The latest keyboard version is an evolution of older one which was based on ATtiny2313 and could be connected to PC via PS/2 and was based on Attiny2313 microcontroller. Latest wearable keyboard is ported to at90usbkey demo board and can be connected to PC via USB.

Keyboard is able to produce all usual characters with few keys that are pressed in groups. It may be convenient to use it on special conditions like for portable computers, palmtops and so on. If you want to study it more John W. McKown provides project files and compiled firmware for free.

It seems that link to this project is dead, but you may download it from here. The key layout of this keyboard is similar to qwerty, with a thumb key to switch between the left and right sides of the keyboard.

It was intended for use with a wearable computer. With some modifications and processor upgrade it can be a great project to use in many wearable applications.