Researchers conceive method to power a camera via Wi-Fi. RF energy harvesting is gaining traction in various applications in 2015.
Last month we stumbled over this geek mind blowing technology of harvesting energy from radio frequencies. We reported about the K3Ops smartphone case that recharges a smartphone from stray radio frequencies transmitted by Wi-Fi and other sources. There is also Nikola Labs that wants to extend smartphone battery life by harvesting stray RF waves emanating from the smartphone.
Now a group of researchers lead by Vamsi Talla at the University of Washington in Seattle issued a paper detailing their research in using Wi-Fi routers powering a Surveillance Camera. This concept intentionally sends power to an electronic device. They reprogrammed three Atheros AR9580 chipset found in Wi-Fi routers to transmit also when they are not sending data.
The researchers have been able to supply a low-power Omnivision VGA sensor capable of producing 174 x 144 pixel black and white images, which requires 10.4 milliJoules of energy per picture.
To store energy, they attached a low leakage capacitor to the camera, which activates when the capacitor is charged to 3.1V and continues operating until the voltage drops to 2.4 Volts. The images were stored in a 64 KB non-volatile ferroelectric random access memory.
“The battery-free camera can operate up to [about five meters] from the router, with an image capture every 35 minutes,” say Talla and co. By adding a rechargeable battery they increased that 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.
Is RF energy harvesting the power source of IoT? There is certainly a lot of potential. Batteries are still a pain and running cables to sensors is a pain too. Sending power through Wi-Fi routers would be very convenient. The research was published in the Cornell University Library. Via MIT Technology Review.
