Thanks for the questions, emdee.
The optointerruptor I stole off an old printer. It's pretty much just a phototransistor driven with an LED in a contained package with a slot. I use a clear CD blank with a black stripe to trigger the count. It's driven with a schmitt trigger circuit. I could have used an actual schmitt trigger chip, but I used what I had on hand (See attached pic).
The motor is a 12V also out of a printer. It's driven PWM by the arduino to control speed through a 30N06L Mosfet. The motor stops automatically when the desired # of turns is reached. I did have the motor controlled with a relay (as in picture attached), but figured if I had PWM, I could just send digital pin Low to stop motor.
Currently, there is no auto-traversing, and all layers traversed by hand. I have not wound any pickups yet as I am still building the final box for the monster. I'll also have a guide rail to manually set stops at the ends of the bobbin.
All of the buttons are controlled via a resistor network to limit input pins to the arduino.
I cannot take full credit. I borrowed alot of ideas from Pete Mills, who has a great blog here. Guitar Pickup Winder
