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Subscriber Error

asked 2016-04-04 15:28:38 -0500

Emilien gravatar image

updated 2016-04-07 04:28:33 -0500

ahendrix gravatar image

hi, i create a rosserial_python node with arduino which publish ultrasound data. and also, i create a node in my PC which subscribe to ultrasound data. but when i run rosrun to subscribe, i receive special characters.
can you help me please? i think that is convertion uint8_t to string but i don't know how can i do it.

UPDATE

#include "ros/ros.h"
#include "std_msgs/Int8.h"

void angleCallback(const std_msgs::Int8& servo_msg)
{
    ROS_INFO("I turn: [%i]", servo_msg);
}

int main(int argc, char **argv)
{
    ros::init(argc, argv, "angle_listener");
    ros::NodeHandle n;
    ros::Subscriber sub = n.subscribe("/servo", 1000, angleCallback);
    ros::spin();
    return 0;
}
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Comments

Better if you could put the code and what you receive. Those "special" characters.

At first look could be that the field of the message where you want to put the ultrasound data doesnt have the same type as the data itself. For example in the msg file appears as string what in reality is an array.

thepirate16 gravatar image thepirate16  ( 2016-04-04 17:43:14 -0500 )edit
1

You keep asking questions and then deleting them; even the ones that are answered. This is bad etiquette, and by constantly changing the question title you decrease the chance that someone will see and answer your question.

ahendrix gravatar image ahendrix  ( 2016-04-04 18:03:16 -0500 )edit
2

You've done this enough times and offended enough other users that I'm setting your account to moderated.

ahendrix gravatar image ahendrix  ( 2016-04-04 18:04:11 -0500 )edit

ok thank you

Emilien gravatar image Emilien  ( 2016-04-05 02:20:28 -0500 )edit

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answered 2016-04-07 04:34:55 -0500

NEngelhard gravatar image

Have a look at the message definition: http://docs.ros.org/jade/api/std_msgs... You have to access the data-member.

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Comments

i don't understand you. can you explain it more please?

Emilien gravatar image Emilien  ( 2016-04-07 07:07:47 -0500 )edit
1

Since the Int8 message has a member called data, you use servo_msg.data to get the data.

ahendrix gravatar image ahendrix  ( 2016-04-09 13:47:27 -0500 )edit

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Asked: 2016-04-04 15:28:38 -0500

Seen: 140 times

Last updated: Apr 07 '16