DC MOTOR BI-DIRECTIONAL CONTROL QUESTION

I am looking for a circuit for DC Motor Control. I am wanting to control a motors direction via a switch as well as the time the motor turns or the number of revolutions it turns (whatever seems to be the easiest to implement). Can anyone give me pointers, diagrams, websites, etc. Thanks in advance.

For an entirely electronic design, consider using an h-bridge to drive your motor. The h-bridge's control signals are then driving by a microcontroller. The microcontroller monitors the rotation of the motor via an optical pickup, hall effect sensor, tach winding, etc. Your software can have an additional switch to "override" and control the motor direction. I have not thought about it, but you can probably come up with some arrangement of relays and switches to accomplish the same thing. I'd use method A.