'Power Over Wi-Fi' named one of the year's game-changing technologies

November 18, 2015 by Jennifer Langston
The UW team used ambient signals from this Wi-Fi router to power sensors in a low-resolution camera and other devices. Credit: Dennis Wise/University of Washington

University of Washington engineers have developed a novel technology that uses a Wi-Fi router—a source of ubiquitous but untapped energy in indoor environments—to power devices.

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" awards announced Wednesday.

The technology attracted attention earlier this year when researchers published an online paper showing how they harvested energy from Wi-Fi signals to power a simple temperature sensor, a low-resolution grayscale camera and a charger for a Jawbone activity tracking bracelet.

The final paper will be presented next month at the Association for Computing Machinery's CoNEXT 2015 conference in Heidelberg, Germany, on emerging networking experiments and technologies.

"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.

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 percent in 2.5 hours.

The researchers also tested the PoWiFi system in six homes. Users typically didn't 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.

Although initial experiments harvested relatively small amounts of power, the UW team believes there's opportunity for make the PoWiFi system more efficient and robust.

"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 numerous more sensors and applications," said co-author Shyam Gollakota, assistant professor of computer science and engineering.

Explore further: No-power Wi-Fi connectivity could fuel internet of things reality

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9 comments

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ab3a
5 / 5 (2) Nov 19, 2015
They're using JUST the energy from WiFi? Why not use energy from nearby MW and VHF broadcast stations?
HocusLocus
5 / 5 (3) Nov 20, 2015
There is NO way to use these tuned devices without creating drop-off zones behind them. This is vulture idiot technology, where a marginal idea is oversold to gullible people who are led by the tech writing to imagine it 'scaling' somehow in a way that is not only usable --- but is more cost effective than solving the original problem: how to power small devices.

If there is such a thing as an engineer-sociopath, those who front this idea (or any Teslaesque long distance power solution) are they. For example... in order to increase energy output of the base they essentially zombify it to flood the airwaves with bogus 'traffic'. Smooth WiFi operation depends on sensible use according to need. They may argue that data can be carried in these packets, but what if it's your neighbors on all sides surrounding you with zombie routers, saturating the airwaves? Because they cannot be bothered to change a freaking battery in a WiFi thermostat.

Impolite.
KBK
1 / 5 (4) Nov 20, 2015
It is also sheer off the scale insanity to saturate the airwaves with RF, for power purposes.

This is not technology, this is idiot death on wheels.

Unfuckingbelivably stupid.

This needs to die ---and die fast.

Why don't we just have everyone eat poison instead? Here's a mouthful of strong cacrinogens!

Eat them every day!

This idea of RF powering your devices is just as insane as direct poisoning of people.
TheGhostofOtto1923
4 / 5 (4) Nov 21, 2015
It is also sheer off the scale insanity to saturate the airwaves with RF, for power purposes.

This is not technology, this is idiot death on wheels.

Unfuckingbelivably stupid.

This needs to die ---and die fast.

Why don't we just have everyone eat poison instead? Here's a mouthful of strong cacrinogens!

Eat them every day!

This idea of RF powering your devices is just as insane as direct poisoning of people.
Uh you got anything besides vitriol to argue with? Cold hard facts for instance?
SuperThunder
3 / 5 (2) Nov 21, 2015
I downloaded the Top Rated App of 2017 : Vampower(tm). It allows me to ping all the phones in a two hundred meter radius to make them burn their battery emitting radiation that my phone then harvests to recharge its battery.

I hate the pop-up ads though.
Captain Stumpy
5 / 5 (2) Nov 21, 2015
It allows me to ping all the phones in a two hundred meter radius to make them burn their battery emitting radiation that my phone then harvests to recharge its battery
@SuperT
huh... that explains a lot
you're not invited near my house again

LOL

.

i am going to invent a new pop-up ad that automatically links every other possible pop-up ad on the net (regardless of language) and makes it pop-up right after the initial pop-up (closed, cancelled or not) and then loops in on itself making itself the last popup which automatically restarts the process again, just for your cell phone
LMFAO
yerfooked.popup.ad.net

of course, i will also pay google and every possible search engine on the net to link it to every pseudoscience page out there
LOL

[sarc/hyperbole]
SuperThunder
3 / 5 (2) Nov 21, 2015
You could use the database from AdBlockPlus to create the ad-oscillator, the adscillator, er, adorocitor. I like adorocitor.
MR166
5 / 5 (1) Nov 22, 2015
I would venture to guess that 90% of the applications envisioned for this technology could be powered by something as simple as a solar cell. The camera mentioned is a prime example of this. The only interesting part of the article is that they can develop useful circuits that can operate on such a minuscule amount of power. I would venture to guess that by the time you include the size of the antenna into the product it could just as easily be powered for 10 years by a battery and still be smaller.
ab3a
5 / 5 (1) Nov 22, 2015
MR166, that's a very good point. Typically energy harvesting circuits use whatever ambient energy is available to charge a capacitor. When sufficient charge is accumulated, it then does something, draining the capacitor, and then the process starts all over again.

I've seen vibration used for energy, Peltier junctions used for energy, solar cells used for energy, and so on. Or... one could use a coin cell battery and it will probably last for the lifetime of the sensor. It hardly matters where the energy comes from, just that it be there and be reliable.

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