ESP32 Capacitive Soil Sensor Read Problem

Solved
19

There are other more advanced functions to use with the ADC pins that can be useful in other projects.

  • analogReadResolution(resolution): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
  • analogSetWidth(width): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
  • analogSetCycles(cycles): set the number of cycles per sample. Default is 8. Range: 1 to 255.
  • analogSetSamples(samples): set the number of samples in the range. Default is 1 sample. It has an effect of increasing sensitivity.
  • analogSetClockDiv(attenuation): set the divider for the ADC clock. Default is 1. Range: 1 to 255.
  • analogSetAttenuation(attenuation): sets the input attenuation for all ADC pins. Default is ADC_11db. Accepted values:
    • ADC_0db: sets no attenuation. ADC can measure up to approximately 800 mV (1V input = ADC reading of 1088).
    • ADC_2_5db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1100 mV. (1V input = ADC reading of 3722).
    • ADC_6db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1350 mV. (1V input = ADC reading of 3033).
    • ADC_11db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 2600 mV. (1V input = ADC reading of 1575).
  • analogSetPinAttenuation(pin, attenuation): sets the input attenuation for the specified pin. The default is ADC_11db. Attenuation values are the same from previous function.
  • adcAttachPin(pin): Attach a pin to ADC (also clears any other analog mode that could be on). Returns TRUE or FALSE result.
  • adcStart(pin), adcBusy(pin) and resultadcEnd(pin): starts an ADC convertion on attached pin’s bus. Check if conversion on the pin’s ADC bus is currently running (returns TRUE or FALSE). Get the result of the conversion: returns 16-bit integer.

Maybe you should look at increasing the analogSetCycles() setting to smooth out the readings?

Pete.