We present the first power over Wi-Fi system that delivers power to low-power sensors and devices and works with existing Wi-Fi chipsets. We show that a ubiquitous part of wireless communication infrastructure, the Wi-Fi router, can provide far field wireless power without significantly compromising the network's communication performance. Building on our design, we prototype battery-free temperature and camera sensors that we power with Wi-Fi at ranges of 20 and 17 ft, respectively. We also demonstrate the ability to wirelessly trickle-charge nickel–metal hydride and lithium-ion coin-cell batteries at distances of up to 28 ft. We deploy our system in six homes in a metropolitan area and show that it can successfully deliver power via Wi-Fi under real-world network conditions without significantly degrading network performance.
In the late 19th century, Nikola Tesla dreamed of eliminating wires for both power and communication.16 As of the early 21st century, wireless communication is extremely well established—billions of people rely on it every day. Wireless power, however, has not been as successful. In recent years, near-field, short range schemes have gained traction for certain range-limited applications, like powering implanted medical devices20 and recharging cars3 and phones from power delivery mats.8 More recently, researchers have demonstrated the feasibility of powering sensors and devices in the far field using RF signals from TV7 and cellular19 base stations. This is exciting, because in addition to enabling power delivery at farther distances, RF signals can simultaneously charge multiple sensors and devices because of their broadcast nature.
In this work, we show that a ubiquitous part of wireless infrastructure, the Wi-Fi router, can be used to provide far-field wireless power without significantly compromising network performance. This is attractive for three key reasons: