Text entry using five to seven physical keys
Elliot Lockerman, Shuobi Wu, Ariel Rao, Jarret Lin, Neil Bantoc, Brad A. Myers · 2017
We designed, implemented, and evaluated a small physical keyboard, composed of four to five keys with a variety of mappings for the letters, along with one or two navigational function keys operated by the thumb. The small size allows it to be used for smartwatch text entry, and can be mounted on various body parts as a wearable keyboard. It is primarily used as an ambiguous keyboard, akin to T9, although a multi-tap mode is also present. Our keyboard layouts include Alphabetic, Collapsed QWERTY, Mnemonic (where letters are grouped based on their shapes), and Optimized (which minimizes the number of conflicts). In a between-users study, participants achieved an average of 15.4 words per minute (WPM) across all layouts, with one user with the Collapsed QWERTY layout reaching a top speed of 30.6 WPM after 4 hours of practice. User feedback was generally favorable.