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Python and C++ nodes [closed]

asked 2012-02-08 11:03:38 -0500

ing_jluispr gravatar image

updated 2014-01-28 17:11:18 -0500

ngrennan gravatar image

Hi!. I'm usung ubuntu 10.04 and ROS electric. I'm trying to move the turtlesim in the beginners_tutorials with voice using the pocketsphinx package. All nodes in pocketsphinx are made in Python, and as you should know turtlesim nodes are made in C++. I'm programming my node in Python but it can't import the Velocity message from the turtlesim package,(For that I'm using: from turtlesim.msg import Velocity.) My publisher is defined as: = rospy.Publisher("turtle/command_velocity", Velocity) What am I doing wrong?, Is it possible to publish/subscribe python and c++ nodes between each other?

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Closed for the following reason the question is answered, right answer was accepted by kwc
close date 2012-02-29 07:47:15


Please be more specific with exact error message that you're getting. What do you mean it "can't import the Velocity message"
David Lu gravatar image David Lu  ( 2012-02-08 11:40:07 -0500 )edit

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answered 2012-02-08 11:44:03 -0500

Thomas D gravatar image

It is possible to use Python and C++ nodes together. The ROS message system is language agnostic. I wrote a tutorial showing how to do that.

We do need more details about your error message importing the Velocity message to help with that part.

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I'm following your tutorial. I have all the files you need for running the examples, but when I'm trying to run the node surprisingly it shows me the same error that it showed when I was trying to run my own voice control node. It says: ImportError: No module named node_example.msg.
ing_jluispr gravatar image ing_jluispr  ( 2012-02-09 04:56:50 -0500 )edit

answered 2012-02-09 01:39:03 -0500

ing_jluispr gravatar image

Thank you very much!

I will follow the tutorial and try to lear how to mix the nodes. I'm using 3 nodes for my test. The recognition node whitch is provided by the pocketsphinx package (everything running well), my own voice control node and the turtlesim_node. When I make my package everything seems to be right. But when I run the launch whitch shows my 3 nodes, the voice control node starts and then stops inmediatly. The console shows that the module turtlesim.sms coundn't be found, that maybe it doesn't exit.

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answered 2012-02-08 11:40:49 -0500

David Lu gravatar image

Yes, it's possible if the turtlesim has properly generated its messages, which it will do when it is rosmade.

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answered 2012-02-09 07:36:14 -0500

ing_jluispr gravatar image

It's done!. It was just a dependeces problem. But actually the tutorial posted above was quite usefull. Thank you!

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Asked: 2012-02-08 11:03:38 -0500

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Last updated: Feb 09 '12