Questions tagged [publisher]

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Intel RealSense D455 is not working with ROS noetic in Jetson Orin Nano

I tried connecting the Realsense D455 camera, to get point cloud information from the camera. Works fine on a PC. But when connected to Jetson Orin Nano, its shows up with the SDK and Realsense viewer ...
SpaceDoug's user avatar
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i wanna blink a led with pwm and a potentiometer attached to a ADS1115 modulle using ros2 pubsub package

i had a while ago with some help from this forum sending potentiometer values from a publisher node to a subscriber node to blink a led in pwm but the led doesnt seem to receive values the talker node ...
Jonathan Dawsa's user avatar
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Is there an architecture in ROS 2 to put “backpressue” on upstream nodes to slow is down?

Pipeline description: Node A - Camera Driver Node that publishes images(topic 1) at 30 Hz. Node B - Objection detection Node subscribes to images(topic 1) and publishes 2D detections(topic 2) Node C -...
ashwin kuruttukulam's user avatar
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Decreased Hz Rate and Lag in Image Transfer with Multiple Subscriptions in ROS2 Communication

I'm encountering a problem in my ROS2 (Robot Operating System 2) communication setup where I've noticed a significant decrease in the frequency of data updates (measured in Hz) and increased lag in ...
Teja's user avatar
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2 answers
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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 ...
FourierFlux's user avatar
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When will subscriber status callbacks be available in ROS2?

What are the plans for implementing rclcpp subscriber status callbacks (connect/disconnect) in ROS2? I found this ROS1 feature quite handy. Note that this question has been asked before but since that ...
Bernd Pfrommer's user avatar
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1 answer
32 views

Calling ROS2 subscriber callback function from another function

I try to use x and y in timer_callback function but I get ‘x’ was not declared in this scope I don't know how can I do this ...
HCA's user avatar
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1 answer
104 views

C++ Publisher and Subscriber in ROS2

I use Ubuntu 20.04 and Ros2 Galactic when I run the code I'm able to get subscribe information and pub this information and also I can see publisher information on topic echo continuously but when I ...
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2 answers
114 views

Oriented Bounding Box in RVIZ

I want to visualize an OrientedBoundingBox from Open3D on RVIZ, I have seen the : RvizVisualTools::publishWireframeRectangle RVIZ Line Segments ...
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ROS 2 Humble: RCLError: Failed to publish: Publisher;s contexxt is invalid

I am at the start of my journey learning to use ROS 2 Humble with the iRobot Create 3. I wrote a publisher to its light ring leds that allow me to override the control to the light ring and change the ...
Benjy's user avatar
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1 answer
70 views

How to set/change QoS deadline for a publisher node during/before runtime

There is an active topic "/control/drive_inputs" that I'm trying to publish to using ...
Victor's user avatar
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1 answer
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Turtlesim: Stop after one turn. Subscriber way faster than the Publisher

I am interested in drawing one circle with the turtlesim. However the subscriber is retrieving the pose way faster than the publishers moves the turtle. This is the code that I came up with: ...
p10's user avatar
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Does rclpy supports intraprocess communication?

I wanted to know if rclpy supports intraprocess communication or is there a way to do intraprocess in rclpy with python based libraries? Thanks,
Kirito's user avatar
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2 answers
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How to copy the Python variable to inside another class?

This encoder reader and publisher node needs to access another class (Rotary) to get the encoder ticks. The printer on line 11 works fine, but publishing on line 39 doesn't get the data; it only ...
Russ76's user avatar
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214 views

[ROS2][std_msgs::msg::Int8] publisher and create_publisher

Version: Ubuntu 22.04 , ROS2 Humble ERROR description I want to create a publisher that publishes std_msgs::msgs::Int8 messages, but when I write according to the ...
Lydia's user avatar
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Subscriber in python to std_msgs.msg.Float32 crashes when the maximum float-32bits is sent

Setup: a publisher in c++ of std_msgs/msg/Float32 sends the maximum float-32bits (using std::numeric_limits::max()) a subcriber in c++ to the topic above works just fine a subcriber in python to the ...
POtaoPereiraRosen's user avatar
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Multiple publishers and a timer to publish tf in the same node is leading to crash

Description I have a node that publishes 2 topics and a timer to publish TF using ros-noetic. However this setup throws an exception: ...
ignacio's user avatar
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Ros2, topics still persist after subscribers/publishers go out of scope

I have a map plugin I've made for rqt_gui that I am going to be using to visualize location information from n number of ROVs/autonomous vehicles. So far I am able to find and create subscribers to ...
supermepsipax's user avatar
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ROS 1 Stereo image pairs splitter node migration to ROS 2 Galactic

I have modified the ROS 1 source from this repo to use in ROS 2 galactic While I am able to satisfy the package dependencies, I'm having issues with the following code: ...
andrewb's user avatar
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1 answer
50 views

Rosserial missing subscribed messages

I'm making a humanoid robot kid size and ros noetic to control several dynamixel MX28-AT. I have a code to receive angles calculated in the high level using rosserial to connect with teensy4.0 at ...
Lucas Ólives's user avatar
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1 answer
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UM7 Orientation Sensor IMU not Publishing at 255 Hz. It is around 20-45 Hz, How to fix?

I really want to ask you about the UM7 Orientation Sensor we purchased. We want so much to use the UM7 in our research. As it is mentioned on the Pololu website, the IMU transmits data using human-...
Matthew Lisondra's user avatar
2 votes
0 answers
184 views

Destroying a publisher using node.destroy_publisher raises Invalid Handle exception

I'm trying to trigger a camera which is configured to use trigger mode in ROS2 Humble, Gazebo. I create a publisher inside a state in our state machine, to publish the trigger topic. Once the state ...
silkjc's user avatar
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1 answer
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Rospy getNumSubscribers()

In rospy do you have a getNumSubscribers() function for the Publisher? Originally posted by schizzz8 on ROS Answers with karma: 183 on 2023-06-03 Post score: 0
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rospy and Subscriber/Publisher garbage collection

Do I need to store a reference to rospy subscribers and publishers to avoid these objects to be garbage collected? ...
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1 answer
37 views

Should I unregister from Publishers/Subscribers when I terminate a ROS node by exiting the script?

Hi everyone. So my question is pretty much what the title is. Is it good practice or even necessary to unregister from ROS publishers or subscribers I used inside my ROS node before terminating the ...
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1 answer
100 views

Processing pointcloud2 using ros node with both publisher and subscriber

I am trying to process a pointcloud2 being generated by the /map topic, which I play from a rosbag file containing the topics /tf, /map, /ssl_slam/trajectory topics. By process, I mean I want to ...
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1 answer
58 views

Subscribing and publishing to the same topic (/map) in a single python ros node

My goal is to process a PointCloud2 and visualize it in RViz. I have rosbag data collected. This rosbag file includes /map, /tf, /ssl_slam/trajectory topics. The /map topic is in the form of ...
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1 answer
25 views

What does tilde(~) mean in ROS?

I have this sample of code: def ranger(channel, frame_id): range_pub = rospy.Publisher('~', Range, queue_size=10) rate = rospy.Rate(15) and this sample ...
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2 answers
14 views

How to publish map continously?

I am using map_server out-of-the-box to publish a pre generated map on the topic /map. But it only publishes the map once on the ...
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1 answer
14 views

What are the differences between broadcaster and publisher

Hi guys, I am new to ROS, and I just learned some ROS tutorials. I found that in some tutorials, they refer to a node as the "publisher", such as the "image publisher" in http://...
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1 answer
48 views

Dynamic publishers, subscribers and callbacks

I am trying to create a multi-robot system (MRS), where multiple robots are communicating with each other over ROS2, Galactic, Ubuntu 20.04. Currently, I'm only running this in simulation, but I have ...
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1 answer
165 views

Best way to integrate ndarray into ros2

Hello, I have a numpy ndarray, and when I try and publish it, I get this error: ...
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1 answer
16 views

Why is spinOnce() right after publish() flaky?

I have a simple C++ test code which contains a subscriber, a publisher and nothing else. I do the following: Set up subscriber sub with queue size 1. Set up ...
Martin Pecka's user avatar
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1 answer
32 views

ros publisher not publishing in debug

Hi I'm running my node in debug (vscode) and getting weird results. I have a loop which is publishing to a motor ...
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1 answer
4 views

I'd like to publish a subscriber code

I get this kind of error.I don't know. Please help me. ...
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1 answer
12 views

compile error related to <nav_msgs::Path> publisher

I am trying to publish the path produced by my global_planner plugin (named my_global_planner) using a publisher named ...
skpro19's user avatar
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2 answers
169 views

ROS2 sending multiple inputs msg

hi, im trying to send four floats like 20.0,20.0,320.0,20.0 in a msg on a publisher node, but it realy doesnt like to send the numbers. ...
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1 answer
243 views

How do you kill the "zombie" node in ROS2 on local?

I've programmed the publisher to create "/scan" however. that is the grave mistake. After close all ros2 applications, I noticed the /scan still running even if there is nothing runs it. It'...
Garrett Fogerlie's user avatar
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2 answers
19 views

publish after processing data from 2 synced subscribers (rospy)

I want to make one node to subscribe 2 topics synchronously, process those data, and publish it. I know that publishing and subscribing data with single node is possible, but have never seen any ...
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1 answer
1 view

Run publisher in a separate callback like function

Is there a way to have a callback function similar to that of subscribers to run a function that publishes to a topic at regular intervals? I guess it could be done anyway with threading but is there ...
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1 answer
6 views

Latency in publisher/subscriber

Hello everyone, In a somewhat big project i'm working on, I'm stubbling on an issue. I have 2 nodes, one focus on perception and the other one generating speed control order for a UR10 robot. The ...
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2 answers
72 views

how to subscribe to laser /scan topic and publish a customized scan topic back

hi, i want to consider any 72 points from the 'scan' topic for my other application. Currently the lidar i am using gives around 2000 points. I want to take only 72 points out of it and publish it as ...
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1 answer
3 views

fail to publish to a different message type

Hi everyone :) I wrote a node called translater that subscribes to a the topic pose_before and publishes to another topic pose_after. The topic pose_before is of message type "...
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1 answer
6 views

Get all topics that publish a given message?

How to get the names of all topics that publish a given message? E.g. when I add an image viewer in RVIZ, it already lists for you all topics that publish a ...
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0 votes
1 answer
31 views

What are the differences between the different TransportHints?

Hi all, Context: This week, I've experimented with publishing/subscribing and measured communication times with different TransportHints. More precisely, I've tried sending a fairly large custom ...
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1 answer
12 views

Publisher-Subscriber node not invoking callback function in python

Hello, so I'm trying to do a node where I publish a Twist message on cmd_vel to control a differential robot using the keyboard. I'm doing a PID control to correct some orientation problems on the ...
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1 answer
3 views

vehicle cmd topic subscription and message error display

Hi Guys, Anyone has any ideas on this please. ...
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1 answer
35 views

[ROS2] publishing UInt16

Hi, I would like to publish a message without it being of type std_msgs::msg::String. ...
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1 answer
16 views

Can anyone please help me, struggling to convert between quaternions and euler angles

Straight copy of the script: ...
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2 answers
2 views

When exactly is a connect callback of a publisher called?

Hi all, I would like to know when precisely the connect_cb is being invoked, specified in ...
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