No-power Wi-Fi connectivity could fuel Internet of Things realityResearchers at the University of Washington have devised a way for battery-free devices to skim a connective link from errant WiFi signals, potentially increasing the reach of the Internet of Things to include just about any thing. The new tool, called a backscatter, looks like a thin plate of metal that works by “looking” for WiFi signals moving between the router and a laptop or smartphone.
They encode data by either reflecting or not reflecting the Wi-Fi router’s signals, slightly changing the wireless signal. Wi-Fi-enabled devices like laptops and smartphones would detect these minute changes and receive data from the tag. In this way, your [battery-free] smart watch could download emails or offload your workout data onto a Google spreadsheet.