Wi-Fi chips in devices such as smartphones and laptops communicate by generating radio signals, an act that requires a substantial amount of power.
Shyam Gollakota uncovered a way to create Wi-Fi signals without radio transistors. And here’s the real payoff: These “passive Wi-Fi” devices use 10,000 times less power than a typical Wi-Fi chip, and 1,000 times less power than the most efficient Bluetooth, thereby significantly reducing the need for battery power.
Gollakota then saw an opportunity to actually harness power from the invisible world of those signals themselves: What little power these wireless devices still require can be delivered over Wi-Fi. Gollakota and his team devised a way to send power over the unused channels of a traditional Wi-Fi network. The team demonstrated that they could power battery-free sensors and tiny cameras at distances of up to 20 feet, and recharge batteries 28 feet away without significantly slowing down data rates.
“Now you can have completely battery-free devices,” Gollakota says. This is what computer science is all about, he says, “trying to understand and solve actual human problems.”