I'm going to enter the 2003 Trinity College fire-fighting contest. I am starting with my entry from 2001 entry, using the same controller and a number of the same sensors.
I am replacing the drive system with the one used in Snuffy the Shamfire Slayer entered by Alex Brown in the 2001 contest. I have built & incorporated the new drive system, and it works like a dream. Thanks for sharing the info, Alex!
I plan on replacing the compass. It was unreliable and slow. I will get immediate heading data from a piezo gyro, and will correct the drift by adding two more GP2D02 distance sensors so I can calculate my angle relative to the wall (which is really what matters in the end).
I am going to replace my extinguishing system with a motor and prop designed for RC planes. On one hand, it feels like a cop out to go to a fan; but on the other hand the reason most people use them is that they work well. Part of the reason I'm changing is that the duster I was using to extinguish the flames is flammable if it comes out of the can slow enough, which I discovered after the contest last year.
I also plan on a surprise feature of the robot that I'm not sure if I will be able to get working, but if I do it should be a good entry for the Spirit of the Inventor prize (if they still do that).