I Built this robot to explore the use of the Parallel Port for I/O operations. The purpose was to design a mobile base interfaced to the parallel port through a tether cable and controlled by a program running on the computer. The interface program comes in three versions: (1) C++ program written in Turbo C++ 3.0 (2) C++ program written in Visual C++ 6.0 (3) Visual Basic Program written in Visual Basic 6.0 The program has various buttons to make the robot move in all directions while getting feedback through the status port of the robots location. The robot consists of a H-bridge driver built from SPDT Relays. It has a 10-segment bar graph LED display for port status indication. The interface to the parallel port consists of 74367 chips. There is a 5V regulator for power to keep the voltage at a constant 5 volts for the relays and motors. The bot uses diferential drive stearing to get around. The construction materials used are plastic sheets and 3" foam rubber tires from Lynxmotion. The bread boards are from Radio Shack and the motors are from The Robot Store. I did not encounter to many problems since the robot was designed to be simple and cheap. There are a number of things I would do different in the design if I rebuilt it, but the current model performs its intended purpose. Next time I will not use relays because they are noisy and power hungry. I would choose different motors for the same reason as the relays. Future plans include computer control through IR and RF links, Sensor feedback, onboard micro-controller(s), sturdier design, more robust software, and whatever else I think up. My email is email@example.com if you have any questions/suggestions.