5k or 10k potentiometer for ADC reading

[daxliniere]

Hey gang!
I'm adding an analog joystick to an ESP32 project and have to option to choose 5k or 10k, linear or log.

What would be the advantages of using 10k over 5k, if any. Since it's a very simple voltage divider (0v and 3.3v), I can't see it would make any difference, but I'm wondering, if it was irrelevant, why would the company make two models?

Incidentally, the 5k linear I am using now behaves a little strangely, the middle position yields a stable reading of ~1880, rather than the 2048 (4096/2) that I was expecting it to read. Including esp_adc_cal.h seemed to improve the original behaviour, but this is still a little odd, right?


I'd love some input from someone more experienced than I with this.

Thanks and all the best,
Dax.

[jayben]

I don't hink you will see any difference; both are sufficiently low that there won't be any problems driving an ADC. The two versions are probably for compatibility with existing equipment, e.g. radio control model transmitters, which may use simple circuitry that requires a specific resistance.

With regard to the offset reading, this isn't surprising; it is either due to the joystick mechanics being slightly off, and/or inaccuracies in the manufacture of the potentiometer; they are produced in vast volumes for applications such as amplifier tone & volume controls, that don't need any precision at all.