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unable to use custom messages on arduino

asked 2013-03-07 11:13:12 -0500

hd271 gravatar image

updated 2013-03-07 20:31:20 -0500

fergs gravatar image

Hi Guys,

I'm trying to write a ros publisher on an arduino Uno using a custom message type and am running into compile errors for the arduino code. I followed the instructions here: link:http://ros.org/wiki/rosserial_arduino/Tutorials/Adding%20Custom%20Messages#Adding_Custom_Messages.28Generating_Message_Header_File.29 (Rosserial_arduino custom messages) and I'm able to include the generated header file. I then get the following error when I try to instantiate a variable of the message type:

I2C_Send_and_Receive.cpp:21:25: error: cannot declare variable ‘encoders’ to be of abstract type ‘GCRobotics::Encoder_msg’
In file included from I2C_Send_and_Receive.cpp:7:0:
/home/josh/sketchbook/libraries/ros_lib/GCRobotics/Encoder_msg.h:12:9: note:   because the following virtual functions are pure within ‘GCRobotics::Encoder_msg’:
In file included from /home/josh/sketchbook/libraries/ros_lib/std_msgs/Time.h:7:0,
                 from /home/josh/sketchbook/libraries/ros_lib/ros/node_handle.h:38,
                 from /home/josh/sketchbook/libraries/ros_lib/ros.h:38,
                 from I2C_Send_and_Receive.cpp:5:
/home/josh/sketchbook/libraries/ros_lib/ros/msg.h:44:19: note:  virtual int ros::Msg::serialize(unsigned char*) const
/home/josh/sketchbook/libraries/ros_lib/ros/msg.h:47:28: note:  virtual const char* ros::Msg::getMD5()

My code for creating it looks like this:

#include <ros.h>
#include <Wire.h>
#include <GCRobotics/Encoder_msg.h>
#include <GCRobotics/i2cData.h>
#include <std_msgs/String.h>

#include <TimerOne.h>

ros::NodeHandle n;
//std_msgs::String encoders;
GCRobotics::Encoder_msg encoders;
ros::Publisher pub("EncoderData", &encoders);

Im using Groovy and arduino 1.0.1, Any ideas on what I'm doing wrong or missing?

Thanks!

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answered 2013-03-07 20:28:25 -0500

fergs gravatar image

Under groovy (and even under Fuerte to a lesser extent) the older rosserial package is pretty busted (as it depended on internal roslib functions that have changed/disappeared). I would suggest trying out the new catkin-based version hosted here: https://github.com/ros-drivers/rosserial -- it will automatically build all messages for all installed packages found by rospack when running the make_libraries script. Please do read the README as the workflow has changed (but is probably simpler) from the past.

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Awesome, that worked for one of my machines, but the other machine i'm running gives me this error when running make_libraries.py: rospkg.common.ResourceNotFound: kobuki_qtestsuite. But as long as one of them generates them, I guess I can just copy to the other. Thanks for your help!

hd271 gravatar image hd271  ( 2013-03-08 10:33:44 -0500 )edit

I've patched rosserial temporarily to blacklist kobuki_testsuite. There is a ticket for it as well for a future, proper, patch (https://github.com/ros-drivers/rosserial/issues/30)

fergs gravatar image fergs  ( 2013-03-08 19:31:09 -0500 )edit

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Asked: 2013-03-07 11:13:12 -0500

Seen: 1,245 times

Last updated: Mar 07 '13