Energy harvested from our bodies will make possible mind-boggling gadgetry Sensor-studded clothing worn by a soldier tracks his movements and vital signs. A disposable electrocardiogram machine the size of a Band-Aid monitors a heart patient. A cellphone is implanted in a tooth. Scientists and engineers are trying to develop such “embedded” devices: miniature electronics that plug people into computer and communication networks. Consider contact lenses that function as computer screens. A University of Washington research team, led by electrical engineering professor Babak Parviz, has developed a prototype lens fitted with a tiny radio (for receiving data) and a light-emitting diode, or LED (for displaying data to its wearer). The technology has prompted comparisons to the computer readouts…