Picoradio at UC Berkeley
A UC Berkeley researcher is developing small 100-microwatt transmitters for very short-range, low-bandwidth wireless networks:
Each node, in its final form, will be no bigger than a shirt button and will contain several elements: a sensor, or set of sensors, for measuring elements like temperature, pressure, motion, light or sound; a microprocessor; an interface to communicate with other nodes; and a power component, either solar cells or a piezoelectric polymer that can convert vibrations from the environment into electricity.