New tech uses Wi-Fi signals to power devices

Researchers, including those of Indian-origin, have developed a novel technology that uses a Wi-Fi router to wirelessly power devices such as cameras without degrading the quality of your internet signal.
The Power Over Wi-Fi (PoWiFi) system is one of the most innovative and game-changing technologies of the year, according to Popular Science, which included it in the magazine's annual "Best of What's New 2015" awards announced yesterday, researchers said.
"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 University of Washington (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," said Talla.
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, researchers said.
But one major challenge is how to energise those low-power sensors and actuators without needing to plug them into a power source as they become smaller and more numerous.

The team 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.

However, because the signals are sent intermittently, energy "leaked" out of the system during silent periods.
The team fixed that problem by optimising 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.
In their proof-of-concept experiments, the team demonstrated that the PoWiFi system could wirelessly power a grayscale, low-power Omnivision VGA camera from 17 feet away, allowing it to store enough energy to capture an image every 35 minutes.

It also re-charged the battery of a Jawbone Up24 wearable fitness tracker from zero to 41 per cent in 2.5 hours.
The researchers also tested the PoWiFi system in six homes. Users typically did not notice deterioration in web page loading or video streaming experiences, showing the technology could successfully deliver power via Wi-Fi in real-world conditions without degrading network performance.
"In the future, PoWi-Fi could leverage technology power scaling to further improve the efficiency of the system to enable operation at larger distances and power numerous more sensors and applications," said co-author Shyam Gollakota, assistant professor of computer science and engineering.