ForceKeyboard: Eyes-Free Text Entry With a Force Sensitive Soft Keyboard for Wearable Devices

As wearable devices such as smart watches, bands, and jewelry become more advanced and widespread, it is essential to address the challenges of text entry on their small interaction surfaces. This work introduces ForceKeyboard, a QWERTY soft keyboard for ultra-small devices, which utilizes touch location and force data to improve typing accuracy and speed. In a study involving 26 participants, we compared Force Keyboard with a Baseline keyboard that uses only tapping location data. The evaluation assessed performance across key sizes of 2.50, 1.75, and 1.00 mm in sitting and walking conditions. Participants performed eyes-free text entry tasks to reflect the occlusion and multitasking challenges of text entry on small wearable devices. Participants who used Force Keyboard achieved entry rates of 3.92, 3.57, and 2.77 words per minute, outperforming participants who used the baseline keyboard with 21%-168% higher speed and 16%-68% greater accuracy.