Progress is accelerating! The Sharp GP2D12 infrared (IR) range finder arrived in the mail Friday and I was able to install it on a servo just in time for the SHARC meeting where I spent much of the day tweaking wall following software (it's coming along ok). I'm exceedingly pleased with this sensor. It seems very consistent and reliable for the limited testing I've done so far, making it much easier to detect wall distances.
Coincidentally, a major R/C expo was taking place at Wings Over the Rockies where we meet every 2nd Saturday of the month. So we got to meet a lot of great folks and, I hope, managed to recruit a few new members! :) Not to mention we saw loads of really cool R/C cars, airplanes, and helicopters, and got to show off George's web-controlled telepresence tank and other robots.
A package full of all kinds of goodies had arrived from BG Micro when I got back from the meeting. Sadly my secret weapon doesn't appear to be panning out. I'll tell you what it is once I'm sure. :)
That setback is no problem, because I had a major breakthrough: using a large lantern flashlight reflector with IR LED is surpassing my expectations. It appears to be relatively insensitive to candle height and, mounted on a servo, it can detect the presence and direction of a candle reliably at more than 260cm -- nearly double the maximum competition distance!
So the clock relentlessly ticks on quickly but things are starting to look a little more hopeful!