Seongkook Heo and Geehyuk Lee


We present an input technique on a touch screen that discriminates a gentle tap (Tap) from a strong tap (ForceTap) by utilizing accelerometer data available on many mobile devices. When a user taps on a touch screen, the device momentarily moves to the direction of the force that the finger applies to the screen. This movement can be measured by monitoring the acceleration of the device along the direction perpendicular to the touch screen. Finger taps with different force levels cause different acceleration patterns along the z-axis, which is the axis normal to the touch screen. By analyzing these patterns, a mobile device will be able to distinguish the meanings of touch screen inputs on the same touch point when the associated applied forces are different.