Introduction to ROS Part 12 - Talking to Microcontrollers

Learn to bridge the gap between ROS 2 simulation and real-world robotics by integrating middleware with actual robot hardware in this comprehensive 30-minute tutorial. Discover why ROS 2 functions as middleware rather than including direct hardware control libraries, and understand the critical role of microcontrollers in handling time-sensitive tasks like PWM motor control and interrupt handling. Explore the architecture using a Raspberry Pi 4B running Ubuntu 24.04 and ROS 2 Jazzy as the high-level computer, paired with a Raspberry Pi RP2350-based controller on the XRP educational robotics platform for low-level motor control. Master setting up serial communication over USB, writing Arduino firmware to parse motor commands, and building Python ROS 2 nodes that send real-time commands to hardware. Understand practical considerations including Linux's non-deterministic scheduling limitations and why the SBC + MCU architecture scales effectively to complex robotic systems. Follow along with installing ROS 2 on Raspberry Pi, configuring SSH and VS Code for remote development, setting up Python virtual environments, and creating custom ROS 2 packages with colcon. Implement a driver node with a state machine that controls robot movement through serial commands, demonstrating clean separation between high-level ROS 2 logic and low-level hardware control. Advance to computer vision integration using OpenCV to create a vision node that tracks colored objects and publishes bounding box data, while a driver node subscribes to this data to steer the robot toward targets in real-time, showcasing ROS 2's power in combining perception, decision-making, and hardware control into scalable robotic systems.