Movement Control Methods for Mobile Devices: An Empirical Study of Displacement Interfaces.

We conducted a user study to compare four displacement interfaces on mobile devices. An Android application was developed with four displacement methods: Soft Joystick, up-down-right-left Buttons, Tilt Sensors, and Dual Soft Joystick. The study involved 12 participants using the four interfaces to control an object from a starting point to a goal point in five trials having different paths. The time (s), number of wall hits, efficiency (%), and out-of-path movement (%) per trial were logged to compare the methods. There was a significant effect of Displacement Method and Path on each dependent variable (p <.005). The Button method had 95.5%, 90.4%, and 84.2% less out-of-path movement than the Soft Joystick, Tilt Sensors, and Dual-Soft-Joystick methods, respectively. Also, the number of times the object missed the path using Buttons represented 10% of the total, followed by Dual-Soft-Joystick with 20% of the total. Tilt Sensors was 2.8% faster than Buttons (second fastest) in time per trial. Button reported the best numbers for efficiency with 58.8% on average per trial being 12% more efficient than Soft Joystick as the second best. In addition, there were statistical differences in post hoc tests (p <.005) between Button, the best overall method, and the remain interfaces on all dependent variables results. The participants indicated Buttons as the most comfortable method overall and Tilt Sensor as the best and most promising method.