It was the 1960′s, and people were building some very
interesting digital computers. One of them was the Digi-Comp II,
which we have written about extensively: a binary mechanical
computer based on rolling marbles and flip-flop gates. For an
entirely different approach, look no further than How to Build a
Working Digital Computer (1967) by Edward Alcosser, James P.
Phillips, and Allen M. Wolk. You can download it as a free
e-book (PDF, EPUB, Kindle) at Archive.org, thanks to the
BitSavers PDF Document archive. How to Build a Working Digital
Computer is both an introduction to the “new and exciting field
of digital computers” and a set of plans to build one. What’s
especially interesting is that the plans don’t call for any
specialized electronic components, but instead show how to build
everything from parts that you might find at a hardware store:
items like paper clips, little light bulbs, thread spools, wire,
screws, and switches (that can optionally be made from paper
clips). That’s not to say that such a