Radio waves power tiny temperature sensor

The internet of things has already begun to fill our homes with smart appliances and sensors. Powering these new devices in a cordless and clutter free way has been a limiting factor in their adoption.

To help limit countless cords, a researcher at Eindhoven University of Technology (TU/e) named Hao Gao has developed a temperature sensor powered by radio waves.

Gao designed the sensor to require very little electricity so that it could be powered wirelessly eliminating the need for either batteries or cords. It works by absorbing the energy from radio waves which are emitted from a special router. The sensor uses its stored energy to transmit a signal back to the router. As the temperature of the sensor flucutates so does the frequency of the signal. The router is then able to decode the signal to detect the temperature where the sensor is placed.

The sensor, which is based on 65 nanometer CMOS technology, was designed to be small enough that it could be hidden out of sight in buildings and homes. It is just 2 square millimeters in size and weights only 1.6 milligrams. The range of the current verion of the sensor is 2.5 centimeters but TU/e is hoping that it can exend the range to 1 meter in a years time with the final goal being a range of 5 meters.

It costs 20 cents to produce the wireless sensor making it a cost effective way to allow devices to communicate with one another.

Image Source: Shutterstock / nevodka