Battery-free surveillance camera is powered by Wi-Fi

A battery-less surveillance camera that draws its power from ambient Wi-Fi signals has been unveiled by PhD student Vamsi Talla and his colleagues from the University of Washington’s Sensor Systems Lab. 

The specially modified camera is able to collect and store power from random, nearby Wi-Fi signals for the purpose of taking photos. The University of Washington team believes the power gathering technique they developed will prove incredibly useful, in particular, to the growing “internet of things” industry.

The technology is referred to as “power-over-Wi-Fi”. The way it works is the camera taps into the energy in Wi-Fi signals which, at the ambient level, comes pretty close to the operating voltages required for most low power devices. 

The thing that previously hurt power-over-Wi-Fi is the fact that these signals are broadcast in bursts and at different frequencies; this means the amount of energy available is too intermittent to be truly useful. To overcome this hurdle, the researchers modified a few standard Wi-Fi hotspots and routers to broadcast noise when a channel was not in use. Doing this, the discovered, allowed the power of the Wi-Fi signals to stay constant and, even though it’s very low, provide enough power to control some components. 

For those familiar with Wi-Fi technologies, it should be noted that adding the noise to the channel did very little in terms of slowing data rates across hotspots. 

Per the actual experiment, the team used the power beaming system found in a temperature sensor and a small surveillance camera several feet away from a Wi-Fi hotspot. The low-power camera gathered energy from the Wi-Fi and stored it in a capacitor that prompted the camera to take a picture when it had enough charge. 

Using this leaching method, if you will, the camera was able to gather enough power every 35 minutes to capture an image. While clearly not enough to go to market, it does represent an exciting step forward in terms of the IoT. 

“The ability to deliver power wirelessly to a wide range of autonomous devices and sensors is hugely significant,” said a story about the research in MIT's Technology Review. “PoWi-Fi could be the enabling technology that finally brings the internet of things to life.”

Review Mr. Talla and his colleague’s paper on the technology for free here: Powering the Next Billion Devices with Wi-Fi.

Via BBC