The Webdozer

The WebDozer, as the name implies, is a robotic bulldozer controlled via a webpage. A web server hosted on the MPC823 receives commands sent to it from a webpage via GET variables, which it in turn parses to direct DC-powered motors on the dozer.  The dozer contains an onboard infrared sensor which detects object distance.  This data is passed back to the webpage at the end of the query.

We interfaced into the MPC823 with Ethernet and a voltage based infrared sensor. We also connected two DC motors to the MPC823 through the use of testpoints and relays.  The DC motors are semi-pulse-width-modulated. In practice, one can solely apply a constant voltage to drive the motors in a specified direction.  The infrared sensor is connected to the MPC823 by the use of an ADC converter.

The most difficult part of the project was setting up the Ethernet. Once we were able to initialize the Ethernet controller on the MPC823 (Which was quite a task in and of itself), we then had to develop bare-bones implementations of IP, TCP, and HTTP encapsulators, each of which had many quirks of its own. It took a lot of testing and referencing published specifications for the networking protocols before things worked the way they were supposed to.