear should be worn on top of the system to limit the heat flow and make it comfortable." But it would be such a shame to cover up the golden heat-harvesting headband with a hat. The research was published last month in the Journal of Renewable and Sustainable Energy.