Questions tagged [msg-subscriber]

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How do ROS2 nodes find each other on the same computer?

I always assumed ROS2 nodes used sockets to communicate but it looks like they might also use shared memory or pipes. Regardless I'm curious how ROS2 nodes find each other? Lets suppose each node ...
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Issue to run a python executable code on ROS2

I have successfully tested my python deep learning code (Not a ROS node) for Pointcloud object detection using anaconda. In the prediction code, I can run ...
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ROS2 cannot import name 'iou3d_nms_cuda'

I am new to use ROS in my project. I have installed ROS2 humble on Ubuntu 22.04. I have successfully tested my python deep learning code (Not a ROS node) for Pointcloud object detection using anaconda....
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Issue to import libraries/moduls for a ROS2 python subscriber

I am new to use ROS in my project. I have installed ROS2 humble on Ubuntu 22.04. I need to import different python codes/functions as modules to a ROS2 subscriber (python code). They are: ...
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Raspberry Pi failing to subscribe to topic being published to by dev computer?

When running demo_nodes_cpp talker on the Dev computer and demo_nodes_cpp listener on my Raspberry Pi, the listener does not pick up the the message as it does when both nodes are running on the same ...
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Peek at the message queue for a ROS2 topic subscriber in a callback

I'm sure this facility was in ROS1 (although this post suggests it wasn't) but I cannot find it in ROS2. Basically in my subscription callback I want something like this pseudocode: ...
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Rospy subscriber calling only one thread

I am using python for programming the scripts in my ROS package, for a project. As part of the project, I need to implement a service client, which also subscribes to a topic. Specifically, the node ...
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Is the 'x' in ConstPtr& x in callback functions specific to message types?

Hi I'm new to ROS and I'm an amateur when it comes to pointers. I just did the subscriber and publisher tutorials and I am currently experimenting and converting them into classes for future use. I ...
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Dropping connection due to Datatype mismatch

Hi All, Kindly help me in finding a fix for this. I am playing a rosbag which has 5 topics. I want to create a new node and subscribe to one of topic from the rosbag. I am getting the below error when ...
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How can I subscribe to 2 different topics in a synchronised manner in ROS2?

I have 3 different nodes : Node2 subscribes to two different topics of same types published by node 1 and node3. Then it does some calculations on these subscribed topics and the publishes to a new ...
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No Matching Member Function for Call to Subscribe

I am calling subscribe, passing in a class member function and this current instance. Everything I am doing seems correct to me, but I'm getting No matching member ...
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AttributeError: 'list' object has no attribute '...'

Hello, I created a subscriber node to get data from a topic. Topic broadcasts humans on the camera in a list called human_list. I want to read this data with below code. However when I rosrun it I get ...
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Spin problem in ur_10 class

Hi, I have a class position.cpp where I manipulate my robot ur_10 and in this class I must to launch spinner.start() In this ...
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On demand Publishing?

I'm using ROS kinetic with Yumi package from KTH. I am getting some points from the camera and do some processing and send the coordinates back to the robot arms to move. What I'm doing is letting the ...
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1 answer
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Make gazebo subscribe to a ROS topic?

Hi, I've noticed that there are some ros topics that have the gazebo as a subscriber. Can someone tell me how can I make gazebo subscribe to a topic I create or where I can learn about it? Originally ...
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Problem with data from subscriber not going anywhere

Related question: https://answers.ros.org/question/278181/issues-with-seg-faults-and-node-not-publishing-anything/ In my code there are two subscriber functions. I want to pass the shared pointer data ...
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How to make a server read the latest msg from a topic?

Greetings, All I want to do is for my server to take a the latest msg from a topic and return it. The service server would take no inputs and return one output. Eg: Return robot position. Or Return a ...
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Data loss between publisher and subscriber

Hello I was running ROS package with one publisher and subscriber in below link. https://github.com/oroca/oroca_ros_tutorials/tree/master/src Basically, publisher sends a number (add 1 every loop) and ...
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