In my previous video ( • Building a magnetomete... ) we saw the construction of the Helmholtz coils. In this video we will see what must be done in addition, so that the calibrator can be used.
It is very important to put the sensor at the origin of the Helmholtz coils where the grad of the magnetic field is zero.
Let us 3D print a cubic sensor support.
The dimensions are such that an LSM303AGR sensor will be located exactly at the center of the cube.
To keep it in place an elastic band can be used.
Now let us 3D print a cube holder fitting the upper opening of the coils and holding the cube at the origin of the coils.
The cube can be oriented in any of 24 different orientations and the sensor will always be at the origin of the coils.
Now we may exercise a controlled field in any orientation of the sensor. The offsets follow the orientation of the sensor, whereas the background (Earth's) magnetic field stays at the same orientation. So it is easy to obtain as many equations as desired in order to calibrate the sensor by any method!
Негізгі бет Building a magnetometer desktop calibrator. Part two, using the calibrator.
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