ROS on Raspberry Pi & Linux

What is ROS?

ROS (Robot Operating System) is not an operating system in the traditional sense — it is a flexible framework for writing robot software. It provides tools, libraries and conventions for building complex robot behavior across a wide variety of robotic platforms.

Why ROS?

Modular architecture — Nodes communicate via topics and services
Hardware abstraction — Same code runs on different robot platforms
Simulation support — Gazebo integration for testing without hardware
Large ecosystem — Thousands of packages available

Installing ROS on Raspberry Pi 4B

ROS2 Humble is recommended for Raspberry Pi 4B running Ubuntu Server 22.04.

Step 1 — Set up locale

sudo apt update && sudo apt install locales
sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8

Step 2 — Add ROS2 repository

sudo apt install software-properties-common curl
sudo curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key \
  -o /usr/share/keyrings/ros-archive-keyring.gpg

echo "deb [arch=$(dpkg --print-architecture) \
  signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] \
  http://packages.ros.org/ros2/ubuntu \
  $(. /etc/os-release && echo $UBUNTU_CODENAME) main" | \
  sudo tee /etc/apt/sources.list.d/ros2.list

Step 3 — Install ROS2

sudo apt update
sudo apt install ros-humble-desktop

Step 4 — Source the setup file

source /opt/ros/humble/setup.bash
# Add to .bashrc so it loads every terminal
echo "source /opt/ros/humble/setup.bash" >> ~/.bashrc

Core ROS2 Concepts

Nodes

A node is a process that performs a specific task. Nodes communicate with each other using topics, services and actions.

Topics — Publisher Example

import rclpy
from rclpy.node import Node
from std_msgs.msg import String

class Talker(Node):
    def __init__(self):
        super().__init__('talker')
        self.pub = self.create_publisher(String, 'chatter', 10)
        self.timer = self.create_timer(0.5, self.callback)

    def callback(self):
        msg = String()
        msg.data = 'SYSTEM ONLINE'
        self.pub.publish(msg)

def main():
    rclpy.init()
    rclpy.spin(Talker())
    rclpy.shutdown()

Topics — Subscriber Example

class Listener(Node):
    def __init__(self):
        super().__init__('listener')
        self.sub = self.create_subscription(
            String, 'chatter', self.callback, 10)

    def callback(self, msg):
        self.get_logger().info(f'Received: {msg.data}')

Installing on Linux PC

On a full Ubuntu 22.04 desktop you can install ROS2 Humble with the same steps. The desktop install includes Gazebo simulation and RViz visualization tools.

Test your installation

# Terminal 1 — run a demo talker
ros2 run demo_nodes_cpp talker

# Terminal 2 — run a demo listener
ros2 run demo_nodes_py listener

KEY INSIGHT: Always use ROS2 over ROS1 for new projects. ROS2 has proper real-time support, DDS middleware, Python 3 compatibility and active long-term support.

Conclusion

ROS bridges the gap between software and hardware in robotics. Once you master nodes, topics and services, you can build anything from a simple sensor reader to a fully autonomous robot platform.

Setting Up ROS on Raspberry Pi 4B and Linux