Hi everyone, saw a couple of pid control posts on this thread and figured I throw up a shameless (ok, maybe a bit shameful) plug for the arduino PID library I wrote a few months back: Arduino Playground - PIDLibrary
there's also been some healthy back-and-forth on this thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1226431507
the overhead may be a bit high for this application, maybe not. figured I'd let people know it existed.
Cheers