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AN4509

Calculating tilt angles

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1.2.3

Tri-axis tilt sensing

With a 3-axis accelerometer, the user can use the Z-axis to combine with the X and Y axes

for tilt sensing in order to improve tilt sensitivity and accuracy (see Figure 5).

There are two ways to calculate 3 tilt angles in Figure 5. The first is to use basic

Equation 3

Equation 4

Equation 5

Figure 5. Tilt angles from a tri-axis accelerometer

The second way is to use trigonometric Equation 6 and 7 to calculate pitch and roll tilt angle,

which produces constant sensitivity over 360° of rotation, as shown in Figure 6.

Equation 6

Equation 7