Computer engineers at the University of Washington have developed a new Passive Wi-Fi system that is able to maintain fast data speeds while consuming one 10,000th of the power of conventional wi-fi and one 1,000th of the power of current energy-efficient technologies like Bluetooth Low Energy.

This was accomplished by taking  the power-hungry analogue elements of wi-fi, which are mostly needed to produce signals at the right frequency, and housing them in a single device which is plugged into a wall. This produces signals which are picked up and relayed by a range of passive devices using almost no power.

Instead of multiple, battery or mains-powered devices all receiving and sending signals in sequence, most elements of the network are able to operate without needing a battery – the little power that they do need can be harvested from the wi-fi signals that the central unit is backscattering, or by feeding on other signals such as TV and radio broadcasts.

The researchers believe that tiny Passive Wi-Fi devices could be extremely cheap to make – possibly costing less than a dollar.

The technology is being developed commercially by Jeeva Wireless.