int a= 15;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(12, OUTPUT);
} 

void loop() {
  for(int i=0;i<a;i++){
  
  if(i>0&&i<=5){
    tone(12,10000);
    Serial.println(i);
    delay(1000);
  }
  else if(i>5&&i<=10){
    tone(12,5000);
    Serial.println(i);
    delay(1000);
  }
  else if(i>10&&i<=15){
    noTone(12);
    Serial.println(i);
    delay(1000);
  }
  };
}