Evaluation of hand-foot coordinated quadruped interaction for mobile applications

We evaluate the use of a foot-based input, coordinated with the hands/fingers, for the realization of fast (or simultaneous) multiple inputs for a hand-held device. We called the overall interaction technique the “quadruped user interface (QUI)” to reflect the main idea of making effective use of all four limbs of the human user. To investigate QUI’s utility, a foot-based interaction device was implemented by mounting a pressure sensor/switch in the sole of a shoe, acting upon a preset pressure threshold as a remote button device for the hand-held device. Experiments were conducted to assess the performance, usability and learnability of the proposed QUI on three representative mobile interactive tasks; namely, typing (e.g., for texting), object manipulation (e.g., for icon dragging), and making continuous control decisions (e.g., for game playing). Experimental results have shown that QUI generally did not exhibit the expected competent performance compared to the usual bimanual finger input, even with few days of practice. We highlight important considerations and lessons learned for interaction design with QUI, which one may consider as a viable future wearable interaction technique.