Affordable personal computers weren’t commonplace until the 1980s — and even then, the term “affordable” is relative. But budding computer scientists and users still needed a way to learn basic computing principles in the decades leading up to that. If you were lucky, your university might have had a computer you could use. Everyone else had to make do with educational toy computers. Those could be used to teach the fundamentals of computing, but weren’t actual computers. One of the most iconic examples was the GENIAC (GENIus Almost-automatic Computer), and now you can follow Megardi’s tutorial to build your own.
The GENIAC, designed by Edmund C. Berkeley, was originally released in 1955 and was sold through the ’60s. Computers of that era were massive and incredibly expensive, but the $15.95 ($152 today) GENIAC could reproduce some of the basic Boolean logic of a computer using simple parts. The GENIAC design consists of a base board with six perforated disks. Users would manually wire connection points between a battery, those disks, and output light bulbs. By turning the disks to specific positions, an electrical connection would be formed that follows a path dependent on the setup. It could be used for very simple operations like addition, and even more complex tasks like converting binary to decimal.
Creating your own is quite straightforward if you understand how the GENIAC operates. You can use a laser cutter or CNC router to fabricate the base board and discs — or cut them yourself by hand. Then you only need a battery and holder, some light bulbs, and wire jumpers. Megardi has 3D-printed mechanical parts to make the construction easier, but there are many ways you can craft those. If you’re feeling particularly inspired, you could build Megardi’s “GENIAC Redux.” It follows the same basic logic, but utilizes modern and inexpensive components to improve how reliably the system works.