"For the first time we've shown that you can use Wi-Fi devices to power the sensors in cameras and other devices," said lead author Vamsi Talla, a UW electrical engineering doctoral student. "We also made a system that can co-exist as a Wi-Fi router and a power source—it doesn't degrade the quality of your Wi-Fi signals while it's powering devices."
PoWiFi could help enable development of the Internet of Things, where small computing sensors are embedded in everyday objects like cell phones, coffee makers, washing machines, air conditioners, mobile devices, allowing those devices to "talk" to each other. But one major challenge is how to energize those low-power sensors and actuators without needing to plug them into a power source as they become smaller and more numerous.
The team of UW computer science and electrical engineers found that the peak energy contained in untapped, ambient Wi-Fi signals often came close to meeting the operating requirements for some low-power devices. But because the signals are sent intermittently, energy "leaked" out of the system during silent periods.
The team fixed that problem by optimizing a router to send out superfluous "power packets" on Wi-Fi channels not currently in use—essentially beefing up the Wi-Fi signal for power delivery—without affecting the quality and speed of data transmission. The team also developed sensors that can be integrated in devices to harvest the power.