The position of a ball was measured by using the touchscreen of a mobile phone during its rolling motion. The translational speed of the ball was determined using the recorded position and time data. The speed was also calculated by a conventional method. The speed values determined by the two methods were consistent, thus it was proven that a touchscreen could be used to detect position in physics experiments. Touchscreens of other smart mobile devices and touch tables can also be used for the same purpose.