If there’s one category among those we see here at Hackaday that has everything from relay-based machines that fill a wall through to modern machines with a retro twist, there must be few of us who haven’t seen such a project as been impressed. Our most recent contest challenged you to come out with your best retrocomputing projects, and we’re extremely pleased to say that you didn’t disappoint us. Here are the results, both the outright winners, and the honourable mentions.
First up, our top three. For these, we are happy to award the prize of a $150 DigiKey gift certificate.
A Vacuum Tube Computer
The Tiny Sieve implements a Lehmer sieve with 30 ATtiny412 microcontrollers replacing those bicycle chains or delay lines, with an RP2040 performing the task of controller. This reflects in a curious way the delay line sieve of the 1960s, where the controller task was performed by an IBM minicomputer passing a paper tape to the machine. Its results are comparable to those in the paper describing the bicycle chain sieve so perhaps it’s not the fastest, but it works.
This project is special on many levels, impressing the judges because of its unusual subjkect, and its explanation of this niche in mathematical and computing history. We may never need one, but now at least we’ve seen one and know how it works.
Honorable Mentions
The quality and breadth of the entries to this contest was a joy to read through, and it’s sad that we had only three prizes to award. We came up with a set of categories for the competition, and here follows just a small selection of the ones which caught our eye.
Retro-Modern
This category was for old hardware doing something much newer. Can your 8-bit micro compete in 2026? Here was its time to shine!
