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Thanks for that confirmation, it gets me a long way to solving my issues.   Can I ask for more details about what the different config options for the magnetometer in MAGONLY and ACCMAG modes do. The datasheet discusses a "power mode" an "odr" an xy and z repetition, and a resolution for the magnetometer, but doesn't give much details. Nor does it explain what other options can be set, or what the defaults actually are. The section on the magnetometer (3.5.4) mentions data output rates, operation mode and power mode, but these don't clearly correlate to the table in 3.5.1 which mentionbs ODR and repetition but not operation mode. What exactly do the different operation modes mesn "low power", "regular", "enhanced regular" and "high accuracy", what are the advantages and disadvantages to each mode (are the more accurate oens noiser, or slower refresh rates?)? And is there any reason NOT to set the data output rate as high as possible, reduced accuracy perhaps? and any reason NOT to set the operation mode the high accuracy? Thanks ... View more

To clarify, if I enter the MAGONLY or ACCMAG mode by sending the appropriate I2C command to the BNO 055 then once in such a mode it will act as a normal magnetometer and accelerometer? I can handle calibration entirely externally and all the BNO 055 will do in these modes is ouput x-y-z values for the magnetic field vector, as it measures it (I can run de-distortion anti-hard/soft-iron code on my own device so long as I can get simple magnetometer and accelerometer readings) and the same x-y-z for what it feels gravity to be (with whatever effects accelerations may have in making this one inaccurate, although the robot is fairly slow to accelerate and turn so i doubt the inaccuracies here will matetr much)? In those non NDOF modes I should never need to worry about the BNO 055 deciding on a new calibration valeu set, as it won't have one? In those non NDOF modes I should never need to worry of the risk that the origin about which the mag field is defiend suddenly jumps (the way that orientation outputs can when calibrations change in an NDOF mode)? And between multiple different BNO 055 chips, and over time, so long as my algorithm running on my device to de-distort compass data is good enough then multiple devices will agree on what is North?   And although the BNO 055 contains a temperature sensor, slowly occuring chanegs in temperature shouldn't chnage anything about magnetometer readings so long as the actual magnetic field doesn't change? I really need to check if footnote 5 of page 48 of the datasheet "It is not possible to disable the automatic calibration which runs in the background" is still true, in any meaningful sense, when in a non-NDOF mode like ACCMAG or MAGONLY. Section 3.11.4 of the datasheet also talks of a soft iron calibration matrix, I assume in ACCMAG and MAGONLY modes that is not active, and any soft iron calibration, like hard iron, will be my problem to handle externally to the BNO 055? Some datasheets mention SIC matrices, some don't, I'm not actually sure whether the BNO 055 chips I've bought are more recent than the change on the datasheet. Either way, I assume this won't affect ACCMAG and MAGONLY modes in any way? If you can confirm whether all of the above is indeed the case then I am well on the way to solving my problems. Thank you ... View more

A hand compass placed beside where the BNO 055 sits in the robot tracks north well for part of a rotation, but very badly during a section of it. So I think there is a significant hard iron distortion going on. It is my understanding that hard iron distortions can be compensated for by putting the outputs of an x-y-z magnetometer through a few functions for which calibration constants must be calculated once for the device but which then remain constant. Any tips on getting a BNO 055 to behave like this? I know that other magnetometers can give plain x-y-z without self-calibrating constantly, but the pinout means I can't swap easily. So if the BNO 055 can be made to act like a simpler chip then that might be my best option. I'd like to get uncalibrated x-y-z magnetometry and uncalibrated x-y-z accelerometry (the accelerometer never needed calibrating in practice anyway, always gave good enough readings throughout) data out of it. Any resources about doing this? ... View more