Magnetometer Visualizer Plugin (RQT)

Overview

The Magnetometer Visualizer Plugin is an RQT plugin for ROS1 that provides visualization and monitoring of magnetic field data published as sensor_msgs/MagneticField messages.

The plugin displays a live graph of X, Y, and Z magnetic field components and provides configurable thresholds and scaling.

Works perfectly with our magnetometer package

Requirements

Install required ROS packages:

sudo apt install ros-noetic-rqt ros-noetic-rqt-common-plugins

Make sure the following Python packages are installed:

pip3 install numpy matplotlib

Installation

Clone the repository into your Catkin workspace:

cd ~/catkin_ws/src
git clone git@github.com:CJT-Robotics/magnetometer_visualizer_plugin.git

Build the workspace:

cd ~/catkin_ws
catkin_make

Source your workspace:

source devel/setup.bash

Usage

Run your node that publishes sensor_msgs/MagneticField.

Launch RQT:

rqt --force-discover # After first run, --force-discover is unnecessary

Load the plugin: Plugins → CJT-Robotics → Magnetic Field Monitor

Configuration

Topic Selection

• Automatically lists all topics of type sensor_msgs/MagneticField
• Or type in manually a topic name

Settings

• Unit Scaling: Convert Tesla values to mT, µT, or nT
• Buffer: Number of stored data points (history length)
• Threshold: Detection threshold for highlighting anomalies
• Y-Axis: Controls zoom level of the graph

Visualization

• Red: X-axis

• Green: Y-axis

• Blue: Z-axis

• Yellow highlight: Values exceeding threshold

• Status box:

  • MONITORING: Normal operation
  • DETECTION: Threshold exceeded

Troubleshooting

Plugin not visible in RQT

• Make sure the workspace is sourced:

source ~/catkin_ws/devel/setup.bash

No topics available

• Ensure a node is publishing sensor_msgs/MagneticField
• Check with:

rostopic list

No data shown

• Verify message content:

rostopic echo /your_topic