int hz;
int distance = 2000;
int sensor;
void setup(){
  Serial.begin(9600);
  pinMode(A2, INPUT);
  pinMode(5,OUTPUT);////alarm pin
 

 

}


void loop(){
  
  
  sensor = 500;
  
  if (sensor<=distance){


    hz = ( 1000 ,0,distance,261,440 );
    ;

    tone(5,hz);
    
    Serial.println(hz);
  }


  else if (sensor>distance){
    noTone(5);
  }

}