First, the base. This is the original base. I was having problems with the motors not being powerful enough, the rubber coming off the rims, and the casters were bending and not operating correctly.
This is the new base. It is much larger, the wheels are bigger and geared down more and centered on the plate. The casters are far more rigid and I added two more. I have left two open axles (not shown) on the underside to add more PF motors if needed. Each wheel can have up to three XL PF motors. If you look at the side of the wheel housing there is a bit of axle sticking out. I left this in case I want to add a rotation sensor later. I also made the base more round to allow for easier turns so the corners won't get caught so much. The wheels are the old solid supercar style so they shouldn't crush under heavy weights, plus there are two on each side. The base is balanced so all six wheel touch the ground at the same time to distribute the weight better.
This is the light sensor communication hub I referred to a few days ago. The clear round bricks in the middle are to diffuse the light in all directions. The light on the sensor tends to shine directly forward and the bricks in the middle spread it.
I think I can overload this thing with PF and 9v motors. I have two HiTechnic IRLinks and I have been doing some tests to see if I can use them at full capacity. I learned that the IRLink is different than the IR Remote. The remote really fills the air with signal, but the IRLink shoots forward for a limited distance. As long as the IRLink is pointed directly at the receivers that you want to operate and all the stray and reflected signal is blocked, you can use two IRLinks in close proximity to each other. This way I can control up to 16 more motors on top of the 18 servos directly controlled by the NXT. I don't know if I will use that many motors, but it's nice to know that I can run up to 34 motors (WOW!) I can stack up the rotation sensors and creatively program the bot to save on ports too.
Here is a turret I have been working on too. It moves left, right, up and down. It has an ultrasonic sensor and an old RCX light sensor (behind the radar dish). This will be used to search for light sources, obstacles, edges of tables and such. There is one detail I'm not showing on purpose, but it is pretty cool and it's a surprise.
Anyway, you can see that I have been pretty busy. Progress is definitely happening, not as fast as I would like, but it is moving along.