sakshikakde / beginner_tutorials

Python example to run publisher and subscriber in ROS Melodic.

beginner_tutorials

Introduction

This repository provides a simple example to run ROS publisher and sibscriber

File Structure

• include
  -- listener.hpp
  -- talker.hpp

• src
  -- listener.cpp
  -- talker.cpp
  -- listener_node.cpp
  -- talker_node.cpp

listener_node.cpp and talker_node.cpp are the files where the objectes for the classes Listener and Talker are created.

Building the package

1. Create a catkin workspace catkin_ws
2. Clone the package inside catkin_ws/src using

git clone https://github.com/sakshikakde/beginner_tutorials.git 

4. Change the directory

cd catkin_ws

5. run

catkin build 

How to run the code

1. Change the directory

cd catkin_ws

2. Source the workspace

sourcedevel/setup.bash

3. In a terminal, run

roscore

5. In a new terminal, run the talker by using

rosrun beginner_tutorials talker

5. In a new terminal, run the listener by using

rosrun beginner_tutorials listener

How to run the code(with launch)

cd catkin_ws

2)Source the workspace

sourcedevel/setup.bash

3. In a terminal, run

roslaunch beginner_tutorials talker_chatter.launch platform_name:="my_laptop"

Parameters

• platform_name : default="sakshi"
• publisher_topic_name : default="/chatter"
• publisher_rate : default = 20
• service_name : default="add_two_ints"
• subscriber_topic_name : default="/chatter"

ROS Service from command line

Use the following command to call the ros service from terminal:

rosservice call /add_two_ints "a: 10
b: 30" 

Run rostest

1. Change the directory to the workspace

cd catkin_ws

3. Build the workspace using the following command:

catkin build --catkin-make-args test      

3)Source the workspace

source devel/setup.bash

4. In a terminal, run

rostest beginner_tutorials test_broadcaster.launch

Recording the bag file

1. Change the directory to the workspace

cd catkin_ws

2. Source the workspace

source devel/setup.bash

3. In a terminal, run

roslaunch beginner_tutorials talker_chatter.launch record_bag:=true bags_directory:=/home/sakshi/courses/ENPM808X/week11/catkin_ws/src/beginner_tutorials/results/bag

Note that you need to update the bags_directory param to a suitable location

Running the bag file

1. Change the directory to the location where rosbag is recorded

2. Run the command

rosbag play <bagfile_name> --pause

3. In a new terminal, change the directory to the workspace

cd catkin_ws

4. Source the workspace

source devel/setup.bash

5. Run

rosrun beginner_tutorials listener

6. Unpause the bag file. the listener node should be able to get the topic messages from the bag file.