No, they suggested a multi-turn potentiometer with an accompanying ADC, not a rotary encoder. This is not a bad suggestion at all.
Rotary encoders are continuous devices -- they turn and turn and turn. That's the up side. The down side is that if it's a quadrature encoder you don't know where the heck it is, only how far it's traveled. That means that every time you turn the power on you need to home the mechanism, which generally means slowly driving into a home switch until you notice a transition.
You can also get absolute encoders, but they're more rare and expensive
-- I don't believe you'll find one in the Digi-Key catalog.
Probably.
"Cycles per revolution", also known as "lines" for the way an optical encoder is made. There won't necessarily be any clicks. With a good quadrature encoder you can get four steps per cycle if you know what you're doing.
Yes and no. A 16 CPR quadrature encoder will give you a resolution of
1/64th of a turn, 80 CPR will give you a resolution of 1/320th of a turn.But your average gear may give you more than 1/64th of an inch backlash, unless you use a very fine tooth gear in which case you'll have to locate your rack and pinion very precisely, or use an anti-backlash pinion.
Do you know how to interpret the output of a quadrature encoder?
Just a 80 cycles per revolution encoder.
But I do think you'll do better with a string pot, or a gear and a multi-turn pot. ADCs are easier to read than encoders and you won't have to home the mechanism.