Improving Touchscreen Keyboards: Design issues and a comparison with other devices

Abstract

This study explored touchscreen keyboards using high precision touchscreen strategies. Phase one evaluated three possible monitor positions: 30, 45, and 75 degrees from horizontal. Results indicate that the 75 degree angle, approximately the standard monitor position, resulted in more fatigue and lower preference ratings. Phase two collected touch bias and key size data for the 30 degree angle. Subjects consistently touched below targets, and touched to the left of targets on either side of the screen. Using these data, a touchscreen keyboard was designed. Phase three compared this keyboard with a mouse activated keyboard, and the standard QWERTY keyboard for typing relatively short strings of 6, 19, and 44 characters. Results indicate that users can type approximately 25 words per minute with the touchscreen keyboard, compared to 17 WPM using the mouse, and 58 WPM when using the keyboard. Possible improvements to touchscreen keyboards are suggested. (Also cross-referenced as CAR-TR-515)