ros_node_transformation

The package contains a node that can flexibly create a list of devices at runtime based on a configuration file. Each device can dynamically load a different publisher at runtime and change the type of data that pushes into the ROS network. It's an example application that showcases how a generic code along with a configuration file and the power of plugins can be used to create what would otherwise be multiple instances of repetitive and hardcoded pieces of code. There is an accompanying blog post that describes this concept.

Test

Install socat

sudo apt install socat

Create a directory for the serial ports

mkdir ~/dev

Create the serial ports

socat -d -d pty,raw,echo=0,link=/home/`whoami`/dev/ttyIMU pty,raw,echo=0,link=/home/`whoami`/dev/ttyIMU0 &
socat -d -d pty,raw,echo=0,link=/home/`whoami`/dev/ttySonarFront pty,raw,echo=0,link=/home/`whoami`/dev/ttySonarFront0 &
socat -d -d pty,raw,echo=0,link=/home/`whoami`/dev/ttySonarRear pty,raw,echo=0,link=/home/`whoami`/dev/ttySonarRear0 &

Write some data to the ports

function get_random {
  awk -v n=$1 -v scale=$2 -v seed="$RANDOM" 'BEGIN { srand(seed); for (i=0; i<n; ++i) { printf("%.4f", scale*rand()); if (i<n-1) printf(","); else printf("\n"); } }'
}

while true; do
  get_random 9 1 > ~/dev/ttyIMU0;
  get_random 1 10 > ~/dev/ttySonarFront0;
  get_random 1 10 > ~/dev/ttySonarRear0;
  sleep 0.02;  # 50 Hz
done

Install dependencies

sudo apt install ros-${ROS_DISTRO}-serial
# cd to <catkin_ws>/src
git clone https://github.com/nlamprian/ros_node_configuration.git

Download the package, compile and source the workspace, and finally start the launch file

roslaunch ros_node_transformation bringup.launch

The devices will publish data to a topic and diagnostic statuses.

To visualize the data in rviz, start with

roslaunch ros_node_transformation bringup.launch start_rviz:=true