With a clever bit of science, Japanese researchers have developed a gadget that turns sound waves into electrical energy.
This one is a bit heavy on the tech jargon, so hold on to your butts. Courtesy DigInfo:
[The device] consists of a piezoelectric element to produce the sound waves, a magnetic material to generate a spin current, and a three-layered metal structure to detect the spin current. By producing the sound waves, we inject a spin current from the magnetic material into the metal layers. And by using a phenomenon called the reverse spin Hall effect in the metal, we convert the spin current to an electrical voltage. In this research, we detected the spin current by measuring the voltage.
Did you catch all that? In layman's terms, the researchers (Professor Eiji Saito of Tohoku University and researchers from Japan's Atomic Energy Agency) used sound to vibrate a metal structure. This vibration causes a current to transfer from the magnetic layer to the metal layers. Then, via the "reverse spin Hall effect," said current is transformed into useful electrical voltage.
Admittedly, the relative amount of voltage generated here is rather small. More than anything, this experiment is a proof of concept for the idea that sound itself can be harnessed for electrical energy generation.
Currently, Professor Saito's team is looking into a range of other materials to see just how much voltage each might generate within this device.
I like the idea of capturing sound energy to generate useful electricity -- step out onto the corner of a busy street if you ever want an example of how much excess sound energy we have bouncing around -- but nowhere in this news does anyone ever discuss the efficiency of the process. It takes energy to generate sound, and unless Saito is a wizard, his tech likely doesn't generate electricity at 100% efficiency (for reasons too numerous to get into here).
However, assuming it can be properly scaled, I could see this technology functioning as a sort of "sound gutter" that catches excess noise that would otherwise drift into the ether and instead does something useful with it. Those vibrations were just going to ricochet out into space, so we may as well put them to work.
It's about time these lazy, freeloading sound waves started pulling their weight around here.