Z-Tilez Project

Z-Tilez Website

About Z-Tilez

The Z-Tilez project is to investigate and develop a novel sensor design and computational architecture for an interactive floor space. A single z-tile is a flat tile made up of twenty pressure sensitive elements (known as prexels). Each prexel is hexagonal in shape and this allows the tiles to be constructed so that they interlock with each other allowing a complete floor of pressure elements to be assembled.

The electrical resistence of each prexel changes depending upon the pressure applied to it, and by reading these resistences a map of the pressure/weight distribution across the floor can be gained.

My work on Z-Tilez

Work on the Z-Tilez project began early in 2001, under the leadership of Mikael Fernstrom. I joined the project team in June 2001 as the first prototype Z-Tile was finishing production. The other members of the team at that stage were:

• Lisa McElligott
• Dave Carugo
• John Savage

Since then I have helped in the development of the Z-Tile, principally from the PC and software side. The tasks I have done so far include:

• Writing the software for the "black box" controller for the Z-Tile prototype. This software was written in Forth and assembler for the Hitachi chip and polled each prexel on the tile in turn and sent the pressure readings to a connected PC over the serial port. A C++ class to process those readings was also written by me to enable easy development of programs which use the Z-Tile.
• Creation of a simulation framework in C++ under Linux to test the workings of a floor of interconnected Z-Tilez. This simulator allows the design of a communications protocol between tiles and shows how a network of tiles with only one output connection could organise itself to ensure that data from all tiles gets output.
• Development of an object for the EyesWeb environment allowing multimedia in EyesWeb to use data from the Z-Tile prototype.

Final Year Project

Work on the Z-Tiles project is continuing with the development of a second generation tile much improved over the first. Instead of a second "black box" containing the microcontrollers for the raw data processing, this second version will have no less than 5 microcontrollers built into each tile.

My final year project, is to write the controlling software for each of these microcontrollers. Four of the microcontrollers are to be used for communication between tiles when the tiles interlock to form a continuous floorspace, while the fifth microcontroller performs many of the tasks undertaken by the blackbox on the original prototype - namely reading values from an analogue to digital converted and outputting those values. This time, the outputting is not done over a serial communication line, but by passing messages to the other microcontrollers on the same tile, and through them, quite likely to an adjacent tile.

The microcontrollers to be used in this development are both 8051 compatible microcontrollers produced by Cygnal Systems. The communication processors are the C8051F236 model, with the pressure-sensing microcontroller a C8051F206.