Battery-free sensor tag gathers energy from radio frequenciesWiliot could put connected tags on your clothes and food.By J. Fingas, 01.15.2019
9Matrix adds a solar cell to its battery-free smartwatchThe company claims it can do GPS and optical heart-rate tracking without a battery.By D. Cooper, 01.06.2019
University of Washington harnesses RF and TV waves for battery-free wireless devices (video)By T. Seppala, 08.15.2013