More Power Over the Air

Posted by Chuck Harrell on Aug 6, 2015 2:00:00 PM

Wireless-Icon-2Cordless power has long been touted as a way of getting away from one of the last remaining restrictions to a truly mobile working life.   At present, if you want to be sure that your phone or laptop won't run out of power at the most crucial moment, you have to carry a power cable with you.

Some phones can be charged wirelessly, but they still need to be placed on a unit that is plugged in.  But now, a new technology is developing a way of powering all manner of devices using a Wi-Fi signal coming from a wireless router.

At the moment your wireless router send out one watt of power (set by the FCC), but that just disappears into the ether, what PoWifi (Power Wi-Fi) does is capture that one watt and convert it to DC power using a harvester.

Unfortunately, this one watt is only a fifth of the five watts required to power a cell phone, but since this is still in the research phase at the University of Washington, it's still early.  What they have managed to do is charge a super capacitor from 17 feet away from the router.  After 35 minutes of charging, enough power was captures to enable a camera to take a picture and after two and a half hours, a fitness tracker was charged to 41 percent.  These aren't exactly great figures, but since they use existing equipment to transmit both power and data at the same time, there are potential benefits.

Another company, which has products coming out in 2016, is doing a similar thing but using bespoke devices which promise to be able to charge a cell phone.

Energous has developed a system which can send one watt of power to up to four devices at the same time up to 15 feet or if you move the devices within five feet, four watts can be delivered.   But, these still need a separate transmitter and receiver which immediately limit their potential.

Although this is interesting technology, I wouldn't get too excited about being able to ditch the power cord just yet.

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