#define Trig_Pin 12
#define Echo_Pin 11
const int buzzer = 2; 

long duration;
int distance;

void setup() {
  // put your setup code here, to run once:
  pinMode(Trig_Pin, OUTPUT);
  pinMode(Echo_Pin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(Trig_Pin, LOW);
  delayMicroseconds(2);
  digitalWrite(Trig_Pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(Trig_Pin, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);

  duration = pulseIn(Echo_Pin, HIGH);
//  distance = speed * time
  distance =  duration*0.034/2;
  Serial.print("Distance : ");
  Serial.println(distance);

  if(distance < 45){
    digitalWrite(3, HIGH);
  }
  if(distance < 60){
    digitalWrite(4, HIGH);
  }
  if(distance < 90){
    digitalWrite(5, HIGH);
  }
  else{
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  }

  if(distance  < 45)
  {
    tone(buzzer, 1000); // Send 1KHz sound signal...
    delay(1000);        // ...for 1 sec
    noTone(buzzer);     // Stop sound...
    delay(1000);
  }


}