ROS is the closest thing robotics has to a universal language. It lets the sensors, motors, cameras and brains of your robot pass messages to each other in a clean, standardised way — so you spend less time writing glue code and more time actually building robots.
What is ROS?
ROS stands for Robot Operating System, though it isn’t really an operating system in the traditional sense. It’s a middleware framework — a layer that sits on top of Linux and gives robot components a common way to communicate.
The current version is ROS 2, a complete rewrite that fixes many limitations of the original. It runs on Ubuntu and other Linux systems, and increasingly on Raspberry Pi hardware too.
At its heart, ROS 2 uses a publish/subscribe model. A node that reads a LIDAR sensor publishes distance data to a topic. Another node subscribes to that topic and uses the data to avoid obstacles. The two nodes never need to know anything about each other — they just pass messages. This makes it easy to swap out components, test individual parts, and reuse code across different robots.
Here’s that idea drawn out. Each box is a node (a small program); the arrows carry messages over named topics. The nodes never talk directly — they only ever publish to, or subscribe from, a topic:
flowchart LR
LIDAR["LiDAR node"] -->|"publishes /scan"| SCAN(("/scan"))
SCAN -->|"subscribes"| NAV["Navigation node"]
CAM["Camera node"] -->|"publishes /image"| IMG(("/image"))
IMG -->|"subscribes"| NAV
NAV -->|"publishes /cmd_vel"| CMD(("/cmd_vel"))
CMD -->|"subscribes"| MOTOR["Motor driver node"]
Because every node only cares about the topics, you can unplug the LiDAR node and swap in a depth-camera node that publishes the same /scan topic — and the navigation node never even notices the change.
You program ROS nodes in Python or C++. Python is the friendlier starting point, and the ROS 2 Python API (rclpy) is well documented.
Why robot builders care
Once your robot needs to do more than one thing at a time — navigate a room, avoid obstacles, stream video, respond to voice commands — coordinating all those tasks becomes genuinely hard. ROS handles that coordination for you.
You also get a whole ecosystem of off-the-shelf packages. Navigation stacks, SLAM implementations, sensor drivers, simulation tools — they’re all there, already tested, ready to drop into your project. Starting from scratch with all of that would take months. With ROS, you’re standing on the shoulders of a large open-source community.
Get started
The best way in is to pick a concrete robot and follow it through. Kevin built Cubie-1 specifically as a ROS learning platform — a 3D-printed Raspberry Pi 4 rover designed to grow with you as you work through ROS concepts. Read about the build at Meet Cubie-1.
From there, the Learn ROS with me course walks you through ROS 2 from first principles using Python, covering nodes, topics, services and more. It’s the most direct path from zero to a working ROS robot on this site.
Once you’re comfortable with the basics, SLAM (Simultaneous Localisation and Mapping) is the natural next step — your robot builds a map of its environment while navigating it. Kevin’s Viam SLAM article shows one approach to this using a Raspberry Pi and a LIDAR sensor, which gives you a taste of what’s possible.
Install ROS 2 on a spare Raspberry Pi, run through the official “turtlesim” tutorial to get the concepts straight, then come back and build something that actually moves.
Reacts well with
More Robot Intelligence
- AiArtificial Intelligence
- CvComputer Vision
- MlMachine Learning
- SlSLAM
- PdPID Control
- IkInverse Kinematics
- NvNavigation
- AuAutonomy
- SwSwarm Robotics
- NnNeural Networks
- LmLLMs
- EtRobot Ethics
Learn more on KevsRobots
Courses
Projects to build
Articles to read
Share this element
This page is awesome? Show some love!Did you find this content useful?
If you found this high quality content useful please consider supporting my work, so I can continue to create more content for you.
I give away all my content for free: Weekly video content on YouTube, 3d Printable designs, Programs and Code, Reviews and Project write-ups, but 98% of visitors don't give back, they simply read/watch, download and go. If everyone who reads or watches my content, who likes it, helps fund it just a little, my future would be more secure for years to come. A price of a cup of coffee is all I ask.
There are a couple of ways you can support my work financially:
If you can't afford to provide any financial support, you can also help me grow my influence by doing the following:
Thank you again for your support and helping me grow my hobby into a business I can sustain.
- Kevin McAleer
Comments