Investigating one-handed multi-digit pressure input for mobile devices

Abstract

This paper presents initial results from the design and evaluation of one-handed squeezing of a mobile phone: the application of force by each individual digit, and combinations of digits, of one hand as a means of interacting with a mobile device. As part of the evaluation we also consider how to alter the size of the interaction space to best suit the number of digits being used. By identifying which digits can accurately apply force both individually and in combination with others, we can then design one-handed, multi-channel input for mobile interaction. The results suggest that not all digits are equally accurate, and that some are more accurate when used in combination with others. Further, increasing the size of the underlying interaction space to suit the number of digits used improves user performance.

Side pressure for bidirectional navigation on small devices

“…Harrison et al [8] were probably the first to consider such hardware configurations with their handheld device that combines left, right and back 2-level pressure sensors to detect users' handedness. Very recently, Wilson et al investigated the physiological limits of such an approach by designing a mobile device augmented with seven continuous pressure sensors distributed on the sides and back of the device [23]. The placement of the different sensors is driven by the typical hand posture right-handed users adopt when holding the device with a single hand in portrait mode.…”

“…Those do not allow us to predict users' performance for bidirectional input with two pressure sensors located on one side of a smartphone, as controlling pressure input strongly depends on the user's hand posture and on the muscles involved [23]. However, these projects provide useful insights into the use of pressure as an input modality.…”

“…Like GraspZoom [13] and [23], SidePress uses two-sided (grasping type) pressure input, which is preferable to single-sided (pointing type) pressure input in a mobile context [20]. However, unlike GraspZoom, we overcome occlusion problems by squeezing the device along its y-axis rather than pinching it along its z-axis.…”

“…Figure 2 shows the two symmetric casings we have built to support both handedness and two different hand postures. Figure 2-(a) illustrates a right-handed user applying pressure with the two groups of digits <index, middle> and <ring, little>, that have been identified as particularly efficient for pressure control [23]. Figure 2-(b) illustrates the same user applying pressure with her thumb and palm.…”

Towards utilising one-handed multi-digit pressure input

“…Pressure input on mobile devices is highly accurate when using a single digit [6,10] and also when squeezing with different combinations of digits in concert [11]. One-handed pressure input is possible, by pressing into the screen [2,6] or tangentially across the screen [2].…”