SUBSCRIBER Node in ROS and debug with RQT_GRAPH | Tutorial #4 | ROS and Raspberry Pi

[@prandtlmayer]

Follow the whole series kzbin.info/www/bejne/hGeuY3-NfJeeiKs

[@indian2223]

why not catkin_make after creating subscriber?

[@mrpossible5696]

Thanks 😊

[@sainco3036]

thanks.

[@Benyaminmoadab]

how can qrcode detection with topic??

[@gorilla543210]

Nice video! Detail explained the code ! By the way, is the message variable also a pointer in python since it reference the string object? Thank you!

[@prandtlmayer]

Which line are you referring to? The callback?

[@gorilla543210]

@@prandtlmayer Yes, in line 11 to 12!

[@prandtlmayer]

Message is an argument passed by ROS when calls the callback function. It's of the same type you defined in the Publisher definition

[@雷电-o1p]

What if we use array data type? Having a problem for sending the array to the subscriber...

[@prandtlmayer]

What kind of problem?

[@mehulahal9203]

The subscriber node does not start up. As confirmed by 'rosnode list' that only shows '/rosout' (no 'simple_subscriber'). But no errors either? How could I fix this? Update: I tried running it directly in the python shell (launch by /usr/bin/env python) followed by `import rospy` and `rospy.init_node('simple_subscriber')`, and it worked. Also it doesn't work for `test_pub_sub/src/test_subscriber.py`, but works for `python test_pub_sub/src/test_subscriber.py` ? Regards

[@prandtlmayer]

You chmod?

[@ShanaAndJeff]

Just found your channel. Great quality videos! Just curious why “if __main__” and not “def __main__”?

[@prandtlmayer]

thanks for your support. __main__ is not a function. It's just the argument python calls your script with. You can import a script or directly run it. In this latter case, the argument __main__ is set equal to "__main__" from python. The part in that if statement is executed only when you run the script and not import it

[@ShanaAndJeff]

Tiziano Fiorenzani cool thanks for the explanation!

[@abdessamedbenaissa8760]

Thank you for the tutorial. Can we do the same thing with turtlebot3 burger ?

[@prandtlmayer]

Yes you can! This is just an example, you can make it much better and apply the lessons learned here to your project. Don't forget to post your videos in the comment