Arduino Sketch 2

Knock Detector

Blow Detector

const int ledPin = 13;    

const int knockSensor = 0; 

const int threshold = 10;  // threshold value to decide when the detected sound is a knock or not

int sensorReading = 0;      // variable to store the value read from the sensor pin
int ledState = LOW;         // variable used to store the last LED status, to toggle the light

void setup() {
 pinMode(ledPin, OUTPUT); // declare the ledPin as as OUTPUT
 Serial.begin(9600);       // use the serial port
}

void loop() {
   sensorReading = analogRead(knockSensor);   

   if (sensorReading >= threshold) {
      ledState = !ledState; 

  digitalWrite(13, HIGH);   // set the LED on
  delay(100);              // wait for a second
  digitalWrite(13, LOW);    // set the LED off
  delay(10);              // wait for a second

  }

}