#define pinTrig 3
#define pinEcho 2
#define pinBuzz 13

long time, distance;

void setup() {
Serial.begin(9600);
  pinMode(12, OUTPUT);
  pinMode(pinBuzz, OUTPUT);
  pinMode(pinTrig, OUTPUT);
  pinMode(pinEcho, INPUT);
}

void loop() {
  digitalWrite(pinTrig, LOW);
  delayMicroseconds(2);
  digitalWrite(pinTrig, HIGH);
  delayMicroseconds(10);
  digitalWrite(pinTrig, LOW);

  time=pulseIn(pinEcho, HIGH);
  distance=time/58.2;

  if(distance<150 && distance >=1){
    tone(pinBuzz,200);
    delay(300);
    noTone(pinBuzz);
    digitalWrite(12, HIGH);
  }

  else{
    noTone(pinBuzz);
    digitalWrite(12, LOW);
  }
}