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Scientists Use Wi-Fi Signals To Power Camera Without Battery

A research team at the University of Washington in Seattle has developed a new wireless charging system called ‘Power Over Wi-Fi’ (PoWi-Fi) system which has the capability to recharge batteries through the air, from a distance of up to 28 feet. Scientists, including one of the Indian-origin, have used Wi-Fi signals to power a battery-free camera five meters away, an advance that brings the idea of Internet of things closer to reality.

The idea is simple in concept and it is developed by doctoral student Vamsi Talla and colleagues. Wi-Fi radio broadcasts are a form of energy that a simple antenna can pick up. Click here for best spy checker internet tips. Vamsi Talla simply connected an antenna to a temperature sensor, placed it close to a Wi-Fi router and measured the resulting voltages in the device and for how long it can operate on the remote power source alone. Even more ambitiously, the team also connected a camera to their antenna.

Wi-Fi broadcasts are not continuous. Routers tend to broadcast on a single channel in bursts. This provides enough power for the sensor but as soon as the broadcast stops, the voltages drop. To store energy, they attached a low leakage capacitor to the camera which activates when the capacitor is charged and continues operating until the voltage drops to 2.4 Volts. The images were stored in a 64 KB random access memory (RAM). In the subsequent tests, the camera performed remarkably well.

“The battery-free camera can operate up to [about five meters] from the router, with an image capture every 35 minutes,” researchers said. By adding a rechargeable battery, he increased the distance to seven meters. The router could even power the camera through a brick wall, demonstrating that it would be possible to attach the device outside while keeping the power supply inside.

The team also connected their antenna to a Jawbone fitness tracker and used it to recharge the battery that powered it. “Using this, we charge a Jawbone device in the vicinity of the power-over-Wi-Fi router from a no-charge state to 41 percent charged state in 2.5 hours,” the team pointed out.

During tests, researchers were able to recharge a camera, some rechargeable batteries, and temperature sensors. The distances from where the devices received the power signal and connected to the router varied, from 28 feet for the batteries to 17 feet for the camera.

According to the researchers, the access point (a router) is capable of achieving ‘power over Wi-Fi’ in such a way that it can work with pre-existing hardware and does not cause any interference to the users’ Internet connection. Researchers plan to expand their technology and make it available on a larger scale.

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