For some people, typing on a traditional keyboard may be difficult. However, if they can press a single key, then they are able to write text with ClickType. By cycling through rows of letters and predicted words, the user can select them by just clicking the space bar.
The POS library is used to (somewhat) intelligently predict upcoming words. A store of common word sequences (both in general, and for the user) is kept and referred to when deciding words to suggest.
Puck.js is an open source microcontroller button, which can be used with ClickType instead of using keyboard keys. This allows the user to be some way away from the computer keyboard.