Running the Package¶
In a new terminal, run
The following should appear:
... logging to /home/pi/.ros/log/634b1d0a-4664-11ec-90e3-dca63268e7bc/roslaunch-raspberrypi-18104.log Checking log directory for disk usage. This may take a while. Press Ctrl-C to interrupt Done checking log file disk usage. Usage is <1GB. started roslaunch server http://raspberrypi:38727/ ros_comm version 1.15.11 SUMMARY ======== PARAMETERS * /rosdistro: noetic * /rosversion: 1.15.11 NODES auto-starting new master process[master]: started with pid  ROS_MASTER_URI=http://raspberrypi:11311/ setting /run_id to 634b1d0a-4664-11ec-90e3-dca63268e7bc process[rosout-1]: started with pid  started core service [/rosout]
roscore is the first command that should be run to allow for ROS nodes to communicate. The command essentially prepares your system by launching the pre-requisite nodes and programs needed for a ROS system.
rosclean check to check the disk usage of ROS log files. If disk usage >1GB, run
rosclean purge to clear existing ROS log files.
In another terminal, run
sudo suto run commands as root.
Running a command with the
sudo prefix is required for commands that require superuser privileges.
Switching to the superuser (root) can be dangerous, it grants access to “super powers” like the ability to modify or delete any file in any directory on the system, hence one should be careful with the commands run under the root account.
As the root user run:
echo "source /opt/ros/noetic/setup.bash" >> ~/.profile echo "source /opt/ros/noetic/setup.bash" >> ~/.bashrc echo "source /home/pi/catkin_ws/devel/setup.bash" >> ~/.profile echo "source /home/pi/catkin_ws/devel/setup.bash" >> ~/.bashrc
Close the root terminal and reopen it. Navigate to
cd catkin_ws/srcand run
sudo suonce again.
cd catkin_ws/src sudo su
Now, run the following command to start the nodes in the launch file.
roslaunch vmxpi_ros_bringup wrapper.launch
Configuring the Launch File¶
Navigate to the launch file directory in the file explorer and open the
cd /home/pi/catkin_ws/src/vmxpi_ros/vmxpi_ros_bringup/launch nano wrapper.launch
From the image above, there are three nodes in the xml launch file. The
camera_node and the
opencv_node are both commented out using the xml syntax
<!-- Comment -->. Remove these tags to have these nodes run when the launch file is called, or add them when not in use to save resources.
Observe the resource usage by running