The work of Josh Smith (UW CSE and EE) is described:
“But how do you charge something so small? ‘The vision of blanketing the world with smart sensors is very compelling,’ says Joshua Smith, head of the Sensor Systems Laboratory at the University of Washington in Seattle. ‘But a lot of sensor networks researchers found themselves surrounded by mountains of depleted batteries and dead sensor nodes.’
“So, like microscopic Robinson Crusoes, the motes will live off the power they can scavenge from their surroundings. A mote near a light source might use a tiny solar panel, while a mote running somewhere with greater temperature extremes can be built to tap into that, by converting the heat energy that flows between hot and cold into electricity.”
Read more here.