This isn't the first time we've come across a development claiming to have created the world's smallest musical instrument, but the catch is that its sounds are often beyond what the human ear can register. After all, what's the point of a musical instrument that can't be heard? The Micronium manages to avoid this trap by generating up to six different tones with "strings" that move barely a few micrometers.
The first problem: hearing it
Imagine a violin. A wonderful instrument if ever there was one, demanding talent and experience not only to play it, but also to build it. Now, start shrinking its size to the point that you need a microscope. What sense does such a violin have? How would you play it? The truth is, the first problem is hearing it. In 1999, Cornell University created a "nano-harp" whose strings were no more than 50 nanometers thick, but its frequencies were too high. And it took until 2010 for the University of Twente to shape the Micronium, the first "nano-violin". The instrument had a public demonstration at the time, which we can appreciate in the following video, near the four-minute mark:
How it works
Basically, it's a group of masses (or weights), no more than 12 millionths of a gram, suspended on springs. The masses are set in motion by a system of "combs", generating vibrations with movements of a few micrometers. That's more than enough to create a tone, which depends on how deep the displacement was. A Micronium chip can hold a total of six "string" systems or tones, but the idea is to combine several chips and increase their number.
Not as simple as it sounds
Of course, this sounds much simpler than it actually is. The tones need to be amplified (ten thousand times the resonator movement), and the whole system requires a vacuum chamber, allowing the possibility of modifying the length of the notes if the pressure is changed. If my ears don't deceive me, I think at one point in the demo they play the music from "The A-Team"...
