Abstract
The purpose of this study is to develop a relatively low cost system for recording of three dimensional motions, and the relationship between Fitts' Index of Difficulty(ID=log_2A/W) and movement time for some positioning movements was investigated. The system used three precision potentiometers, and it consisted of two single-turn potentiometers and a linear motion potentiometer. Each potentiometer gave electrical output signals corresponding to X, Y and Z coordinates of the stylus position. By use of this measuring system, it is possible to measure and record the displacement of hand movement in any direction as well as velocity and acceleration components. The correlation coefficient between ID and MT was 0.913,and the results supported Fitts' Law.
