The Feynman Companion

USB Cameras on Linux, Explained From First Principles

"What I cannot create, I do not understand."

— Richard Feynman

A layer-by-layer journey through 4 USB cameras, an industrial computer,

a hub, and all the beautiful complexity in between.

Before We Begin: How to Read This

Feynman had a trick. When he wanted to understand something, he didn’t start by reading the textbook. He’d ask: “What’s the simplest version of this problem I can actually picture in my head?” Then he’d build up from there, adding one complication at a time, never moving on until the current piece felt obvious.

That’s what we’re going to do with this USB camera system. We have four cameras plugged into an industrial computer. Two go straight into the machine, two go through a little box called a hub. Every camera can take a 48 megapixel photograph. Sounds simple. It isn’t. By the time we’re done, you’ll understand why—from the electrons on the wire all the way up to the software that stitches the images together.

Each chapter is one layer. Each layer has analogies to build your intuition, chalkboard boxes for the hard facts, and traps to warn you where smart people get fooled. Let’s go.

Chapter 1: The Wire and the Silicon