I have a consumer equipment which has a knob and turning potentiometer to control the heating element. I have not taken apart the device yet to see the exact value of the pot but looking for some advices what is the best way to go with making this both arduino controlled and keeping the manual functionality intacted.
I come up with 2 ideas:
Stepper motor control (this would obviously work but there is not much space inside the case and mechanical elements can break over time)
Using some sort of FETs to emulate the potentiometer's resistance
If I want the arduino set values and the external pot values to be in synchron then the only way I see to do this is to completely take out the original pot from the circuit, hook up the arduino control there and then use (preferably the same) pot to do the same through the arduino so I can override the values from software when I like.
Also I would add an additional on/off switch to decide which value should be the relevant, the arduino's or the external pots. Obviously at reboots it would be always overwritten by what's the external pot giving to the Ardu at the beginning.