void setup() {
    // Initiate the pseudo-random number generator
    randomSeed(analogRead(0));
}

void loop() {
 
    // Generate random pitch & duration
    int pitch = random(30, 5000);
    int duration = 1000 / (random(1000) + 1);

   //int pitch = 8000; //fixed freq
  // int duration = 20;

    // Play a tone to the digital pin PWM number 8
    tone(8, pitch, duration);
 

    // Make a pause
    delay(duration * 1.30);

    // Stop the tone playing
    noTone(8);
}