Usability study of multiple vibrotactile feedback stimuli in an entire virtual keyboard input

With advances in information technology, people spend more time on touchscreen-based virtual keyboards than physical keyboards. However, typing on touchscreens usually lacks informative tactile feedback and anchoring references to locate the right keys, and thus requires more visual attention. Most prior tactile keyboard research used single stimulus pattern, which was not enough to recognize different keys. The purpose of this study was to investigate the usability of multiple vibrotactile feedback patterns in an entire virtual QWERTY keyboard input. A set of highly discriminable vibration patterns was designed and associated with different regions of a virtual keyboard to help users to locate the right keys. However, the number of stimulus patterns might also affect the typing performance. A user study was conducted to evaluate the effectiveness of the multiple vibrotactile feedback. The results showed that an appropriate number of stimulus patterns provided higher typing speed, higher typing efficiency, and lower error rate.