An exploration of pressure input with bare finger for Mobile interaction in stationary and Mobile situations

Man-Ying Wang, Guihe Qin, Minghui Sun, Jian Zhao, Jun Qin

Abstract: Nowadays, most mobile devices provide two-dimensional inputs, such as taps and slides. Although pressure input, which only operates along the z axis as a single dimensional input, has long been investigated, it is separated from the x-y plane. Combining touchscreen sliding gesture with force input to enlarge the operation space is still under explored. Besides, compared with tablets, mobile devices require input with bare fingers, of which users have a poorer control than using a stylus, and have a special usage scenario, walking. How these factors influence the user performance are waiting to be answered. To fill the gap, we conducted an empirical study to explore users’ ability to control pressure on mobile devices. Participants were asked to perform pressure-based linear targeting in two postures (sitting and walking), with two types of visual feedback conditions (full and partial visual), and three confirmation methods (Dwell, Quick Release and Stroke). The results show that the number of pressure levels significantly affects error rate, movement time and number of crossings of selections. The pressure space can be divided into six levels with full visual feedback, while three levels with partial visual feedback, despite sitting or walking. The results indicate that Dwell is the most appropriate confirmation method. Based on our results, we also present a widget and discuss several applications for its potential use.