Scientists from ETH Zurich have developed a battery-free sensor that responds to sound waves. The study was published in the scientific journal magazine Advanced Functional Materials (AFM).
“The sensor works completely mechanically and does not require an external power source. It simply uses the vibration energy contained in sound waves,” explained Johan Robertsson, one of the co-authors of the invention.
The device consists of a silicon-based metamaterial. Its properties are associated with a special structure. Using computer simulations and algorithms, the researchers created a series of identical resonator plates connected by small rods. They act like compressed springs under the influence of sound waves of a certain force.
The sensor’s vibrations produce tiny electrical pulses that excite its electronic components.
The researchers think their battery-free, voice-activated design has many potential applications. It can be used to monitor earthquakes and buildings, for example to detect specific sound coming from cracks in a building’s foundation. Or it can detect the hissing sound caused by gas leakage and trigger the alarm.
The device can also be used in medicine, equipped with hearing implants and used for continuous measurement of eye pressure.
Scientists aim to launch the solid-state prototype of the sensor by 2027. New versions should be able to distinguish up to 12 different words, including standard commands such as “on,” “off,” “up” and “down.” Compared to the palm-sized prototype, engineers plan for new versions to be fingernail-sized or smaller.
Previous scientists was created Transparent flexible implant for reading brain activity.