Printing Crazy Typewriter Art with the IBM Selectric’s Weird “Golf Ball”

IBM’s Selectric range of typewriters were legitimately useful machines when they were new in the 1960s, but today they’re mostly known for their weird typing element — the bit with all the embossed characters that resembles a golf ball. Unnecessary Automation used that “golf ball” to build this crazy machine that automatically produces ASCII art-style prints.

This machine doesn’t keep much of the original IBM Selectric. It really only retains that golf ball typing element and the ink ribbon. Everything else is custom-designed and fabricated for this project.

The biggest challenge was actuating the golf ball, which required orienting the desired character forward and hammering the entire thing against the paper to transfer ink. The mechanism to achieve that has three degrees of freedom: one to rotate the ball, one to tilt the ball, and one to swing the ball at the paper.

In addition to the motors needed for the ball movement, there are motors to feed the paper, to move the paper carriage, and to feed the ink ribbon.

Unnecessary Automation doesn’t provide detail on the control hardware, but we can see in the video that the software says “Scanning for Arduino.” It isn’t clear if there is an actual Arduino board, or just a microcontroller programmed with the Arduino IDE.

Either way, Unnecessary Automation started by creating a simple CLI that would reproduce any entered text on the machine, almost like a paper terminal with echo turned on. He then expanded that with algorithms that use Fourier Transform processes to turn images into something like ASCII art. Except there is one big difference: the machine can overlap characters as much as it wants.

The result is surprisingly high-fidelity monochrome printing combined with satisfying Selectric clacking.