Navigator

Rob Zumwalt and Mattieu Chardon built a mobile platform that navigates using odometry

 

(click on images to enlarge)

Two wheels steer and drive the platform. Each wheel is driven by a dc motor
The back of the motor turns 8 times faster than the wheel. The back is connected to a simple homemade quadrature encoder so that a computer can count wheel rotations and direction of rotation

The encoder consists of just a magnet and two hall switches, 90 degrees out of phase.

Ny counting pulses from the hall switch, the computer can keep track of wheel revs, and determine the position and orientation of the mobile platform.

Click the image to watch a quicktime movie of navigator in action. (6MB)

A report on the project.