In the 1960s, the home computer was barely a twinkle in anyone’s eye. This was the decade in which computers were used by a handful of companies and organizations and took up entire rooms. It was the decade that saw the birth of the first integrated-circuit computer, the Apollo Guidance Computer, and, rather strangely, one of the first home computers of sorts: the Digi-Comp 1.

In 1963, E.S.R. introduced this little programmable educational toy computer. It relies on simple mechanical logic gates, programmed by positioning tubes on sliders. Their original intention was to create actual computers, but one thing led to the next, and E.S.R. became the premier educational computer toy company of the 1960s. The Digi-comp is a rather simple device. A program is entered by soda-straw-like tubes placed on sliding rails. These tubes interact with spring-loaded levers which move in accordance with the “clock” switch. The result is a simple binary computer you can program.

[Chris Staecker] got a remarkably well-preserved Digi-Comp I to demonstrate its unique functioning. With some rubber bands and a touch of modern technology in the form of 3D printing, [Staecker] got the toy working like new. The programming process is quite manual, and its functioning is not obvious. But it can compute binary outputs of given functions. Unfortunately, this is not a Turing-complete process, but rather a state machine with 8⁸ (or 16,777,216) possible states. The toy, with all its limitations, is highly reflective of the state of computing at the time, and a rather neat look at what the future was, back in 1963.

Make sure to take a look at E.S.R.’s successor to the Digi-Comp I, the creatively named and quite different Digi-Comp II. We’ve looked at other old “sort of” computers like the Geniac. You can even simulate that one in your browser.