DualKey: Miniature Screen Text Entry via Finger Identification

Fast and accurate access to keys for text entry remains an open question for miniature screens. Existing works typically use a cumbersome two-step selection process, first to zero-in on a particular zone and second to make the key selection. We introduce DualKey, a miniature screen text entry technique with a single selection step that relies on finger identification. We report on the results of a 10 day longitudinal study with 10 participants that evaluated speed, accuracy, and learning. DualKey outperformed the existing techniques on long-term performance with a speed of 19.6 WPM. We then optimized the keyboard layout for reducing finger switching time based on the study data. A second 10 day study with eight participants showed that the new sweqty layout improved upon DualKey even further to 21.59 WPM for long-term speed, was comparable to existing techniques on novice speed and outperformed existing techniques on novice accuracy rate.