README.md

Zephyr AHRS sensor fusion library

This repo implements a Zephyr RTOS module which provides a Zephyr sensor fusion device driver which autonomously fetches accelerometer, gyroscope and (optionally) magnetometer data and does sensor fusion using a revised Madgwick AHRS algorithm implemented by XIO Technologies. More info about the algorith can be found here: https://github.com/xioTechnologies/Fusion/

Usage

1. Add module to your project manifest file

   Include this module in your project's west.yml manifest file, e.g.:

   manifest:
     self:
       path: <name_of_your_project>
   
     projects:
       - name: sensor-fusion-ahrs
         path: modules/lib/sensor-fusion-ahrs
         url: https://github.com/tmilkovic51/zephyr_sensor_fusion
         revision: v1.2.6
         submodules: true
   

   Take note of the submodules: true line. If this line is not present, the module won't be able to clone the XIO Technologies' AHRS sensor fusion library when running west update command.

2. Add device tree node to your board device tree

   In your board device tree, under a root node, create a device tree node with zephyr,sensor-fusion-ahrs compatible string, e.g.:

   / {
       sensor_fusion: fusion {
           status = "okay";
           compatible = "zephyr,sensor-fusion-ahrs";
           accel-dev = <&accel0>; /* Accelerometer device phandle */
           gyro-dev = <&gyro0>; /* Gyroscope device phandle */
           magn-dev = <&magn0>; /* Magnetometer device phandle */
       }
   }
   

   You need to have accelerometer, gyroscope and, optionally, magnetometer devices present and enabled in your board device tree.

   To configure other AHRS algorithm settings, please take a look at the bindings file.

3. Use the driver from your application code

   Include <sensor_fusion/sensor_fusion.h> header file in your application and call Zephyr sensor API fetch and get functions with custom-made sensor fusion channels:

   • SENSOR_FUSION_CHAN_YAW - Euler angle - yaw, in degrees
   • SENSOR_FUSION_CHAN_PITCH Euler angle - pitch, in degrees
   • SENSOR_FUSION_CHAN_ROLL Euler angle - roll, in degrees
   • SENSOR_FUSION_CHAN_YAW_PITCH_ROLL - all three Euler angles (yaw, pitch, roll), in degrees
   • SENSOR_FUSION_CHAN_LINEAR_ACCEL_XYZ - Linear acceleration measurement equal to the accelerometer measurement with 1 g of gravity removed, in g
   • SENSOR_FUSION_CHAN_EARTH_ACCEL_XYZ - Earth acceleration measurement equal to accelerometer measurement in the Earth coordinate frame with 1 g of gravity removed, in g
   • SENSOR_FUSION_CHAN_MAGNETIC_HEADING - magnetic heading in convention configured in device tree, in degrees

   There are also custom-made attributes that can be used with Zephyr attr_set and attr_get API:

   • SENSOR_FUSION_ATTR_MAGN_HARD_IRON_VECTOR - magnetometer hard ironing 3D vector, in X-Y-Z order, applied to each magnetometer measurement
   • SENSOR_FUSION_ATTR_MAGN_SOFT_IRON_MATRIX - magnetometer soft ironing 3x3 matrix, in row-major order, applied to each magnetometer measurement