My $50 dollar tutorial robot has issues going in a straight line. (Not that it needs to in order to be a photovore.) I believe the servos rotate at slightly different speeds even though I modifed them by taking out the potentiometer and soldering fixed 1% tolerance resistors in its place. I used a 30 watt iron and a heatsink, could this have altered their resistance wtih too much heat? Could I have hit something on the PCB in the servo itself? I replaced the servo horns with wheels so they shouldn't be an issue.
So, should I be able to get a robot to go on a line on a straight surface without feedback or is it relativly normal to have some issues with this? Would it be easier to do this using an h-bridge and straight motors instead of servos or something?
PS: I'm using PWM (yes, I put some extra headers on the board to expose those microcontroller pins) rather than the timing loop provided in the tutorial.