What I did with my project: I was making my robot to go around obstacles and end at the same spot that it would have ended up if it had not bumped into anything. I was using a simple Serial.print-ing, and after each time through the loop it'll print the current direction. The first time through it, it would go to "Foward" then "Right" once it made its first turn. Part of it was it recorded its direction. Problem: I used a switch loop and forgot to use "break;".
switch (direc)
{ // 8 - Forward, 4 - Left, 6 - Right, 2 - Back
case 8: // starts out 8, so changes to:
direc = 4; // 4.
case 6: // skips this:
direc = 8; // (skipped)
case 4: // It's 4, so now:
direc = 2; // 2.
case 2: // It's 2, so now:
direc = 6; // 6! Now it ends the switch loop and ends up with 6!!
default: ;
}
That's why it ended up w/ 6! That was my problem. The way I found out --> after almost each line I inserted a Serial.println of whatever just happened. Then I delayed it 3 seconds, so I could make sure it's right. Then I saw the error easily and figured out "I need to insert a 'break;'"!!
So basically, Serial debugging REALLY helped. I wouldn't have found the mistake without it. Serial print all variables discussed in the previous line, delay it enough time that you can check it's working, and Good Luck!!
Ps. I'll see if I can check the code.