Fig. 5
(adapted from [19])
The basic principles of an accelerometer when measuring static acceleration. As the accelerometer is not moving (and is static), gravity is the sole force acting on the transducer. As such, the accelerometer readings represent the interaction between downward gravitational force relative to accelerometer position. These positions are upright, upside down, or perpendicular to the force of gravity (a). The continuous change in static acceleration is plotted over the 180° angles of the sensor including the three positions shown above (b)