Has anyone used a circuit to protect the input pins whilst reading 0-3.3V analogue inputs from a remote potentiometer many meters away?
Yes, but what is the actual question?
Depending on your actual needs and your expected fault condition there might be different approaches
You could just use a 3.3V Zener diode or a opamp as voltage follower clamped at 3.3V or …
If you are supplying the pot with max 3.3V you may not need protection at all - unless you expect induced voltage or ESD.
So more info might be required.
3.3V provided by photon (does this require some protection?)
Long cable runs, so trying to make it unlikely that the proton is damaged by the installer in case of short etc. and also to be protected from noise.
The analog input signals will be used to control PWM
I think you could get away with no extra circuit, but a Zener diode is never wrong and nothing lost.
I’m sure we are refering to the Photon here.