arduino as pot

Hello.

I have a little project here, but i dont have a lot skills in hardware engineering.

My goal is to make arduino pro mini to convert pot readings to other scale in analog voltage. Im trying to make this stuff because i think 2k usd is not adequate price for 1 pot and some linkage to put it on. Pot are used to control height from ground on combine harvester header.

I know that pot should be producing voltage between 1.5 and 6.5 volts + difference should be 2 volts minimum from down to high.

As we know industrial pots are expensive and i have problems finding the one i need. But i have pot from cars accelerator pedal. Its making voltage from 1 to 8 volts if 12v supplied. It have 90 degrees effective range. Its ok for me i think.

So i would use voltage divider to read readings from pot.

Output are a bit harder. Now im thinking to put resistor ladder dac. The only problem i think now are that when arduino would switch digital pins voltage will jump. Does combine controller will feel it? Maybe i need to put on some capacitor after resistor ladder?

If you want a robust unit use an absolute rotary encoder, not a pot. You are talking
about a harsh agricultural environment where ordinary pots will simply corrode due to moisture.

These days magnetic rotary encoder chips like the AS5040 give 10 bit absolute
precision at a reasonable price if you can make the mechanical components.

Even industrial sealed absolute encoders are << 2k$

That are industrial pot at price about 150$. I mean 2k price was with some metal linkage to pots.

Even that pot works 2 years its ok, because i can get them almost for free.

Another option for an analog output voltage is low pass filtered PWM. There are online calculators to help with the filter design.

An intro to PWM and low pass filter:
PWM filter article

I have read about this too, but then i saw that filter will make some saw tooth. Resistor ladder would make more stable voltage i think. Only i cant figure out what will happen when arduino will switch pins, will voltage jump or it will do that quickly as even combine controller couldnt feel it.

Maybe i should add small capacitor after ladder so that would make voltage stable?

If your purpose is to convert one voltage range to another this is not a task for a microprocessor.

An Op-amp is what you want.