A crucial part of a tracking antenna system is the tracking itself. This is commonly performed by either DC or AC electric motors powered by a proprietary manual rotator controller box, which in turn is computer controlled via yet another proprietary interface, often on serial (RS232).
EARS plan to release a design for a modular rotator controller, with options for AC or DC motors, USB or Ethernet control, and seven segment or LCD status displays. There is a design document available at Google Drive, which contains the current plans.
If anyone is interested in joining the project then please comment below.