Ambient backscatter

An interesting article on how to power sensors and other "Internet of Things" devices.

A group at the University of Washington has developed a way of making use of "stray" radiation to power simple radio transmitters and receivers. Rather than use a dedicated power source, whether on-board like a battery or transmitted as in near-field communications, this technique makes use of the ambient radiation of cellphone signals, wifi networks and the like to provide enough power to energise a simple radio link.

Recycled Energy: Ambient Backscatter Allows Wireless Communications with no Batteries

If it works reliably, this'll be a huge contribution to low-power environmental sensing as well as to the applications the authors are targeting.