First Measures in mV
Second Measures in g
Now, let's convert the mV into g. 1 g ≈ 9,80665 m.s-2
For each axis, calculation consists on:
The base values here are:
This test is highly recommended to identify the X-, Y- and Z-axis.
Then, the Earth attraction could be measured by rotating the sensor by 90°.
Another test is to move the sensor at constant pace on a table and watch what happens.
First conclusion is an accelerometer measures acceleration, that is, a change of speed.
Earth attraction is just one acceleration.