Button module (KY-004) with ESP32

Supply 3.3-5 V Bus GPIO

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
S	Output (the part drives it)	D25	Signal: to a GPIO. Use INPUT_PULLUP too
VCC	Power	3V3	Middle pin
GND	Ground	GND	Marked - on the board

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

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

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

Joy-IT SensorKit X40 KY-004 key switch module, Pins signal, +V, GND; 10 kΩ resistor on the board

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