The micronium is a musical instrument with strings a millionth of an inch thick, and thanks to some nifty engineering it's the tiniest instrument ever producing audible notes. This really is the world's tiniest violin, but it's playing for everybody.
Previous attempts at building a micronium resulted in instruments that could only create tones inaudible to humans, which detracts a bit from the idea of a musical nano-instrument. This new device, the invention of the MESA+ Institute for Nanotechnology of the University of Twente in The Netherlands, is able to produce six different tones, all of which are audible when properly amplified. They accomplish this through an ingenious system of tiny weights.
The tiny strings, each about a micrometer thick, are anywhere from half to one millimeter. On the strings, the designers placed several tiny weights, each about a dozen micrograms in mass. The masses are then put into motion by tiny interlocking combs that shift around in relation to each other. The mass vibrates and shifts a few micrometers in either direction. It's not much, but it's enough to create a specific tone depending on the amount of displacement. Any one micronium chip can fit six string systems on it, although combining several chips can create a wider variety of tones.
Designer Johan Engelen admits the hardest part of the project was properly tuning the micronium to produce the desired tones. A composition has been specifically written for the micronium, "Impromptu No. 1 for Micronium" by Arvid Jense. The composition debuted this past Sunday at the Atak music venue in Enschede, site of a conference on micromechanics. You can see a video of their presentation, including a demonstration of some of the tones the micronium can create around the 6:00 mark, below.