These are a few fire fighting robots I've built for the St Louis Robotics FIRE mini comp.
The competition board is on the top right. It had a wall on the right side, as well as a line to the fire source.
The fastest time to put out the fire and return to the start point wins.

These robots were built with a mix of Inex electronic parts, and hand made parts.
They used either line following or
wall following to find their way to the fire source. Then fans to blow out the fire. The lower 2 entries used preprogrammed routines to know when to turn on the fans. The top used 2 LDR sensors to detect the fire, and turn on the fan.
Fire Fighting Robots