New wireless devices communicate without batteries.
University of Washington Engineers have developed wireless transmitters and receivers which are able to communicate over short distances without an in-built energy source.
Instead of a battery, the devices use a technique known as ‘ambient backscatter’, where they detect, harness, and reflect TV signals to create a sort of “morse code” which can transmit small amounts of data between the devices.
During testing the devices were used in a variety of indoor and outdoor locations around Seattle, and successfully communicated with each other at distances of up to 2.5 feet at 1 kilobit per second. That’s enough to send information such as a sensor readings, text messages and contact information.
Potential uses for the devices include allowing wearable devices such as smartwatches to send text messages or emails without power, or as a secondary method of communication when their batteries run out. It could also allow battery-free wireless sensor networks, for example, sensors placed in a bridge could monitor the health of the concrete and steel, then send an alert if one of the sensors picks up a hairline crack.