KY-031 knock sensor with ESP32

Supply 3.3-5 V Bus GPIO Measures vibration

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
S	Output (the part drives it)	D25	Short pulse on a knock: use an interrupt
VCC	Power	3V3	Middle pin, marked +. Use 3V3
GND	Ground	GND	Marked -

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 KY-031 datasheet, Pins S (signal), + (middle), -; spring contact with 10 kΩ resistor

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