Capacitive soil moisture sensor with Raspberry Pi Pico

Wiring for the Capacitive soil moisture sensor v1.2 on the Raspberry Pi Pico (RP2040, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

Check before you power it on

• Supply: 3.3 V from the 3V3(OUT) pin.

Test code (Arduino)

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);
}

void loop() {
  long mv = (long)analogRead(26) * 3300L / 4095;  // AOUT on GP26
  Serial.println(mv);
  delay(200);
}

Arduino board: rp2040:rp2040:rpipico. If the board is not found, hold the BOOTSEL button while plugging in the USB cable.

Questions

Which Raspberry Pi Pico pins do I use for the Capacitive soil moisture sensor?

GND → GND, VCC → 3V3(OUT), AOUT → GP26.

Does the Capacitive soil moisture sensor work with the Raspberry Pi Pico at 3.3 V?

Yes: the Capacitive soil moisture sensor runs at 3.3-5 V and the Raspberry Pi Pico uses 3.3 V signals, so no level shifting is needed.

Full Raspberry Pi Pico pinout · Capacitive soil moisture sensor v1.2: all pins and data

The Capacitive soil moisture sensor on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Teensy 4.1

Other parts on the Raspberry Pi Pico

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