AK8975

AKM AK8975 SPI 3-axis magnetometer sensor module for XRobot.

This module initializes the magnetometer over a device-level SPI handle, samples magnetic field data in a background thread, applies the configured sensor-frame to application-frame rotation, publishes calibrated magnetic field vectors, and provides a RamFS shell command for status output and runtime calibration.

The ak8975_spi handle is expected to be prepared by the User layer. If the sensor shares a physical SPI bus with other devices, chip-select handling and bus locking should be encapsulated in that handle.

Required Hardware

• ak8975_spi
• ramfs

Constructor Arguments

• rotation: sensor-frame to application-frame quaternion
• data_topic_name: default "ak8975_mag"
• sample_period_ms: default 20
• task_stack_depth: default 1024

Published Topics

• data_topic_name: Eigen::Matrix<float, 3, 1>, magnetic field vector

Shell Commands

The module registers ak8975 in RamFS.

• ak8975 or ak8975 status: print chip ID, latest magnetic field data, and calibration state
• ak8975 cali: collect magnetic field extrema and update runtime offset / scale calibration

XRobot Configuration Example

- id: mag
  name: AK8975
  constructor_args:
    rotation:
      w: 1.0
      x: 0.0
      y: 0.0
      z: 0.0
    data_topic_name: "ak8975_mag"
    sample_period_ms: 20
    task_stack_depth: 1024