Positioning two connected motors

[DonRotolo]

How about controlling them from the same PWM output, using a Y cable? In other words, pretend they are one motor...

There will always be a small amount of 'fight' between them, but this can be made small enough to ignore.

PIC can be useful to make sure something moves to a very specific position, especially if you want it to get there quickly. However if this end position is fixed, a mechanical stop may be a wise choice.

In the past, we have had motors move something to one of three specific positions (start, halfway or all-the-way) using mechanical stops. The middle stop was actuated pneumatically, but could just as easily have been a servo. Didn't even need encoders, just limit switches (to avoid melting the motors)