XKC-Y25 non-contact liquid level sensor with ESP32

Supply 5 V Bus GPIO Measures water level

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	VIN	Brown wire. Accepts 5 to 24 V: use VIN
OUT	Output (the part drives it)	D25	Yellow wire. On the -V version its HIGH level is the supply (5 V): use a voltage divider
GND	Ground	GND	Blue wire
MODE	Not wired to the ESP32	—	Black wire. Selects whether OUT is HIGH or LOW with liquid; see the seller sheet

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

void setup() {
  Serial.begin(115200);
  pinMode(25, INPUT);  // OUT
}

void loop() {
  Serial.println(digitalRead(25));
  delay(100);
}

XKC-Y25 seller datasheet, Supply 5 to 24 V; brown +V, yellow OUT, blue GND, black mode; senses through a non-metal wall up to 20 mm
XKC-Y25 seller datasheet, Versions: -V (voltage out), -NPN, -PNP; check which one you have

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.