The trouble with microphones is that they don’t just hear — they have to listen. Powering the mic and its signal processor means using energy, and energy means a battery, and a battery means charging. This new microphone-like system hears more like the way our own ears do, requiring little or no power, and could help fill the world with voice-responsive machines. (If that’s something we really want.)
The device is called a “triboelectric auditory sensor,” and it works via what’s called the triboelectric effect — essentially when two surfaces rub together and create a charge. They’re still trying to figure out why this happens, but what matters to engineers is that it happens reliably.
Triboelectric nanogenerators have been around for a few years, creating power by having two compatible materials interact with each other at super-small scales. While they’re tiny and highly efficient, they don’t actually produce a lot of power. Researchers from Chongqing University found that, fortunately, you don’t need a lot of power for the purposes of detecting sound.
