TurtleSim with ROS2

It’s been a few months since I installed ROS2, and honestly… I’ve just been letting it sit there.

Sure, I could say, “Well, I’ve been busy with hardware development,” but software is just as important.

So, I finally decided it’s time to dive in.

When you open ROS2 books, you’ll find all sorts of sample programs.

Among them, TurtleSim looked simple and fun—so I gave it a try.

“Wait, the turtle just moves?”

If that’s your reaction, you’re probably experienced.

But here’s the thing: if it moves with the keyboard, that means there are publishers (senders) and subscribers (receivers) working in the background.

For a beginner like me, this is the perfect starting point.

With a little help from ChatGPT, I ran these commands:

# Main node

ros2 run turtlesim turtlesim_node

# Keyboard control (keep active in the foreground)

ros2 run turtlesim turtle_teleop_key

# Turtle position info

ros2 topic echo /turtle1/pose

Here’s what it looks like when everything’s running:

Ah, I see! The position data is constantly being exchanged in the background.

If I can handle this data in Python, I should be able to make the turtle do all sorts of moves.

Trying to Draw a Spiral → Chaos Ensues

So I thought: “If I add a publisher that draws small circles while moving with the keyboard, won’t that create a spiral?”

But then, ROS complained that the publishers were conflicting.

When I asked ChatGPT, it suggested: “Why not merge them?” and even wrote some Python code.

Then came the unexpected question:

“Do you usually create a custom workspace for modified versions?”

Well, when asked like that, I had to answer “Yes.”

And that’s where the trouble began.

Turns out, I hit a bug in ROS 2 Jazzy + Python 3.12 where the new directory ended up completely empty.

I tried following ChatGPT’s advice and manually fixing it, but…

My energy ran out, and so did GPT-5’s session limit. That’s where I stopped for now.

This time, I played around with TurtleSim in ROS2, with a lot of help from ChatGPT.

I tested on Ubuntu, but I’m pretty sure it would also run on Windows using a virtual environment (if I remember correctly).

The key takeaway: TurtleSim might look simple, but it’s deeper than it seems once you start working with position data.

I’ll save the spiral-drawing challenge for next time.

Even just “making the turtle move” is a great entry point for learning how ROS2 works.

Next time, I’ll make sure my turtle draws a perfect spiral! 🐢✨