A UW research project that seeks to power the Internet of Things using Wi-Fi signals – dubbed “power over Wi-Fi” or “PoWiFi” for short – is the topic of a recent paper and an article in MIT Technology Review. The project was developed by a team that includes CSE professor Shyam Gollakota, CSE and EE professor Josh Smith, EE Ph.D. student Vamsi Talla, CSE alum (and current EE Ph.D. student) Bryce Kellogg, former CSE postdoc Ben Ransford, and EE Ph.D. student Saman Naderiparizi.
From the article:
“The idea is simple in concept. Wi-Fi radio broadcasts are a form of energy that a simple antenna can pick up. Until now, Wi-Fi receivers have all been designed to harvest the information that these broadcasts carry. But Talla and co point out that there is no reason why the energy shouldn’t be harvested as well. The question is how much can be gathered in this way. And therein lies the challenge …
“The problem is that Wi-Fi broadcasts are not continuous. Routers tend to broadcast on a single channel in bursts. This provides enough power for the sensor but as soon as the broadcast stops, the voltages drop … That gave Talla and pals an idea. Why not program the router to broadcast noise when it is not broadcasting information and employ adjacent Wi-Fi channels to carry it so that it doesn’t interfere with data rates.”
Calling the results “impressive,” the article explains how the researchers used their new PoWiFi system to wirelessly power a battery-free temperature sensor and a camera without compromising network performance, in real-world conditions. They also were able to recharge coin-cell batteries using PoWiFi from distances of up to 28 feet.
The article concludes:
“The ability to deliver power wirelessly to a wide range of autonomous devices and sensors is hugely significant. But the real icing on the cake here is the ability to do this with ordinary technology that is commonly available all over the developed world and beyond. As such, PoWi-Fi could be the enabling technology that finally brings the Internet of Things to life.”
Read the complete article here.
Read a PDF of the team’s paper, “Powering the Next Billion Devices with WiFi,” here.