Unit 3 - Rosject Topics not showing

[rblazquezdiaz]

Hi, this is my first use of rosject so I am a bit confused.

I am attempting the Unit 3 Topics quiz from the ROS2 in 5 Days Python course.

The first command I used in the terminal of the ROS Development Studio (ROSDS) is “source /opt/ros/foxy/setup.bash” , as that was used in the unit examples. When I look at the list of topics only /parameter_events and /rosout come up.

I need the topics /cmd_vel and /odom for the quiz but I cannot get them. Am I missing any steps?

Thank you.

[girishkumar.kannan]

Hi @rblazquezdiaz ,

Welcome to the Community!

You need to launch the ros1_bridge parameter_bridge

# To launch ros1_bridge
source ~/catkin_ws/devel/setup.bash
roslaunch load_params load_params.launch
source /opt/ros/foxy/setup.bash
ros2 run ros1_bridge parameter_bridge

VERY IMPORTANT:
You need to have ros1_bridge running in one terminal. If you end it (by pressing Ctrl-C), the topics will disappear from ros2 topic list.
So run the above commands in one terminal and in another terminal do ros2 topic list to see bridged topics.

It is already specified in the rosject Notebook!

Regards,
Girish

[rblazquezdiaz]

Thank you for the reply. I am now attempting to launch the simulation but I cannot seem to get it.

source /opt/ros/noetic/setup.bash

source ~/simulation_ws/devel/setup.bash

roslaunch realrobotlab main.launch

That piece of code is the only thing I could find in the instructions, but that is not the simulation I need for the topics quiz in Unit 3.

Any idea?

Thank you!

[girishkumar.kannan]

@rblazquezdiaz ,

You must do the topics_quiz in the course environment and NOT in rosject / rosds.
Alll the exercises along with topics_quiz, services_quiz and actions_quiz MUST be done in the course environment.
Only the course project should be done in the rosds / rosject environment.

I hope that clarifies your confusion.

Delete your topics_quiz files from rosject environment and start a package from scratch in the course environment.

Course environment is the place where you have the course chapters displayed on left side, webshells on the bottom, the IDE on center and gazebo on top right.

Regards,
Girish