int speaker = 7;

void setup() {
  // put your setup code here, to run once:
pinMode (speaker, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
tone (speaker, 500,1000);
delay(250);

tone(speaker, 800,1000);
delay(250);

tone(speaker,800,1000);
delay(250);
}