[Turtlebot4 Lite] Issue of the TB-Lite sensors | Inconsistent data stream

I Hope you are doing well.
I have an issue concerning the topics /scan, /stereo/depth and /color/preview/image. Indeed, the behavior of the robot is random, sometimes it returns data and sometimes not. It arrives that I don’t change any condition of working, but the response can be different. I would like to know why I have this behavior?
Besides, I made another copy of turtlebot4-lite on a flash disk. It arrives me the same behavior as yesterday it works and today not. Furthermore, I would like to inform you that I didn’t install anything on the Ubuntu session of the robot of the new flash disk. It still new as I obtained using the rpi-images.
What are the packages that I have to install on the robot ?
To sum up, I would like to know the reason of this random behavior of /scan and /stereo/depth and /color/preview/image, and what are the packages that I should install on my new version of TB4-Lite.
Thank you.
Best regards,
Pr. Younès Raoui

Dear Prof. Raoui,

Pardon the delayed reply. The issue is not from turtlebot but actually from ROS2 and how dds works. It is not an issue but more of a feature that only allows stable communication.

Usually switching to a different type of dds enables smooth communication. However a flooded network and/or router may cause disruption in connectivity due to which topic data may not show up. More info on dds is here.

I would advise to take a look at the dda as a new image of tb4 lite should directly work correctly without any additional installation. Incase the issue persists, it may be worth looking into using getting a new image of tb4 lite as they regularly update it and it may have been a bug.

Also the tb4 github issues section covers these types of issues and provides workarounds for them.

Hope this helps!

Kind Regards,
S. O. Sohail