Discovering Quantities of Circular Motion of a Light-Emitting Toy Train Using a Smartphone Light Sensor

In recent years, smartphone sensors have been frequently used in educational demonstrations to improve students' understanding of certain physical kinematic topics. In particular, the sensors on modern smartphones enable students to use their phones as physics mini-laboratories, and they have been used to analyze objects' speeds and accelerations and to investigate the conservation of energy and magnetic field properties. As a particular example, one of the sensors on smartphones capable of being used to measure the speed and acceleration of light-emitting objects, and the value of g and spring constant, is the smartphone's light sensor. In similar fashion, we now outline how a smartphone's light sensor may be used to find the angular velocity, linear velocity, and centripetal acceleration of a light-emitting toy train moving on a circular track.