BMM150 auto calibration

[Ashwath]

Hi

  We are using BMM150 in our stepper motor application. We want to find the find the true  North from BMM150 and rotate the stepper motor. We found that BMM150 Values get affected due to stepper motor permanent magnets. Also we kept the i-phone / android phone and checked the compass results. 

1. We did not found any effect of permanent in case of i-phone / android phone compass. Phones are periodically doing auto calibration. How to do that with BMM150.  
2. Is BMM150 giving the true north or magnetic north?. How to get the true north using GPS data.

Please give us some light to move forward 

Thanks and best regards 

Ashwath

[FAE_CA1]

Hi,

In order to solve this issue, you need 9DoF sensor fusion with accel, gyro and mag. When you device is not moving and the electricity load increases, gyro will help maintain the heading. You can consider using BHI260AP + BMM150 two-chip solution for your design.

BHI260AP shuttle board 3.0 is avaiallbe at https://www.mouser.com/ProductDetail/Bosch-Sensortec/BHI260AP-Shuttle-Board-3.0?qs=sGAEpiMZZMuqBwn8W.... It can be plugged onto the Application Base board 3.0 at https://www.mouser.com/ProductDetail/Bosch-Sensortec/Application-Board-3.0?qs=sGAEpiMZZMuqBwn8WqcFUi.... Then you can download Development Desktop 2.0 GUI SW from our website at https://www.bosch-sensortec.com/software-tools/tools/development-desktop-software/ to start evaluation.

Thanks.

[Ashwath]

Hi Team 

  We have BNO055 brakout board. we belive this has BMM150+ gyro and accel sensor. Can we use this ? if yes do we need to use Non-fusionmodes - MAGGYRO  OR  Fusion modes -NDOF_FMC_OFF /NDOF   ? 

[FAE_CA1]

Hi,

Yes, you can use BNO055 NDOF mode. Please refer to Youtube video about how to calibrate the BNO055 magnetometer at https://www.youtube.com/watch?v=Nz4EozK4cPY for more information. When you place a magnet, or motor, or power line near a classical mechanical compass, the needle will go crazy. But BNO055 NDOF mode will maintain the heading when BNO055 is stationary.

Thanks.