I'm trying to read analog value controlled by potentiometer. I receive different values for the same potentiometer position. For example, when I expect to receive 0, times to times I receive 1 and 2.
Code:
void setup() {
Serial.begin(9600);
}
void loop() {
int value = analogRead(A0);
Serial.println(value);
}
Scheme:
Serial console with values:
That is what they do. Good quality potentiometers are better, but they still have that.
Only in a simulation (such as in Wokwi simulation where you made that picture 
) it is perfect zero, but not in real life.
In software, you can add a filter or hysteresis.
Did you consider that there are only 1024 possible results of reading the A/D converter, while a 10k potentiometer has 10,000 possible positions?
Hi, @pavlo_makk_old
What is your application?
Thanks.. Tom.. 
Hi, @TomGeorge
I just want to test my BLDC motor. Use potentiometer as input for speed value of the motor
A capacitor from the wiper to groud will hep to bypasss noise. A starting point is the 0.1uF ceramic cap. It will not eliminate noise, but shoud reduce it.
Connect a 0.47uF capacitor from A0 to GND, if it's an electrolytic capacitor connect the + side to A0, see if that helps with "jitter".
As you can see, a wide range of values can be used. Many times one will see 2 or more caps connected in parallel. Each cap's value will allow it to bypass different frequencies. A 0.1uF ceramic cap will help to bypass higher frequencies. The 4.7uF is more effective at lower frequency.
Analysis and/or observation will indicate which to use in this case.
Hi, @pavlo_makk_old
So you want to calibrate the pot position for a given motor speed?
Have you built your project to see what the response is?
If not then do so, you may be OVER THINKING the system.
Tom..
In fact, unless it's a wire-wound potentiometer, it has a virtually infinite number of positions!
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