How to modify standard servos for continuous operation. This hack involves opening up the servo, removing the limit mechanics, and modifying the feedback pot. In his second tutorial Andrey shows how to add a rotatory encoder to the servo, for position feedback.
It will stand still with control pulse of around 1,5ms (mine likes 1515us; I guess you know how servo is controlled, right? Otherwise don’t hesitate to google for that useful knowledge). When the impulse shorter or longer it will start rotating. The bigger the difference between that “Zero Position” pulse length (1515us) and actual pulse length, the bigger will be the speed, but relation is highly unlinear.
Via the forum.