IMU 10DOF calibration and accuracy

Mitch_Faatz · September 16, 2020, 6:02pm

Does the calibration need to happen every time, or is there a way to save the calibration data and upload it to the sensor? Not sure how I can rotate the sensor in all 3 dimensions when it’s installed in my project.
I understand these become less and less accurate due to mathematical error rolling forward. How long will it be reasonably accurate? Two hours?

Baozhu · September 17, 2020, 12:49am

Sorry, There is no storage space on the sensor, you can store it in flash on the MCU.

Mitch_Faatz · September 17, 2020, 1:10am

I guess what I’m asking is “There doesn’t seem to be a function call in the API to SET or GET calibration data” so even if I store it on the MCU, there is no way to calibrate the unit, use the API to GET the calibration data and save it off, and then SET it to the IMU10DOF next time I start up?
Any idea on this question about how long the data can be reasonably trusted after startup? hour? two hours?

Baozhu · September 18, 2020, 1:05am

@Mitch_Faatz I read the code carefully, and the calibration is done through the following code.We are not sure if there is any other way to calibrate the sensor.

github.com

Seeed-Studio/Seeed_Arduino_IMU10DOF/blob/master/examples/IMU_10DOF_Test/IMU_10DOF_Test.ino#L286_L291


    mx = ((int16_t)(buffer_m[1]) << 8) | buffer_m[0] ;

    my = ((int16_t)(buffer_m[3]) << 8) | buffer_m[2] ;

    mz = ((int16_t)(buffer_m[5]) << 8) | buffer_m[4] ;



    Mxyz[0] = (double) mx * 1200 / 4096;

    Mxyz[1] = (double) my * 1200 / 4096;

    Mxyz[2] = (double) mz * 1200 / 4096;

}



void getCompassDate_calibrated ()

{

    getCompass_Data();

    Mxyz[0] = Mxyz[0] - mx_centre;

    Mxyz[1] = Mxyz[1] - my_centre;

    Mxyz[2] = Mxyz[2] - mz_centre;

}