Project code

#define echo 3
#define trig 2
#define buz 7
 
long time;
int dist;


void setup() {

    pinMode(echo , INPUT);
    pinMode(trig , OUTPUT);
    pinMode(buz , OUTPUT);
    Serial.begin(9600);


}

void loop() {

  digitalWrite(trig , HIGH);
  delayMicroseconds(10);
  digitalWrite(trig , LOW);
  time = pulseIn(echo , HIGH);
  dist = time * 0.034 / 2;
  Serial.print(dist);
  Serial.println("  cm");
  delay(50);




  if(dist >=5 && dist<=16){

    digitalWrite(buz , HIGH);
  }
  else if(dist >16 && dist<=26){

    digitalWrite(buz , HIGH);
    delay(40);
    digitalWrite(buz , LOW);
    delay(20);
  }
  else if(dist >26 && dist<=36){

    digitalWrite(buz , HIGH);
    delay(60);
    digitalWrite(buz , LOW);
    delay(40);
  }
  else if(dist >36 && dist<=46){

    digitalWrite(buz , HIGH);
    delay(80);
    digitalWrite(buz , LOW);
    delay(60);
  }
  else if(dist >46 && dist<=56){

    digitalWrite(buz , HIGH);
    delay(100);
    digitalWrite(buz , LOW);
    delay(80);
  }
  else{
    digitalWrite(buz , LOW);
  }

}