These days we're surrounded by Wi-Fi pretty much everywhere we go, but are we leaving a lot of the potential of this technology untapped?
Yes, according to a team of engineers at the University of Washington, who have developed a new system called Power Over Wi-Fi (PoWiFi), which can power devices within a wireless network using the inherent energy of Wi-Fi signals.
"For the first time we've shown that you can use Wi-Fi devices to power the sensors in cameras and other devices," said Vamsi Talla, an electrical engineer and lead author of the study. "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."
The system, which was first announced by the researchers earlier in the year, is set to be presented in a final paper next month at the Association for Computing Machinery's CoNEXT 2015 conference in Germany, with the technology expected to hold considerable appeal for anybody who likes electronic gadgets (that's you) and uses Wi-Fi (also you).
While the idea of electricity flowing wirelessly through the air might sound more than a little alarming, the minimal amounts of current generated by PoWiFi offer no cause for concern. They could, however, be ideal for meeting the needs of low-power sensors in small devices like cameras and fitness trackers (but not smartphones and more powerful equipment, which require more juice).
In developing PoWiFi, the researchers found that the peak energy contained in regular Wi-Fi signals is sufficient to charge or run these kinds of low-power gadgets, but due to the way the signals are only sent intermittently, energy leakage inevitably occurs.
By optimising a router to send out additional power packets on Wi-Fi channels not currently in use – and integrating sensors into low-power devices such that they can feed on the signals – the team was able to make the signal strong and consistent enough to deliver power effectively.
In testing, the researchers showed that PoWiFi distributed enough charge to wirelessly run a low-power VGA camera from more than 5 metres away. It also recharged the battery of a Jawbone Up24 wearable fitness tracker from no charge to 41 percent in 2.5 hours.
In addition to measuring the system's charging abilities, the researchers also tested the impact of running PoWiFi on the router's regular role: delivering Internet access on a local network. In testing in six homes, users typically didn't notice any slower than usual performance when it came to loading web pages or streaming content from the web (which is good, because that would be a deal-breaker).
"In the future, PoWiFi 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 Shyam Gollakota, a co-author of the study.
While the relatively meagre amounts of power delivered by PoWiFi means it can't compare with a standard wired power cable, future refinements to the technology – not to mention the sheer convenience of having all your small devices charge wirelessly around you – could see PoWiFi make one heck of an impact if it gets a consumer release. Here's hoping!