Comparison of two touchpad-based methods for numeric entry

摘要

Small hand-held touchpads can be used to replace stylus-based digitizing tablets when the use of a stylus is not convenient. In text entry tasks where the writing surface is held in a hand the error rate becomes a problem. The small size of strokes compared to the width of the fingertip and the additional imprecision caused by the interaction of the pad and finger movements make input very imprecise. We describe a new improved clock-face based stroke system for entering numbers with a touchpad. In a 20-session user study with 6 users we found slightly better throughput of successfully entered numbers with the proposed new system. This advantage was mainly due to lower error rate with the new system. User preference similarly slightly favored the new system over an earlier straightforward proposal based on the clock metaphor.