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I’m building a computer. Not assembling one from parts with a screwdriver — 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.
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 understand — 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 and I have already, in log one, wired a chip in backwards. It got warm. We learned.
More soon.
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