(Arduino Study) Led on/off using piezo speaker knock.

source code

...

const int ledPin = 13;
const int knockSensor = A0;
const int threshold = 100;

int sensorReading = 0;
int ledState = LOW;

void setup(){
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
  
}

void loop(){
  sensorReading = analogRead(knockSensor);
  Serial.println(sensorReading);
  
  if(sensorReading >= threshold)
  {
    ledState = !ledState;
    digitalWrite(ledPin, ledState);
    Serial.println("Knock!");
  }
  
  delay(100);
}

---