Wi-Fi charging at home seemed like something in science fiction for a long time, but now there’s major research going into this region of wireless power transfer with the utilization your simple router in your home.
In Seattle, six homes took part in the experiment in which modified electrical devices were placed in their home with a normal router. Over a period of 24 hours the devices where powered solely by the routers signal, which was also still able to supply the usual internet connection.
So how is this possible?
Radio waves carry with them a small amount of energy, as they are transmitting this energy your device receives it and normally converts it into data, however with this device instead of it being converted to data it is converted to power using a rectifier, then the voltage is boosted using a DC to DC converter.
(arxiv.org/abs/1505.06815).
This system was able to power temperature sensors and battery-less low resolution cameras and normal standard batteries. However charging the batteries was not the difficult part, this was found in pushing the energy continuously from the router.
This is due to the fact when someone is streaming data the signal is active however when they are not streaming this data the signal drops to almost zero. However to get around this issue the time designed a piece of software that can broadcast data all the time which will now constantly utilize the Wi-Fi channel.
The team say that small devices such as those that are integrated into the internet of things can really benefit from this technology, says Ben Potter at the university of Reading UK. However Wi-Fi technology in this state will never provide us with such power for primary or conventional devices e.g mobile phones or laptops.
As Wi-Fi signals are tightly regulated in many countries to 1 watt broadcasting power which would be enough providing the system stays in proximity of the transmitter long enough, another problem is the load of users which the system would broadcast too, as this can significantly impact the power output of the device.
A company called Ossia in Bellevue, Washington has a integrated system called Cota into its routers. Doing this the routers can produce the 20 watts needed and in doing this supply 1 watt to a small range of devices without using a communications signal therefore allowing constant power to be delivered to the device.
“Unlike Wi-Fi, our power signal is unmodulated,” says Zeine. “It’s a continuous wave, there’s no message in it.”
The receiver ship on the device being charged communicates with the Cota’s hub which consists of thousands of antennas alerting it to its presence, the hub responds to this by keeping active the antennas the device is connected to so a solid signal is maintained.
Eric Woods, an IT infrastructure researcher at the consultancy firm Navigant in London thinks that this technology will in high demand in the future, and has a large possible market once the technology develops further.