Re: How to use PID Control so that robot follows line smooth
re. testing. RobotC has a robot emulator called Robot Worlds, and there is a free trial, have a look at http://www.robotc.net/download/rvw/
PID may well be overkill for what you want to do, basic on/off control would probably be simpler to code, is that what you were trying in your other post? For PID you also need a measurable error range and I'm not sure that the light threshold really provides that, I may be wrong. Good luck.