Capacitive soil moisture sensor with NUCLEO-F401RE

Wiring for the Capacitive soil moisture sensor v1.2 on the NUCLEO-F401RE (STM32F401RE, 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 pin.

Test code (Arduino)

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

void loop() {
  long mv = (long)analogRead(PA0) * 3300L / 4095;  // AOUT on A0
  Serial.println(mv);
  delay(200);
}

Arduino board: STMicroelectronics:stm32:Nucleo_64:pnum=NUCLEO_F401RE. Plug the USB cable into the mini-USB port on the ST-LINK end. No button press is needed.

Questions

Which NUCLEO-F401RE pins do I use for the Capacitive soil moisture sensor?

GND → GND, VCC → 3V3, AOUT → A0 (PA0).

Does the Capacitive soil moisture sensor work with the NUCLEO-F401RE at 3.3 V?

Yes: the Capacitive soil moisture sensor runs at 3.3-5 V and the NUCLEO-F401RE uses 3.3 V signals, so no level shifting is needed.

Full NUCLEO-F401RE 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 Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

Other parts on the NUCLEO-F401RE

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