November 16, 2025
Relays, rage & retro vibes
A 1961 Relay Computer Running in the Browser
Watch a 1961 relay computer think slowly — and the comments go wild
TLDR: A faithful browser simulation of Claude Shannon’s 1961 Minivac 601 lets you watch a relay computer count in real time. Commenters argue over history accuracy (add vacuum tubes!), debate “inventor” credit, and crack jokes about retro haptics—making slow computing weirdly thrilling and surprisingly educational.
A browser-based recreation of the 1961 Minivac 601 lets you literally watch a relay computer “think” one click at a time—and the community lit up like its blinking lights. Some went full history cop: one commenter insisted the description “Before microchips, relays” should also shout out old-school vacuum tubes. Others were here for the vibes. One fan cackled that wiring up the rotary switch feels like real-life haptic feedback, like a retro fidget spinner with homework. Nostalgia hit hard too, with RadioShack kit memories and a manual that apparently includes games—yes, grandma’s computer could play.
The project’s maker jumped in, giving credit where it’s due and revealing the secret sauce: Willy McAllister’s Circuit Sandbox powers the electrical math. Translation: this isn’t just a skin on a page; it’s a simulation that behaves like the real relay beast. Cue the philosophical brawl: is calling Claude Shannon the “inventor” fair? One commenter argued heroes are overrated and breakthroughs are incremental, dropping a hot take that stirred the hive. And then there’s the cynic who joked it’s easier to build the simulator than make it do anything cool.
Bottom line: it’s slow, blinky, wonderfully tactile, and the crowd is split between playful nostalgia, history nitpicks, and big-picture inventor debates. Also, you can make a “short circuit” safely. Rock on, chaos.
Key Points
- •A browser-based simulation replicates the 1961 Minivac 601, an educational relay computer.
- •The simulation showcases a simple 3-bit binary counter with lights 4, 5, and 6 counting from 0 to 7 in binary.
- •Users can build circuits in an interactive Simulator by dragging wires and connecting components.
- •Short circuits can be created safely within the Simulator environment.
- •The site provides original Minivac manuals and errata, and notes the project is a work in progress.