Manu C Patel
Engineers in Huntsville, AL

6286220, Sep 11, 2001

Nov 30, 1999

9/451525

Robert Harrison - Poway CA
Manu C. Patel - Huntsville AL

Directional Robotics, Inc. - Huntsville AL

G01C 1726

33355R

A light-reflective device for determining positional information relative to an external magnetic field having a housing, a light-reflective compass assembly, a light generating and detecting assembly, a processor, and a display. The light-reflective compass assembly further includes a balanced disk magnet mounted on a compass card. The compass card includes a reflective pattern representative of the position of the housing with respect to the external magnetic field. The reflective compass assembly reflects light generated by the light generating and detecting assembly back toward the light generating and detecting assembly. The light generating and detecting assembly generates a signal representative of the position of the housing relative to the external magnetic field. The processor processes the signal received from the light generating and detecting assembly to determine the position of the housing relative to the external magnetic field and outputs the position to the display.