When it comes to calculating physical activity, nowadays a wide variety of tools is at our disposal.The phones used daily incorporate functions that calculate, for example, the number of steps taken throughout the day. Using the tools to set personal goals or to review which physical properties deviate. This work entails collecting data via a mobile camera using an application with the ability to measure luminance for the purpose of calculating heart rate. This thesis is done on behalf of Mobistudy, who wishes to calculate the heart rate during a common exercise test, the Queen’s College Step test. This is intended for use with a telephone held in the hand with the camera's index finger throughout the period, and the light intensity signal is affected by movement disturbances. The purpose of this work is to detect the heart rate in a way that is robust to these disturbances. The results were presented and, in the thesis, it was concluded that the majority of disturbances could be removed, but with the exception of a few tests.