e-compass streaming test

[brucezhou]

Hi Sir, 

I have a question for the e-compass of my smart watches.

In factory, we have e-compass streaming test, could you give more explaination for this test ?

also in user mode, we can calibrate the e-compass via "8", how does it happen ?

Besides this, what does "low accuracy" and “high accuracy" mean ?

Thanks.

[brucezhou]

Thanks for the info, then after this, which means we did a calibration.

By the way, for the e-compass streaming test, could you give some explanation ?

"Record 20 test data.  Check one of axis test data with 5 times, there's no changes with test data value--> Fail  
There's test data value changes--> Pass"

[TomasVaverka · Accepted solution]

Hello Bruce,

Generally speaking, if you rotate a 3-axis magnetometer in 3D space slowly with Figure-8 motions, you can collect a lot of data points of [Bx, By, Bz]. If you plotted these data points in 3D you would find out that these data points form a sphere or an ellipsoid with the center shifted from the origin [0, 0, 0]. Then the offset would be [x0, y0, z0] so that you can subtract it to each data point and future data points so that the sphere or ellipsoid is centered at origin.

Best regards,

Tomas

[brucezhou]

Hi Sir, 

Thanks for the explaination of the "8" motion.

Could you explain something for self-test and stream test ?

Thanks.