The original stair climbing challenge was my first event with LRGoAA, so I was really looking forward to revisiting it. Unfortunately things didn't quite work as I intended.

This was the first event for LRGoAA that didn't take place in Ann Arbor (as far as I know, at least). We went down to Bowling Green, OH, to a coffee shop/bookstore suggested by Gabe. It was a nice place and not a bad drive, at least from my house.

I based my design on my original stair climbing bot, but with some crucial differences. Since my original attempt was very slow, I went for speed. Less gearing and only one movable axle instead of two, the theory was sound.

The implementation, however, left much to be desired. Some things I would do differently the next time around:

• I tried out one of my four-way touch sensor multiplexers for the first time and it didn't quite work as I expected. I was consistently not getting a reading for one of my touch sensors. Luckily for me I could rewire it at the event to merely use three sets of two opposing sensors.
• I had to reinforce the frame. Perhaps I made it a little too light.
• I really needed all-wheel drive. I had four axles but only two driven, one front and one rear. Due to weight shifts as the body moved up and down, the weight would come off of the driven axles, meaning I would get hung up.
• My back-and-forth-RCX weight-shifting mechanism tended to collide with the steps.
• Obviously, most of these problems were due to the fact that I don't have stairs to test on. For the next event I will build a set.

	A side shot, illustrating the mess of cabling on this bot. This is due to the six touch sensors and four motors in use. If I would have had enough time to rebuild the model, I would have focused more on cable management. The six sensors are arranged in three pairs: RCX front and rear, lifter up and down, and contact against the front of a step on both dual axle assemblies. The four motors are one to swing the RCX, one to lift the body, and two for drive. From the left, the first and third axles are powered. To operate, the bot drives forward until the frontmost touch sensor hits the step. The entire body is then lifted, leaving only the rear four tires on the ground. Once the body is sufficiently high, the bot drives forward, placing the forward axle assembly on top of the step. The RCX is then swung forward, shifting the CG and allowing the rear axles to be lifted up. After driving forward slightly, the RCX is swung back to the rear position and the cycle starts over. Coming down is similar.
	Here's the front. You can see more sensors and three of the motors. From the bottom, they are the front drive motor, the RCX swing motor, and the lift motor.
	A top view, with most of the cabling removed. This is looking down at the rear. The rear drive motor and lift motor are visible; the RCX motor is just visible below the RCX.