@fedesilvi Just to give you an impression how bad the esp32 ADC is, I collected 10000 samples with the ESP32 ADC and an ADS7818 ADC taking values the same LM385 voltage reference. The absolute values differ, because of the different ranges (5V vs. 3.3V). The histograms are below: Edit: Adding a 10 nF capacitor close to the ESP32 ADC input and switching off WiFi improved the picture. The one above was WITH the capacitor. Without, the capacitor, it was worse (avg +/-100 readings)