Getting Started with ROS2

Index

1. Introduction : Overview of the repository and Medium article series
2. How to Use This Repository : Steps to follow for theoretical and hands-on learning
3. Article List : Indexed list of articles with corresponding ROS2 example packages
4. Guides and Documentation : Installation, multi-machine communication, camera calibration, and ROS2 bag recording guides
5. Example Packages : Brief descriptions of included example packages
6. Raspberry Pi Image for ROS2 : Pre-configured image details and setup instructions
7. Contributing : Guidelines for contributions
8. License : Repository licensing information
9. Contact : How to reach out for queries or feedback

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Introduction

This repository complements the "Getting Started with ROS2" article series on Medium and it contains multiple guides and example packages for working with ROS 2. Follow the article series on Medium.

You can also check out the pre-configured Raspberry Pi image with Ubuntu Server 22.04 and ROS 2 Humble (Base + Perception).

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How to Use This Repository

1. Read the articles for theoretical understanding.
2. Clone this repository and navigate to the relevant example package.
3. Follow the guides for hands-on implementation.

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Article List

Sr.no.	Article	Example Package
1.	An Introduction	---
2.	Why ROS2?	---
3.	Install and Setup ROS2 Humble on Ubuntu 22.04(LTS)	---
4.	Overview of ROS2 Workspaces, Packages and Nodes	---
5.	Create and Set Up a Workspace	---
6.	Understanding Nodes	---
7.	How to Create Custom Packages and Nodes (with Python)	simple_node_example
8.	Understanding ROS2 Topics and Messages	pub_sub_tutorial
9.	What is a ROS2 Service? Implementing ROS2 Service-Client Nodes in Python	battery_status
10.	Asynchronous Task Handling using ROS2 Actions	---
11.	Implementing Custom Actions in ROS2	rotate_turtle_action_client
12.	A Step-by-Step Guide to Setting Up a Camera for ROS2 on Raspberry Pi and Desktop	---
13.	Mastering Data Recording and Playback with ROS2 Bag	---
14.	Visualising ros2 bag using RViz2	---
15.	How to Convert a ROS1 Bag to a ROS2 Bag	---

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Guides and Documentation

• installation_guide/: Step-by-step instructions for installing ROS 2 on a desktop, laptop, or Raspberry Pi, along with environment setup guidelines.
• ros2_multi-machine_communication_guide/: A comprehensive guide on configuring ROS 2 for multi-machine communication.
• raspi_headless_camera_calibration_guide/: Instructions for performing camera calibration on a Raspberry Pi without a graphical user interface.
• ros2_bag_recording_and_playback_guide/: Guidelines on recording and replaying ROS 2 bag files for data analysis and debugging.
• Rviz2_guide/: A guide to using Rviz2 for visualizing ROS 2 data from active nodes or recorded rosbag files.
• convert_ros1_bag_to_ros2_format_guide/: A guide on how to convert the ROS1 Bag to ROS2 format.

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List of example Packages:

• simple_node_example: A basic example demonstrating a simple ROS 2 node.
• pub_sub_tutorial: Illustrates the implementation of publisher and subscriber nodes for ROS 2 topics.
• battery_status: Demonstrates client-server node communication in ROS 2.
• rotate_turtle_action_client: Implements an action client node to control the movement of the Turtlesim TurtleBot.

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Raspberry Pi Image with Ubuntu Server 22.04 and ROS2 Humble Base + Perception

I have created a Raspberry Pi image with Ubuntu Server 22.04 for arm64 and ROS2 base + perception pre-installed to help you get started quickly. This image can be downloaded directly from this link, flash it to a SD card, and boot on a Raspberry Pi 3 or above model. In case, you are not able to use this image, you can install ROS2 on Raspberry Pi by checking the installation_guide directory or following this link.

How to Use the Image

Before you start, you need an SD card that is at least 16GB in size.

1. Download the Image File: Download the compressed image file from the link above.

2. Extract the Image File: The image is compressed with the .gz compression format. You will need to decompress it. Once decompressed, you should have a file that ends with the extension .img. On windows, try using 7-zip. On Mac/GNU-Linux, use gunzip ubuntu-server-22.04-ros2-base.img.gz

3. Write the Image to an SD Card: Use a tool like Etcher or Raspberry Pi Imager to write the extracted .img file to an SD card.

4. Insert the SD Card into Your Raspberry Pi: Unplug the SD card and plug it into your Raspberry Pi and power it on. Wait for atleast 5 minutes for the first boot.

5. Get your Raspberry Pi's IP Address: Make sure your System and Raspberry Pi is connected to the same Wi-Fi network. Try to ping the raspberry pi with the hostname.

   ping raspberrypi.local

   and get the ip address of Pi.

6. Access Your Raspberry Pi: The default username is ubuntu and the password is 6496. The default hostname is raspberrypi. You can login either directly on the Raspberry Pi or via SSH (enabled by default). Try:

   ssh ubuntu@raspberrypi.local

   or

   ssh ubuntu@<your-raspberrypi-ip-address>

7. Start Using ROS2: ROS2 is pre-installed and configured. You can start using it right away.

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Contributing

Contributions are welcome! If you have any suggestions or improvements, feel free to open an issue or submit a pull request.

License

This repository is licensed under the Apache 2.0 License. See the LICENSE file for more details.

Contact

For any questions or feedback, feel free to reach out or comment on the Medium articles. Happy coding!