It is used on a robot (which drives on a floor) indoors.

Thank you

Hi,

The data sheet of the OpenIMU300ZA claims that the resolution of the magnetic sensor is ~0.3 mGauss.
Do you have an approximation of how it relates to the resolution in degrees of the compass? (assuming that the imu is calibrated for hard/soft iron and located at sea level)

Do you have an approximation for the accuracy of the compass app (which also takes the gyro and accelerometer data into account)?

Thanks

Hi Li, Thank you for your help.
I was able to issue the mag-align procedure, but I still face some problems.

After I run alignment procedure and save the parameters to the eeprom, I get the following when sending 55 55 6D 61 01 07 81 C9 – Get stored values:
+++++++++++++ Mag-Align Defaults +++++++++++++
Hard-Iron: 0.19534, -0.03507
Soft-Iron Ratio: 0.90309
Soft-Iron Angle: -1.46192

+++++++++++++ Mag-Align Estimates +++++++++++++
Hard-Iron: 0.19534, -0.03507
Soft-Iron Ratio: 0.90309
Soft-Iron Angle: -1.46192

However, after rebooting the IMU, I get:
+++++++++++++ Mag-Align Defaults +++++++++++++
Hard-Iron: 0.19534, -0.03507
Soft-Iron Ratio: 0.90309
Soft-Iron Angle: -1.46192

+++++++++++++ Mag-Align Estimates +++++++++++++
Hard-Iron: 0.00000, 0.00000
Soft-Iron Ratio: 1.00000
Soft-Iron Angle: 0.00000

Will the firmware use the Mag-Align Estimates? If so, I think this is a bug.
I couldn't find how to set the Mag-Align Estimates to be equal to the Mag-Align Defaults, just the other way around with 55 55 6D 61 01 05 A1 8B

Apart from that, after I apply the alignment results, (when the Mag-Align Estimates are correct), the magnetometer data output is still the same. I plot the xMag - yMag and I get the same ellipse that I got without the alignment.
Is it a bug? or is it because the magnetometer output values are raw, and the alignment fix is done only to the heading calculation?

Last question:
Regarding the Heading output for this application - does a value of 0 means that the IMU is facing north? or value 0 is wherever the IMU was facing when it was turned on?

Was able to find these 2:
https://openimu.readthedocs.io/en/latest/algorithms/MagneticAlignment.html
https://github.com/Aceinna/docs_aceinna-dmu380/blob/master/tutorial/OpenIMU_Core/SerialMessaging.rst

But still, not sure how to read the returned data, for example from:
55 55 6D 61 01 07 81 C9 – Get stored values

Currently, the docs for both:
"Magnetic Alignment" - https://openimu.readthedocs.io/en/latest/mags/hardiron.html
and "Serial Messaging" - https://openimu.readthedocs.io/en/latest/tutorial/VG_AHRS/SerialMessaging.html
Are not available.

Anyway, I think I was able to send the commands over serial, but how should I interpret the returned data?