🤖 ROS2 Publisher–Subscriber Communication

🚀 A beginner ROS2 project demonstrating Publisher–Subscriber communication using Python (rclpy).

This project explains the fundamental ROS2 concept where one node publishes messages to a topic and another node subscribes to the same topic to receive those messages.

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📌 Project Overview

In ROS2, communication between nodes is commonly implemented using the Publisher–Subscriber model.

In this project:

• A Publisher Node sends a message "Hello ROS2" to a topic named chatter
• A Subscriber Node listens to the same topic
• The subscriber prints the received message in the terminal

This demonstrates the basic communication mechanism between ROS2 nodes.

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🛠 Technologies Used

Technology	Description
🤖 ROS2 Humble	Robotics middleware framework
🐍 Python	Programming language
📡 rclpy	ROS2 Python client library
📨 std_msgs	Standard ROS2 message types

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⚙️ Project Description

A ROS2 node publishes a string message "Hello ROS2" on a topic named:

chatter

Another node subscribes to the same topic and prints the received message in the terminal.

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📂 Project Structure

ros2-publisher-subscriber
│
├── publisher.py
├── subscriber.py
└── README.md

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📡 Publisher Node

The publisher node sends messages every 1 second.

Topic

chatter

Message Type

std_msgs/String

The node publishes the message "Hello ROS2" continuously.

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📥 Subscriber Node

The subscriber node listens to the chatter topic and prints the received message in the terminal.

Whenever a message is published, the subscriber immediately receives and displays it.

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▶️ How to Run the Project

1️⃣ Build the Workspace

colcon build

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2️⃣ Source the Workspace

source install/setup.bash

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3️⃣ Run Publisher Node

ros2 run my_pubsub_pkg publisher

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4️⃣ Run Subscriber Node

Open another terminal and run:

ros2 run my_pubsub_pkg subscriber

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💻 Output Example

[INFO] Hello ROS2
[INFO] Hello ROS2
[INFO] Hello ROS2

The subscriber node continuously receives and prints messages published by the publisher node.

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🎯 Learning Outcomes

This project helps understand:

• ROS2 node creation
• Publisher–Subscriber communication
• ROS2 topics
• Message passing between nodes
• Python-based ROS2 development using rclpy

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👨‍💻 Author

Omkar Honrao Robotics & Automation Enthusiast

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