Quote Originally Posted by shaiqbashir View Post

But one point that you made in your last post and that is that OpticaL Encoders sometimes donot prove to be enough faster in reacting than required. What if my robot speed is around 50RPM (i.e. quite slow) and i used a 10bit degree Optical Encoder, ?? I dont think it will be very slow in reacting? what do u say?
Why would an optical encoder be slow? Does light travel slower through an optical encoder? Did I miss something in physics class?
If you've got a slotted wheel, 1 inch in diamater with 10 slots in it and it rotates once per second, you'll get 10 pulses per second, or once pulse for every .31415926535897932384626433832795 inches travelled. If you get 90 pulses from the left wheel and 100 pulses from the right wheel, either you slow down the right, or speed up the left. Or you start driving both at the same time with the same pulse width, the left wheel gets 10 counts before the right wheel, so you slow down the left wheel a bit and speed up the right wheel until the counts are equal again, keep rechecking and rechecking...