Acceleration Measurements Using Smartphone Sensors: Dealing with the Equivalence Principle

TL;DR

This paper explores how smartphone sensors can measure acceleration in physics experiments, addressing the challenge of separating gravitational and inertial effects using the equivalence principle, with experimental validation.

Contribution

It demonstrates a method to correct smartphone acceleration data for gravity effects and validates it through experiments with a physical pendulum.

Findings

Successful correction of acceleration data for gravity effects

Comparison with video analysis confirms measurement accuracy

Discussion of sensor limitations in practical applications

Abstract

Acceleration sensors built into smartphones, i-pads or tablets can conveniently be used in the Physics laboratory. By virtue of the equivalence principle, a sensor fixed in a non-inertial reference frame cannot discern between a gravitational field and an accelerated system. Accordingly, acceleration values read by these sensors must be corrected for the gravitational component. A physical pendulum was studied by way of example, and absolute acceleration and rotation angle values were derived from the measurements made by the accelerometer and gyroscope. Results were corroborated by comparison with those obtained by video analysis. The limitations of different smartphone sensors are discussed.