Michael Gardi Brings Back the 1968 "Paperclip Computer" in 3D-Printed Form

Tinkerer Michael Gardi has succeeded in recreating — and, in some ways, improving upon — the classic 1968 "paperclip computer," releasing a series of 3D-printed part files for anyone wishing to build their own.

"I recently came across a book published in 1968 entitled How to Build a Working Digital Computer by Edward Alcosser, James P. Phillips, and Allen M. Wolk," Michael Gardi writes. "Believers in the 'learn by doing' philosophy, they show how to construct such a computer using 'simple inexpensive components usually found around the house or in a neighbourhood electrical parts store.' This is often called the 'paperclip computer' book since they use paperclips to create switches throughout the design.

"There have been a few implementations based on the book over the years. This project will document my efforts to make my own version of a 'Working Digital Computer' henceforth to be called WDC-1. My intent is to use period technologies but modern building techniques like 3D printing and PCB fabrication. I will probably not use paperclips for switches."

Since launching into the project, Gardi has progressed through to a completely functional WDC-1 — and, as promised, paperclips do not feature. Impressively, Gardi has documented each stage of the process both as it appears in the book and as his interpretation — which leans heavily on 3D printing of components, rather than the use of wood and household junk of the original design.

While many of the designs that have resulted from the project - such as the decimal to binary encoder, the first module described in the book - are likely of little use to anyone not looking to build a vintage computer, others have more generalised potential.

"I am going to need about 86 console lights for this project. I'm also trying for a 'vintage' look," Gardi writes of one such sub-project, 3D-printed panel-mount LED sockets now available on Thingiverse. "So I came up with these based on the panel lights from the GENIAC computer. These are really inexpensive to make, a few cents each. The cheapest I could find on Digi-Key was about 50 cents."

Gardi's build progresses step-by-step through the encoder, front panel, core memory, drum memory, and all the control switches and lights required from the original design — plus a binary to binary coded decimal (BCD) converter, which was not part of the original design and which Gardi opted to build from an Arduino Nano for simplicity's sake. Finally, Gardi wrote a few programs - including one which calculates a Fibonacci sequence — to prove his creation's functionality.

The full project logs are available on Gardi's Hackaday page.