Ambiguous.org's Quinn Norton covers last weekend's Robogames event for the O'Reilly Network:
A sensor board coordinates data from two infrared controllers at 45° and 135° (angled to give some advanced data about the angle of the walls just in front of the robot). The sensor board also takes in data from a front-mounted sonar unit that tells the robot how far away the wall is (bumping a wall in the Trinity challenge is a penalty). Finally, there's a pair of line detectors pointing at the floor. These allow it to see the lines that mark the entrances to rooms, as well as the fire circle and the starting circle.
The last part of Larson's basic board kit is the CPU board, which pulls in data from the other boards, and spits out decisions to the motor.
Many of the decisions about what the sensors are seeing is farmed out to processors on the other boards, which come to an agreement using a subsumption architecture, the distributed decision-making architecture invented by Rodney Brooks in the 1980s. But at the top, the CPU board's Microchip PIC CPU (a 18F6621) uses a traditional maze-solving routine to map its way to the candle.
