5. Calibration

5.1. Sensor Calibration

All of the sensors on MetaWear devices should be factory calibrated to produce an accurate reading out of the box. However, in some extreme cases, additional calibration may be required to get the best performance of our sensors in sensitive applications.

The following video from BOSCH describes a proven methodology for calibrating the orientation sensors on the MetaWear using either the BNO055 USB stick or the Bosch Sensortec application board together with the BNO055 shuttleboard.

5.2. Sensor Fusion

To calibrate our MetaSensors, please follow the steps below:

  1. Create an App in the language of your choice based on our available APIs.
  2. The App should connect to the MetaSensor.
  3. Then the App should stream values for the CalibrationState -> MblMwCalibrationState.
  4. While the App is streaming values, you should perform the BOSCH recommend calibration steps. You start by laying the device on a flat surface and you rotate it at 45-degree intervals until you get high accuracy on Calibration state.
  5. The App should read out the constants and save them into NVM using boot macros.

This steps are highlighted here: https://mbientlab.com/cppdocs/latest/sensor_fusion.html#calibration

A Python script is provided for your convenience for calibration purposes: https://github.com/mbientlab/MetaWear-SDK-Python/blob/master/examples/calibrate.py