If your running jacket were lined with power felt, perhaps your body heat could power your MP3 player while you jog.

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You've probably had this experience: You're on the go all day and haven't had a chance to plug in your iPhone, and just when you need to make a call or check your e-mail, you see that little red icon that indicates your battery is just about to run out. It's so frustrating it actually makes you get a little hot under the collar. But wait -- maybe that's the solution. What if, instead of blowing a gasket, you could somehow convert that excess body heat into electricity and use it to power your phone or another portable device?

You've actually seen a variation of this idea before, if you're a fan of the cinematic "Matrix" trilogy, in which a giant computer network powers itself by siphoning energy from legions of comatose, unwitting human beings. We're not talking about anything that creepy, though. Small-scale thermoelectric power generation, in which body heat is harvested to power portable devices, is a concept that scientists have been looking at quite intently in recent years -- as our craving to carry power-hungry gadgetry in our pockets has continued to grow.

Recently, researchers at Wake Forest University's Center for Nanotechnology and Molecular Materials gave a boost to thermoelectric power generation's prospects when they developed a fabriclike material called "power felt," which is capable of exploiting differences between an object's heat and the room temperature to generate an electrical charge [source: Neal].

One researcher who's worked on the project envisions fashioning a jacket from power felt and using it to power an iPod, an idea that sounds pretty great for cool-weather jogging enthusiasts. But power felt doesn't just have to go in a garment. A flashlight handle swathed in power felt might be a great thing to have during an extended power outage, and a car seat made of the stuff might draw energy from your posterior to power your windows or radio. And there are other non-human energy sources that we might use it to tap, as well [source: Neal].