Introduction to ROS Part 11: TF2 Broadcasters and Listeners | Digikey

In this video, we take a deeper dive into ROS 2 TF2, the transformation library that lets robots understand how different coordinate frames relate to each other. Whether you're controlling a mobile robot, coordinating multiple sensors, or building a manipulator with many moving joints, TF2 is essential for converting data between frames. We walk through a full example in turtlesim where one turtle dynamically follows another. We accomplish this by performing all calculations in the world frame, and then by using TF2 to express Turtle 1’s pose in Turtle 2’s frame of reference. The written guide for this episode can be found here: https://www.digikey.com/en/maker/tutorials/2025/intro-to-ros-part-11-tf2-broadcasters-and-listeners The GitHub repository containing the Docker image and example code for this series can be found here: https://github.com/ShawnHymel/introduction-to-ros You’ll learn how to write both a TF2 broadcaster and a TF2 listener in ROS 2 (Python), build a basic proportional controller, and create a frame tree that allows Turtle 2 to steer and rotate toward its target automatically. Instead of manually computing angles and offsets, we let TF2 handle the coordinate transformations so we can focus on higher-level robot behavior (just like you would in real robot navigation, SLAM, or multi-sensor fusion systems). Along the way, we visualize the frame graph, spawn additional turtles, and walk through the complete Python node used to control Turtle 2. We show how TF2 frames and transforms can be used to tackle more advanced robotics problems. This demo serves as a foundation for scaling up to real robots with moving parts, independent sensors, and complex kinematic chains. At the end, you’ll be challenged to scale the demo to multiple turtle bots, creating a full chain of follower robots!