Wireless power transmission via Wi-Fi signals to a security camera has been achieved by American researchers. Wireless power transmission may sound dangerous and futuristic, but it could determine how the Internet of Things will evolve. Researchers from the University of Washington have managed to charge the JawBone UP24 fitness tracker using Wi-Fi.
They noticed that the WiFi that has flooded our environment is capable of charging a variety of tiny devices, but only for randomly short intervals. To address this problem, they transmitted noise over the WiFi, along with the signal, to keep the levels of energy being transmitted at a constant level, but without affecting the data transmission.
The team found that the energy contained in the ubiquitous Wi-Fi signals often reached the voltages required by many low-power devices. However, their periodicity posed a problem, as they are emitted at different frequencies. According to reports in MIT Technology Review and the BBC, the camera had been modified so that it could harvest energy from existing Wi-Fi signals in its surroundings, store it, and then use it to take pictures.
The experiment was one among others by American researchers looking for ways to use Wi-Fi as an energy source, while the team behind this particular technique believes that it will be particularly useful in the context of the "Internet of Things".
The system, known as power-over-wi-fi, was developed by Vamsi Tala, a doctoral student, and colleagues at the Sensor Systems Lab at the University of Washington in Seattle. Using this technique, called PoWi-Fi, they were able to transmit power to a low-power security camera and a temperature sensor from a distance of 6 meters.
To address this problem, the team modified hotspots and routers so that they produce "noise" when a channel is not being used for data transmission.
This means that the signal strength remains stable and, although low, is high enough to power some components. Also, the noise generation had minimal impact on data rates.
The system was used to operate a temperature sensor and a small camera several meters away from a Wi-Fi hotspot.
The camera collected enough energy from Wi-Fi and stored it in a transformer that made it take photos when it was fully charged. Therefore, it was able to collect enough energy to take a photo every 35 minutes.
Because these results did not leave them completely satisfied, they tried other options. They added a rechargeable battery to the camera and thus managed to provide sufficient power for the camera from a distance of up to 7 meters, even when the signal passed through a wall.
They also tested this setup in 6 different homes and found that the modified routers did not cause any problems with data transmission speed. Finally, they managed to charge the JawBone UP24 fitness tracker using PoWi-Fi to 41% in 2.5 hours. Undoubtedly, these results are extremely impressive and promising.
