Sensors have been developed that charge from conversations around them (2 photos)

Researchers from the Robertson Laboratory at the Zurich Swiss Innovation Park in Dübendorf have come up with sound sensors that get their energy from nearby conversations.

The sensor consists of dozens of identicalstructured plates connected to each other by tiny rods that act like springs. It is the springs that determine whether a particular sound source drives the sensor. Whenever a certain word is spoken or a certain tone or noise is generated, the sound waves emitted - and only those - cause the sensor to vibrate. This energy is enough to generate a tiny electrical pulse that turns on an electronic device.

There are a huge number of sensors in the mostvarious areas requiring constant nutrition. Their energy usually comes from batteries, which are not always easy to get to if they run out. And there are about 78 million used batteries every day, all of which are toxic waste. Sound sensors could replace them.

In addition, they can be used for monitoringearthquakes or oil wells. Researchers aim to release a solid-state prototype of the sensor by 2027: the new version will not only be powered by sound, but also distinguish up to 12 different words.