Capacitive soil moisture sensor with Arduino Uno R3

Wiring for the Capacitive soil moisture sensor v1.2 on the Arduino Uno R3 (ATmega328P, 5 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: 5 V from the 5V pin.

Test code (Arduino)

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

void loop() {
  long mv = (long)analogRead(14) * 5000L / 1023;  // AOUT on A0
  Serial.println(mv);
  delay(200);
}

Arduino board: arduino:avr:uno.

Questions

Which Arduino Uno R3 pins do I use for the Capacitive soil moisture sensor?

GND → GND, VCC → 5V, AOUT → A0 (PC0).

Does the Capacitive soil moisture sensor work with the Arduino Uno R3 at 5 V?

Yes: the Capacitive soil moisture sensor runs at 3.3-5 V and the Arduino Uno R3 uses 5 V signals, so no level shifting is needed.

Full Arduino Uno R3 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 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 Raspberry Pi Pico Teensy 4.1

Other parts on the Arduino Uno R3

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