Here's a clever, artistic hack: Taking a dot-matrix printer and using its mechanism to tap a pencil against paper — slowly drawing out a picture as a series of tiny graphite dots.
As Hackaday notes:
The software converts the image into an array, with 0 representing white and 1 representing black. The printer itself works a bit like an old-school CRT TV: the scanner array moves the printer along a horizontal line, then moves it vertically and along another horizontal line. It then triggers the hard drive actuator to create a mark on the paper if there is a 1 in the array at that point.
I love artbots that employ physical techniques humans not only wouldn't use, but probably couldn't: It'd be pretty hard for a mere mortal to tap a pencil so accurately, for so long. When the camera zooms in on that video you can see the eerie results this robot achieves — the freaky sheen of graphite produced by a zillion little taps.
It also reminds me how fantastically rugged and reliable were those old dot-matrix printers. I used a couple back in the late 80s at a campus newspaper, and then in the early 90s when I was working as the receptionist at a driving school in Toronto. They were as noisy as a tommy gun, but tough as old boots: I could run 'em for hours and never have a problem. In contrast, today's printers are Rube Goldberg devices so wildly fragile that they break if you look at them in the wrong way; if you think about them in the wrong way, it sometimes feels. "The state of networking in the printer industry is abysmal," as The Wirecutter put it — in a piece called "Why All Printers Suck" — which concludes: "Basically, printers are a dismal product category."