Smart dust" devices are tiny wireless microelectromechanical sensors (MEMS) that can detect everything from light to vibrations. Thanks to recent breakthroughs in silicon and fabrication techniques, these "motes" could eventually be the size of a grain of sand, though each would contain sensors, computing circuits, bidirectional wireless communications technology and a power supply. Motes would gather scads of data, run computations and communicate that information using two-way band radio between motes at distances approaching 1,000 feet.

The goal for researchers is to get these chips down to 1mm on a side. Current motes are about 5mm, says Kristofer Pister, professor of electrical engineering at UC Berkeley, who's been working with smart dust since 1997.

The cost of motes has been dropping steadily. Prices range from $50 to $100 each today, and Pister anticipates that they will fall to $1 within five years.