Introduction

This section describes installing RosBridge, which is useful for communicating to devices which do not have ROS installed (like windows machines with custom drivers)

Installing, Running, and Using RosBridge

from here and here

1. Install necessary prerequisites on the ROS machine ```bash #Install rosbridge on guest machine sudo apt install -y ros-melodic-rosbridge-suite

   ensure you have the most recent version of pip

   pip3 install --upgrade pip

   Install roslibpy client for rosbridge on guest machine

   pip3 install setuptools_rust service_identity roslibpy

   launch rosbridge server

   roslaunch rosbridge_server rosbridge_websocket.launch

   open up your favorite python editor

   spyder3 ```

2. start roscore on the guest:

   bash roscore

3. Run an existing talker in ROS. in a new terminal window: ```bash cd ~/catkin_ws source ./devel/setup.bash

   In the last tutorial we made a publisher called "talker". Let's run it:

   rosrun beginner_tutorials talker (C++)

   rosrun beginner_tutorials talker.py # (Python) ```

Non-ROS machine setup

1. install roslibpy (required if you did not do this in the prior step)

   bash pip install service_identity roslibpy

2. create a file called listener.py, substituting the ip address of the ROS Master for . Paste in the following:

   ```python

   -- coding: utf-8 --

   """ Created on Fri Mar 27 08:33:41 2020

   @author: danaukes """

   from future import print_function import roslibpy

   client = roslibpy.Ros(host='', port=9090) client.run()

   listener = roslibpy.Topic(client, '/chatter', 'std_msgs/String') listener.subscribe(lambda message: print('Heard talking: ' + message['data']))

   try: while True: pass except KeyboardInterrupt: client.terminate() except Exception as e: print(e) client.terminate() ```

3. Run from the editor(f5) or, in a new terminal window, navigate to the location of 'listener.py' and type:

   bash python3 listener.py

4. Now, create a file called talker.py, substituting the ip address of the machine for if on the host machine, or 'localhost' if in the guest machine. Paste in the following:

   ```python

   -- coding: utf-8 --

   """ Created on Fri Mar 27 08:36:13 2020

   @author: danaukes """

   import time

   import roslibpy

   client = roslibpy.Ros(host='', port=9090) client.run()

   talker = roslibpy.Topic(client, '/dancustom', 'std_msgs/String')

   while client.is_connected: talker.publish(roslibpy.Message({'data': 'Hello World!'})) print('Sending message...') time.sleep(1)

   talker.unadvertise()

   client.terminate() ```

5. on the guest machine, start a new terminal window, and type

   bash rostopic echo /dancustom