Measuring 0-3.3v on ADC pin?

ESPHome
1

I think I’ve stumbled onto the fact that the ADC pins on an ESP32 max out at 1v…

How can I accurately measure 0 to 3.3v on a pin?

A voltage divider but surely that would make the low end voltages very small?

2

Yeah, so what is the problem? :slight_smile:

Just use a voltage divider and do a small calibration for the factor (instead of just calculating it based on the resistor values).

3

Cool, thanks was just trying to make sure there was no other way to get it done…

4

Another way - I2C-connected ADC, f.e. widely used 4-channel ADS1115.
From my experience - significantly more precise comparing to ESP ADC input.

5

try with
attenuation: auto
or
attenuation: 12dB

6

Ah perfect! I will try that and see how I get on… Thank you!