I don't understand why it has to be a cable driven motor. I mean basicly what your doing is turning the TD. you can mount it on a stick and do that. I know about the sensor on the pedal but I figured that is to tell you where its pointing. Is there something im not seeing.
I haven't figured that out myself, maybe someone else has and can chime in. I would be really happy if they built it into the motor like the MK Universal Sonar so I don't have a cable to deal with. Maybe someday.