Introduction to ROS Part 3 - Nodes, Topics, Publishers, and Subscribers with Python

Learn to build your first ROS 2 nodes in Python by creating publisher and subscriber applications from scratch using rclpy, the official Python client library for ROS 2. Set up a ROS 2 workspace inside a pre-configured Docker container and create a new Python package using the ros2 pkg create command while understanding the purpose of each file and folder, including package.xml, setup.py, and the resource/ directory. Write a complete minimal publisher node that broadcasts "Hello world" messages to a topic, register it as an executable, build the package using colcon, and verify message transmission using ROS 2 command line tools. Develop a corresponding subscriber node that listens to the same topic and prints incoming messages to the console, demonstrating real-time communication between nodes. Explore ROS 2 node structure, topic functionality, and the importance of modular communication for scalable robotics applications while learning about node subclassing, Quality of Service (QoS) settings, and using rqt_graph to visualize connections between nodes and topics. Master the fundamental skills needed to create, build, and run basic ROS 2 Python nodes in a clean development environment, forming the foundation for all future ROS applications from simulation to real-world robotics implementations.