Two-level Force Input on TouchPad and the Effects of Feedback on Performance

Human fingers are accustomed to applying force in everyday activities and this dimension is not captured with today’s TouchPads. We developed a prototype TouchPad with force sensors capable of detecting force applied by a finger. We evaluated two-level force interaction by creating a modified Fitts’ task with two colored targets – one selected by light press and the other selected by heavy press. We evaluated the effects of modality of force level feedback on task performance time and error using audio and visual feedback and compared it to a no-feedback control condition. Results showed no difference in Fitts’ movement time between the various feedback conditions. Most participants preferred the simple audio feedback over other feedbacks. Many participants also commented that feedback helped them learn the force thresholds for each level but with practice they would prefer to have no additional force level feedback.