Well, this wins points for creativity. Computer scientist Chris Gregg of Tufts University decided he wanted to turn his vintage, 1960s Smith Corona electric typewriter into a printer. It turned out to be quite a bit more work than he bargained for, but the resultant invention is marvellous.
When Gregg purchased the typewriter, he had hoped to find a way to drive the key switches directly with his computer. This, however, ended up being impossible, as the switches were not electronic at all, but in rather, driven by a complex mechanical system. The project fell to the wayside for a couple of years, but was reignited this spring, when a friend of Gregg's suggested he use miniature electromagnets called solenoids to drive the keys instead.
Dozens of hours of design, wiring and debugging later, Gregg had himself a custom solenoid array that fits directly over the typewriter's keyboard. This array takes commands from an Arduino Uno, which in turn is fed data through an OS application, allowing a user to 'print' directly from a MacBook.
To demonstrate just how cool his creation is, Gregg naturally decided to have it play percussion for Leroy Anderson's "Typewriter Symphony." The composition includes a part written specifically for typewriter, although we're not sure it's ever been performed autonomously before -- and with a typewriter printing actual words, to boot.
I love that people like Gregg are finding interesting ways to repurpose forgotten technology. If you want to build your own typewriter printer, you can read much more about the process over on Gregg's website.