Feasibility of a smartphone ambient light sensor as a revolution counter

  • Kari Van Vliet McMaster University


This paper explores the use of the ambient light sensor on an LG G3 smartphone as a tachometer. A method of detemining the RPM of a rotating chopper using variation in light intensity is presented and the accuracy of the results are examined under different lighting conditions and different distances between chopper blade and the sensor. The response time of the ambient light sensor is determined to be between 0.03 and 0.04s. The response time is used to determine the width of the chopper required to accurately determine the RPM of a bicycle wheel travelling 20km/h using the smartphone ambient light sensor system.


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