Designers Mathieu Servais, Camille Lefer, Clément Faydi and Mickaël Denié have created the Dyson Energy bracelet that generates power from your wrist. It "uses Seebeck effect to harness energy and power your mobile phones for a few precious minutes more..."
"The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. This typically includes three separately identified effects, the Seebeck effect, the Peltier effect, and the Thomson effect." source
Finding an alternative source to generate voltage is one amazing accomplishment, but I wonder if the thermoelectric effect will generate enough current to power most devices. This is a terrific concept and I hope the designers continue to push the boundaries on what is possible.
Here's a vid of the concept: