Hello ROS Developers!

In today’s video we are going to see what is ROS Subscriber and how to see a list of them in a ROS Topic.

Before we start, if you are new to ROS and want to Learn ROS Fast, I highly recommend you to take any of the following courses on Robot Ignite Academy:

• ROS Basics In 5 Days (Python)
• ROS Basics In 5 Days (C++)

We love feedback, so, whether you like the video or not, please leave a comment on the comments section below so that we can interact and learn from each other.

Step1. Create a project in Robot Ignite Academy(RIA)

We have the best online ROS course available in RIA. It helps you learn ROS in the easiest way without setting up ROS environment locally. The only thing you need is a browser! Create an account here and start to browse the trial course for free now! We’ll use the ROS Basics in 5 Days course unit 0 as an example today.

Step2. What is ROS Subscriber?

Let’s start by visualizing the relationship between nodes with

rqt_graph

You can see that the nodes are communicating using the topics. A node can be a publisher publishing some topic or a subscriber to some topic. A topic can even have as many subscribers as you want.

For example, if you use the following command

rostopic echo /camera/rgb/image_raw __name:=subscriber1 > /dev/null

You can add a new subscriber called subscriber1 to the /camera/rgb/image_raw topic and you can add more subscribers if you want.

Edit by: Tony Huang