Swiss scientists create sensor powered by energy from sound vibrations

Scientists from the Swiss Federal Institute of Technology (ETH) in Zurich have developed a sensor that operates without batteries and responds to sound waves. The research has been published in the scientific journal Advanced Functional Materials.

"The sensor works purely mechanically and does not require an external power source. It simply harnesses the vibrational energy present in sound waves," explained one of the co-authors of the invention, Johan Robertsson.

The device is constructed from a silicon-based metamaterial whose properties are linked to its unique structure. Using computer modeling and algorithms, researchers created a grid of identical plate resonators connected by tiny rods. These elements act like springs, compressing under the force of specific sound waves. The sensor's vibrations generate small electrical pulses, activating its electronic components.

The researchers envision numerous potential applications for their battery-free sensor powered by sound. It can be used for earthquake and building monitoring, detecting, for instance, specific sounds emanating from cracks in a building's foundation. Alternatively, it could identify gas leakage sounds and trigger an alert. Moreover, the device could find use in medicine, powering hearing implants and continuously measuring eye pressure.

Scientists aim to release a solid-state prototype of the sensor by 2027. The new versions should be capable of distinguishing up to 12 different words, including standard commands such as "on," "off," "up," and "down." Compared to the palm-sized prototype, engineers plan for the new versions to be the size of a fingernail or even smaller.