int trigpin = 4;
int echopin = 5;
int Buzzerpin = 33;
float duration, distance;



void setup() {
 Serial.begin(9600);
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
}

void loop() {
digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);
  duration = pulseIn(echopin, HIGH);
  distance = 0.017*duration;

if (distance <= 100) {
    tone(Buzzerpin, 500);  
  }
   else if  (distance >100 , distance <=200) {
   tone(Buzzerpin, 300);
   }
   else {
    noTone(Buzzerpin);
   }
}