Powering smart devices with Wi-Fi

New Scientist : To clean up the mess of wires and chargers currently required to recharge our numerous gadgets, researchers in Seattle are experimenting with a wireless technology that draws electrical current from a household’s Wi-Fi. Vamsi Talla from the University of Washington and colleagues modified electrical devices in six Seattle homes so that they were powered solely by the Wi-Fi router signal. They used a component called a rectifier to convert the router’s radio waves into direct current and then boosted the voltage using a DC–DC converter. The drawback is that Wi-Fi signals are not very powerful and are only active when someone is browsing the Web. However, by using software to force the router to constantly emit a signal, the researchers have successfully demonstrated that their system can power temperature and camera sensors, recharge batteries, and perform other similar tasks.