For the past few days I have been working on a "smart" servo. Basically, I want the precision of a standard servo combined with continuous rotation and low costs.
The plan is: Put two brightness sensors on one of the inner gears and use them as a quadrature encoder to calculate the angle. This value is then sent to an arduino or directly used to reach a set position.
What I have done so far:
I decided to use a HK15138 Servo from Hobbyking because they are about the cheapest servos you can find at this size.