One of my current projects is designing and building focusers for both my Takahashi and Celestron telescopes. I decided to base the design on myFocuserPro2. The design uses an Arduino as the core controller with optional controls and display. I chose to use a rotary encoder for manual focusing control since it's the closest to the action of turning the telescope's focus knob. For the display I went with a 1" 2-color OLED. Rather than the recommended direct motor connection I'm using a belt driven stepper motor.