I got the Arduino board replacement on Wednesday, and everything worked out fine. I can't tell if the ultrasonic range finder burned out a little or if it is just as crappy as it always was. I won't bother replacing it, though.
It turns out that the new rubber tires I got from the hobby store are a little too grippy. Because the tires require at least a little slippage when the robot turns (rotates), the robot can't turn at all because the tires simply don't slip on our floor.
So, last night, I decided to return to the hobby store to see if I could buy a different set of tires that maybe had better traction than the original tires but less traction than the ones I bought on Monday. I also decided to bring in the robot, along with my old Airport Extreme Base Station and MacBook Pro, so I could give a demonstration.
I got there just before closing, which was at 7 PM. A few customers came by to ooh and ah at the robot on the counter and ask questions, but extremely embarrassingly, I couldn't get the robot to run because I couldn't get it to connect to my base station. My MacBook Pro was able to connect, and it could see that there were about a dozen other WiFi stations in the immediate area, so it must have been interference that was causing the Edimax WiFi dongle on the Raspberry Pi to have problems.
Then, right at closing time at 7 PM, the Raspberry Pi finally made contact. I think the nearby Makerspace shop must have closed up and shut down its own WiFi access points, cutting down on interference. There were only the three store staff people left in the store, but I was able to run the robot around a bit and show them how it worked. I was also able to show them how the original tires slipped on the floor, so the guy who specialized in RC race cars was able to find a pair of racing tires that were softer than the original tires but harder than the tires he sold me earlier in the week.
I think the new tires will do nicely, but I also think that the best thing will be to switch tires depending on the surface the robot will drive on.
