int speakerPin=11;
int SW1 = 2;  
void wave(int pin, float frequency, int duration)
{
  float period=1/frequency *1000*1000;
  long int startTime = millis();
  while(millis()-startTime<duration)
  {
    digitalWrite(pin,HIGH);
    delayMicroseconds(period/2);
    digitalWrite(pin,LOW);
    delayMicroseconds(period/2);
  }
}
void setup() 
{
  pinMode(speakerPin, OUTPUT);
  pinMode(SW1, INPUT);
}
void loop()
{
  if(SW1==0)
  {
     wave(speakerPin,440,40);
     delay(25);
     wave(speakerPin,300,20);
     wave(speakerPin,540,50);
     delay(25);
     wave(speakerPin,440,20);
     wave(speakerPin,640,40);
     delay(25);
     wave(speakerPin,540,20);
  }
 
}