ROS 2 Foundations: Nodes, Frames, and Robot Vision
You can structure a robot as ROS 2 nodes, choose topics against services and actions correctly, and place a camera's observations in the robot's frame tree.
Everything else on this site runs on a microcontroller: one program, one loop, total control. ROS 2 is what you move to when a robot outgrows that—when it has a camera and a planner and a driver stack that all need to run at once, written by different people, restartable independently.
The price is a new set of ideas, and the first is that a ROS 2 robot is not a program but a graph of nodes talking to each other. Most of the early confusion is choosing wrong between the four ways they can talk, so that is where this path starts: topics for streams, services for quick requests, actions for long jobs you might need to cancel.
Then TF2, which is the part that quietly defeats people. A robot is a tree of coordinate frames—the base, the wheels, every sensor—and almost every real bug is a transform that is missing, stale, or attached to the wrong parent. Once frames make sense, a calibrated camera becomes just another node publishing a pose into that tree, which is exactly how vision joins the rest of the robot.
Learning roadmap
The path
Follow the nodes in order—each unlocks the next once you have done it. Your progress saves on this device.
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