Design and Implementation of a Virtual Reality Glove Device Final presentation – winter 2001/2 By:Amos Mosseri, Shy Shalom, Instructors:Michael Itzkovitch Adi Bar-lev Date :

General overview A device for real time sampling of a large number multi-state analog inputs Intended for use with a Virtual reality system Has an infinite number of other uses, such as games, human-computer interfaces, handicap assistance, and so on…

Hardware specifications Sampling 6 gloves, with 5 analog inputs each. Converting analog signals to digital,with 8 bits sampling resolution and 20Hz sampling rate. Communication with the computer via the RS232 serial port. Hardware dynamic range. Building 2 gloves.

Software specifications Designing a communication protocol. Programming the board’s firmware. Implementing a device driver API. Software dynamic range. Programming a demonstration application.

Hardware components PIC16F74 – micro-controller CMOS 4067 – analog multiplexer / demultiplexer AD7302 – dual 8 bit D/A MAX232 – RS232 driver / receiver

Work frequencies Micro-controller’s work rate – 16MHz (instruction rate – 4MHz) Internal A/D sampling rate – maximal rate: 44KHz, required rate: 20Hz * 32 = 640Hz. UART transmission rates , 38.4, 57.6, and 115.2Kbps. Signal rate over the bus - 4Mhz.

General hardware block scheme mechanical input RS232 Analog signal Digital signal V REF

WireUp diagram

Micro-controller burning A simple, cheap and easy to build programmer. Connects to the parallel port and uses a serial programming protocol. Assembling done using Microchip MPLAB Development environment.

Hardware user interfaces RS232 – computer - board connection, using only the basic 3 lines. No Flow control of any kind RJ45 – Analog source connection, custom designed wiring for the device’s needs Manual Reset switch – user-board switch

The protocol’s objectives Allow initialization data to pass from the client to the server. Allow data transmission. Allow real time, high speed transmission. Do all that, Efficiently.

General firmware block scheme

Firmware’s code – components Boot up on reset. And an Idle loop, waiting for requests Simple sampler. Single sample negotiation. Sample sequence negotiations. Initialization negotiation.

General device driver block scheme

Operations offered by the device driver Single sample Normal sample sequence Timer sample sequence Initialization –Default, GUI, file, direct –Cold / warm Software / hardware dynamic range

The demonstration application Direct activation of all of the API’s functions. Graphic display of the results. User friendly interface

Expansions Glove connection indicators (implemented). Software dynamic range (implemented). Additional analog input channels. Lower reference voltage. Protocol enhancement.

Conclusions The intermediating program. The wide verity of fields the project covered: –Electronics –Communication –Real time programming –Windows programming