How can I avoid jitter on Arduino analogRead()?

It is normal the value returned by analogRead() fluctuates up and down by 1-2.

I don't think that this can be dealt with in hardware, so you need your Arduino code to handle it.

Hysteresis i think it is called.

Mikael

This might help a little bit, but is not a real hysteresis: Think the current lowest two bits are "1" and the new ADC value increases by 1, then the third bit jumps, and cutting the lowest two bits has no effect, except for getting a jump of +4 in the result - not really what we want ;-)

A real hysteresis works like this:
- create a buffer variable
- calculate the absolute difference of the stored value to the newly read ADC value
- If the difference to the buffer variable is greater than x (the hysteresis) then update the buffer and use this value, otherwise discard the ADC value.
Use signed ints for this.

Code snippet:

#define HYSTERESIS 4
int16_t buffer;
int16_t adcvalue;

//in the loop:
adcvalue = analogRead(0);
if (abs(adcvalue - buffer) > HYSTERESIS)
buffer = adcvalue;

No warranty for the code, written on the smartphone and laying on the couch ;-)