ROS2 Programming Assignment 1 - Publisher / Subscriber

Overview

This repository is a simple ROS2 package that follows the Writing a simple publisher and subscriber (C++) tutorial from the ROS2 Docs. The package creates 2 nodes, 1 talker node that publishes a message to a topic and displays the message in the terminal, and 1 listener node that subscribes to the same topic and displays the recieved message from the talker node.

How to Build/Run

Create ROS2 Workspace

# Source ROS2 underlay
source /opt/ros/humble/setup.bash

# Navigate to the driectory location where you wish to create a ROS2 workspace
mkdir ros2_ws
cd ros2_ws/
mkdir src
cd src/
cd ..

colcon build

Clone and Build Repository

cd src/
git clone https://github.com/GraysonGilbert/my_beginner_tutorials.git
cd ..
colcon build --packages-select beginner_tutorials

Run Listener Executable

# From the same terminal that you just built the package in run the following:
. install/setup.bash
ros2 run  beginner_tutorials listener

Run Talker Executable

Open a new terminal and navigate to the ROS2 workspace directory previously created.

# Source ROS2 underlay
source /opt/ros/humble/setup.bash
# Source overlay
. install/setup.bash

ros2 run  beginner_tutorials talker

Launch both nodes at the same time with launch file

# Source ROS2 underlay
source /opt/ros/humble/setup.bash
# Source overlay
. install/setup.bash

ros2 launch beginner_tutorials launch_nodes.py publish_rate:=1.0

How to call service

ros2 service call /modify_message beginner_tutorials/srv/ModifyMessage "{modified_message: '<write message here>'}"

Now you should see a message being published to the terminal from the Talker node, and the Listener node recieving and publishing the same message in the other terminal.

Dependencies

This package assumes that you have ROS2 Humble properly installed and setup on your machine. If this is not the case, the steps to install ROS2 can be found here.