Roy builds a custom controller for a customer, as usual in Roy’s eyes, a simple controller with switches to locate the alignment, Roy built a programmable controller, with seven push buttons, each with an led, and a stepper motor driver, as well as a potentiometer and a rotary encoder. As the Arduino Pro Micro does not have enough in/out pins to do all of this, Roy used a Resistor Ladder to read the Push buttons, this used 1 input instead of 7.
The Rotary encoder is used when programming the unit, while the potentiometer is used to set the speed of rotation of the potentiometer.
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The Proto-PIC Blog 
nice work, have posted this blog on the N Gauge Forum’s website.
Thank you Andy. This was a job to help one of customers. Design time of a few hours. We were thinking of playing around to make this DCC controlled which would vastly reduce the component count. Anyone interested?