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I’m building a computer. Not assembling one from parts with a screwdriver, but building one from logic chips and wire, on breadboards, following Ben Eater’s legendary project series.
If you haven’t seen his stuff: Ben Eater makes videos where he builds a working 8-bit computer entirely out of basic components on breadboards, explaining every single wire. No microcontroller doing the magic behind a curtain. Just logic gates, registers, and a clock, the actual guts of how a computer thinks.
Where I’m starting: the clock
Everything in a computer marches to a clock, a steady pulse that says “now, now, now” and keeps every part in step. So that’s project one: build a clock module that can run at an adjustable speed, and also step one pulse at a time so you can watch the machine think in slow motion.
It’s built around the 555 timer chip (the little workhorse that’s been in everything since the 70s) plus a 556 and some logic to let you switch between automatic and manual stepping. I’ll be putting together some pictures soon (maybe even a video when I get it working). One interesting thing I have found while building this is all the components (capacitors, usually) that are there to reduce noise in the circuit. In the past, circuits I built were pretty easy to understand: you follow the wire and it lights the light. But now, the 555 timer chip documentation specifically says how to reduce noise by using specific capacitors. It’s made me realize that you really can just track back every component to why it’s there.
Why do this in 2026, when a $5 chip does it better?
Because a $5 chip is a black box. This isn’t. When I’m done, I will really understand, in my hands and not just in theory, how a computer goes from “electricity” to “running a program.” That’s the whole point of this blog: build the thing yourself so it stops being magic.
The plan
- The clock module ← I’m here
- Registers and the bus
- The arithmetic unit (making it add)
- RAM
- Program counter
- Control logic (the part that ties it all together)
- Watch it run an actual program
I’ll log each stage here, mistakes and all. And there will be mistakes. Breadboard wiring is fiddly.
More soon.