Dimensions: 12 inches high, 8 inches in diameter Power: 12 "D" cell batteries Locomotion: Two unipolar stepper motors Brains: 2 Phillips 87C752, 1 Motorola 68HC11F1 Fire detection: 2 EG&G Thermopiles Fire extinguisher: Bilge pump and sprinkler head Rosie was built in three stages and designed to compete in the fire fighting robot contest. The first stage was a rolling base, then a navigation section, the third was the fire detection and extinguishing section. By building each as an individually functioning unit I was able to cut down my development time. The first stage consisted of two drive wheels mounted in a 8 inch diameter Plexiglas disk on the center axis. On a perpendicular axis were two casters. The stepper motors drove the drive wheels via a gear mounted to each. The steppers were "stepped" using a darlington transistor array with the stepper pattern counted off using a 87C752 microcontroller. For testing the microcontroller received a 4 bit speed code from a temporary board mounted with switches that was later replaced with a connection to the navigation unit. The navigation unit was built with a 68HC11F1 controller wirewrap board mounted on a 8 inch diameter Plexiglas disk. Three Omron optical proximity switches were also mounted on the disk. The proximity switches were used for wall detection at a range of 2 inches. A linear encoder and an optical detector were added to the base unit and attached to the navigation section. The linear encoder was mounted at the exact center of the base unit and was used to measure distance traveled. The navigation unit was mounted to the rolling base using standoffs. The navigation section sent spent speed and direciton information to the base unit. A four bit code (bit3=forward/reverse, bits0-2 time delay between stepper motor "steps") was used along with two interrupts (one for each motor). The units were tested together and could successfully navigate the floor plan described in the contest rules. The last stage built was the detection and extinguishing section. The detection was accomplished using two thermopiles mounted on rotating panels. The panels were rotated using 2 stepper motors. This last section used a 87C752 microcontroller to a) control the stepper motors that rotated the thermopiles, b) use the onchip A/D converter to measure voltage generated by the thermopiles, c) send a three bit direction code to the navigation module if a candle were detected, d) turn on a bilge pump if a signal were sent from the navigation controller. The candle was extinguished using water pumped from a bilge pump. The water was pumped to a sprinkler head that was attached to a linear actuator for moving the head back and forth. The battery pack and the water tank were a structural part of this section. Building the robot in three parts cut down on development time as well as providing myself with experience using different microcontrollers. Problems with Rosie: There were two basic design problems with the finished Rosie. The first was the fact that the robot was very slow. The water tank and 12 "D" cell batteries forced the steppers to be run at a very slow speed. The second problem was that the thermopiles did not have a very good range. A candle could only be found at approximately 12 inches. Email: Doug.Oda@stdreg.com