LSM303C magnetometer automatic calibration not working in Android

[IGEHI]

I use a LSM303C magnetometer sensor on an Android platform.

Sensor works fine, however automatic calibration (hard and soft iron) does not work. I checked it using an Android app displaying magnetic field vector in 2D, for both calibrated and uncalibrated data.

With my platform (Android 5.0 and ST MEMS driver + Android framework), calibrated and uncalibrated data are the same (red and blue text boxes), so it seems that there is no calibration algorithm running :

The same app tested on a Samsung S7 show calibrated and uncalibrated data after a full 360° rotation on Z axis, uncalibrated circle (red) is correctly shifted to calibrated circle (blue) :

How do I activate calibration on Android for LSM303C device ? ST framework code source mention an obscure STMagCalibration_API (which should do the job I guess), however i'm unable to find any source code for this library ...

Any Advice ?

[Eleon BORLINI]

hi, which kind of auto-calibration algorithm are you using? Pls consider that the suggested movement for the magnetometer calibration is not a full rotation around z-axis, but an 8-movement of the wrist carrying the magnetometer (in a smartphone) like the one shown in the picture below. Regards

[IGEHI]

Hi Eleon,

In fact, that's the point : I don't know how to enable magnetic auto-calibration on Android for LSM303C sensor. We uses the ST provided Android HAL (https://github.com/STMicroelectronics/STMems_Android_Sensor_HAL_Input) and it'seems that HAL can be configured for enabling auto-calibration. However when doing so, compilation miserably fails because of missing libraries. From the link above, I guess that some STM proprietary libraries are also needed :

"STM proprietary libraries

STM proprietary libraries are used to define composite sensors based on hardware (accelerometer, gyroscope, magnetometer) or to provide sensor calibration

SENSOR_FUSION:

The STM Sensor Fusion library is a complete 9-axis/6-axis solution which combines the measurements from a 3-axis gyroscope, a 3-axis magnetometer and a 3-axis accelerometer to provide a robust absolute orientation vector and game orientation vector

GEOMAG_FUSION:

The STM GeoMag Fusion library is a complete 6-axis solution which combines the measurements from a 3-axis magnetometer and a 3-axis accelerometer to provide a robust geomagnetic orientation vector

GBIAS:

The STM Gbias Calibration library provides an efficient gyroscope bias runtime compensation

MAGCALIB:

The STM Magnetometer Calibration library provides an accurate magnetometer Hard Iron (HI) and Soft Iron (SI) runtime compensation

The Android.mk file enumerates STM libraries supported by the HAL. The ENABLED_MODULES variable is used to enable support for proprietary STM libraries

ENABLED_MODULES := SENSOR_FUSION MAGCALIB GBIAS

"

But where to find them ? Do I miss something ? Is this the way to go ?

Regards.