Wireless Communication without Power Consumption
An easy way to extend the battery life of devices like smartphones is to turn off their wireless radios. Broadcasting signals is an energy expensive process, which is one of the reasons we have not yet achieved an Internet of Things that will connect non-traditional devices. Researchers at the University of Washington though have developed a technology that drops the energy required for wireless data transfer to negligible levels by taking advantage of the signals already there.
Traditional wireless communication relies on a transmitter to put out a signal for a receiver to pick up. Previous research has demonstrated that the energy of those signals can be captured and used to power some small devices, but typically the power acquired this way is not enough to send a signal. The Washington researchers solved this problem by not sending signals but by using Wi-Fi backscatter, which alters signals already in the air, instead of producing new ones. Doing this is so much simpler that the device using this technology would not need a battery to communicate.
So far the researchers have demonstrated communication at 1 Kbps with a two meter distance between devices, which they hope to increase to 20 meters. While that is a relatively slow connection, the idea here is not to download webpages and videos but to provide simpler data, like temperature information on a room or your workout statistics to an online spreadsheet.
Source: University of Washington