Tiny tremors in your office or car could soon power all sorts of small gadgets, thanks to MIT materials scientists Robert O'Handley and Jiankang Huang. The pair have developed devices less than five centimeters long that transform slight vibrations into usable electricity. Inside, a spring links a magnet and a coil of copper wire; minuscule movements of the magnet and coil produce an electric current. Attached to a rattling duct or water pump, the device generates a few milliwatts of power-enough to drive, say, a temperature sensor. The duo cofounded Ferro Solutions in Cambridge, MA, which is partnering with Cambridge, MA-based Millennial Net to build battery-free wireless sensors for factory and building management. Other anticipated applications include energy sources for automotive sensors, micromotors in printers, and even cell phones.