I'm trying to use a DC motor with servo-like controls, i.e., to specific a particular turn angle that will be reached, or to maintain constant rotation rate regardless of load. Typically, this requires using a PID feedback algorithm. A basic DC motor has no sensor that can drive a feedback system, but I've seen numerous posts online that seem to indicate that Arduino internals can serve this purpose.
Have any of you achieved precision control of a DC motor one way or another? What sensor/feedback system did you use? (I'm trying to drive rack and pinion steering.)