Extreme Typing: The Walk-On Keyboard

Web surfing and computer usage are usually sedentary activities, involving little physical motion or exertion. This project offers and alternate keyboard, on which the user walks (or jumps, or dances.) The keyboard surface itself is entirely passive. Detection of the "keypress" is done optically, by scanning a matrix of infrared beams and determining which have been broken. The control, decoding, and communications functionality is all handled by a Zilog Z80S183 microcontroller.

Each row or column beam currently requires two GPIO pins on the Z183, one to turn on the emitter, and the second to detect whether the IR beam is broken at the other side of the keyboard. The emitters and detectors are arranged into linear arrays that sit opposite each other on either side of keyboard (see block diagram). By having complete control over the emitters and detectors, the array can either be scanned one beam at a time, to conserve power, or arbitrary combinations of beams can be turned on simultaneously as desired. The current prototype simply scans through all the beams in sequential order to scan the keyboard array.

This design directly supports several packaging variations as well. It can be used to build large-scale "soft keyboards" with the texture of a flat punching-bag, for use by people with limited neuro-muscular control. And because the detection is entirely optical, it can also be wall mounted and hardened for use in environments like schoolyards or other public access terminals.

Design Motivation

The prototype of the Extreme Keyboard uses a Zilog Z80S183 embedded controller to provide opportunities for future expansion. Currently, all device communications is through one of the serial ASCIOs, however, it is a simple software addition to support the PS/2 PC keyboard interface. Furthermore, in addition to providing "basic" keyboard functionality, more of the utility of the keyboard function, such as audio feedback or terminal display control can be rolled into the Z183, making use of the mixed signal capabilities.

Project Photos