I've read through just about all of the threads relating to Arduino based focusers and building one is definitely something I'm going to have a go at. A 'version' I haven't seen yet is one using rotary encoders...so I'm guessing there's probably a reason for it! But here goes... My idea was to use 2 rotary encoders to control the stepper. One encoder for coarse focusing and the other one for fine adjustment. Something like this : In theory the coarse encoder would move the stepper a larger number of steps and the fine one would be single (or half) step. I did toy with the idea of using potentiometers (connected to the analogue inputs) instead of rotary encoders but thought the 360° rotation of the encoders would be more suitable. As my knowledge of programming is on a par with my guinea pig's, I'd like to know if the idea is feasible or not before attempting to blatantly copy and modify the various (rather brilliant) sketches and ideas from southerndiver357, yesyes, Gina etc. Any comments would be gratefully received.