mmc5603_compass

ROS2 Jazzy driver for MMC5603NJ 3-axis high-resolution magnetometer over I2C (MEMSIC).

The MMC5603 features 20-bit output resolution with ±30 Gauss fixed range, automatic set/reset for magnetic offset elimination, and continuous measurement mode up to 255 Hz ODR. It offers significantly higher resolution (1024 LSB/Gauss) compared to typical 16-bit magnetometers.

Features

• Publishes sensor_msgs/MagneticField on mag/data
• fake_mode for testing without hardware (random Gaussian data)
• 20-bit resolution (1024 LSB/Gauss)
• Automatic set/reset for offset elimination
• Configurable ODR (1–255 Hz), bandwidth (1.2–6.6 ms)
• Product ID verification (0x10)
• Hard-iron bias calibration via service call
• Runtime publish_rate change via ros2 param set

Prerequisites

• ROS 2 Jazzy
• Python 3
• smbus2 (pip install smbus2) — only needed for real hardware

Installation

cd ~/ros2_ws
colcon build --packages-select mmc5603_compass --symlink-install
source install/setup.bash

Usage

Launch (default: fake_mode)

ros2 launch mmc5603_compass mmc5603_launch.py

Direct execution

ros2 run mmc5603_compass mmc5603_node.py --ros-args -p fake_mode:=true

Real hardware (Raspberry Pi)

ros2 launch mmc5603_compass mmc5603_launch.py params_file:=my_params.yaml

YAML override

mmc5603_compass_node:
  ros__parameters:
    fake_mode: false
    i2c_bus: 1
    device_address: 0x30
    odr: 200
    bandwidth: "1.2ms"

Topic echo

ros2 topic echo /mag/data

Parameters

Parameter	Type	Default	Description
fake_mode	bool	true	Use fake driver (no hardware)
i2c_bus	int	1	I2C bus number
device_address	int	0x30	I2C address (fixed)
publish_rate	double	10.0	Publishing rate (Hz)
frame_id	string	mag_link	TF frame ID
odr	int	100	Sensor output data rate (1–255 Hz)
bandwidth	string	6.6ms	Measurement time: 6.6ms, 3.5ms, 2.0ms, 1.2ms
auto_set_reset	bool	true	Automatic magnetic offset elimination
magnetic_field_covariance	double	0.0	Diagonal covariance (T²)

Services

Service	Type	Description
mag/calibrate	std_srvs/srv/Trigger	Collect samples for 2s, compute hard-iron bias
mag/reset	std_srvs/srv/Trigger	Clear bias, reinitialise sensor

Package Structure

mmc5603_compass/
├── CMakeLists.txt
├── CONTRIBUTING.md
├── LICENSE
├── README.md
├── .gitignore
├── package.xml
├── config/
│   └── mmc5603_params.yaml
├── launch/
│   └── mmc5603_launch.py
├── nodes/
│   └── mmc5603_node.py
├── mmc5603_compass/
│   ├── __init__.py
│   └── mmc5603_driver.py
└── test/
    └── test_mmc5603_node.py

Test Results

Tested on Ubuntu 24.04 (WSL2) with fake_mode: true.

Test Category	Test	Result
Topics	mag/data publishes sensor_msgs/MagneticField	PASS
Services	mag/calibrate returns success=True	PASS
Services	mag/reset returns success=True	PASS
Parameters	publish_rate runtime change	PASS
Shutdown	Clean exit	PASS
Linting	pep257, flake8, copyright, xmllint	PASS

License

MIT