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Dafydd Walters Robot

Dafydd Walters Dafydd@Walters.net

dafydd.jpg (20236 bytes) Microcontroller: 68HC11 w/32k of RAM

Drive System: Modified Hobby Servo

Base Type: Mekatronix Talrik Jr.

Sensors: Encoders, IR

Special Equipment: Water cannon

Main Purpose: Firefighting


My robot does not yet have a name, but it's hopefully going to be a fire fighter and compete in the 2001 Robothon. The base platform is a Mekatronix Talrik Junior Pro kit, which has a 68HC11A1 MPU board with 32KB RAM, and a pair of hacked servos for differential drive. To this base, I've added optical encoders to the wheels, a passive IR sensor to detect fire, and a small water canon built from a 3 volt water pump and an RC model fuel tank.

The wheel encoders work well and I've been able to achieve very good dead reckoning on hard floors. I followed the "Mobile Robots Inspiration to Implementation" recipe of using Hamamatsu P5587 photoreflectors mounted directly on the hacked servos, and cardboard discs with 48 black and white segments stuck behind the wheels.

The water canon, built around an Edmund Scientifics miniature pump, also works well, although the small water reservoir runs out very quickly. I'll need to check with a contest official to see whether "reloading" the water canon between runs is allowed.

The passive IR sensor is a 442-3 from Acroname. Since it is primarily intended for detecting humans, it is giving a lot of false readings, and may yet prove to be unsuitable for the contest. I may end up changing it for a UV sensor instead.

All the code I have developed for the robot so far has been written in Newton Labs' Interactive C. I'm currently in the process of moving my code to ICC11 for better performance and further development.