#define echoPin 11
#define trigPin 12
int led_1=2;
int led_2=3;
int led_3=4;
int led_4=5;
int led_5=6;
int led_6=7;
int buzzer=13;
long duration;
int distance;
void setup()
{
  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);
  pinMode(buzzer,OUTPUT);
  pinMode(led_1,OUTPUT);
   pinMode(led_2,OUTPUT);
   pinMode(led_3,OUTPUT);
   pinMode(led_4,OUTPUT);
   pinMode(led_5,OUTPUT);
   pinMode(led_6,OUTPUT); 
}
void loop()
{
  digitalWrite(trigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin,LOW);
  duration=pulseIn(echoPin,HIGH);
  distance=duration*0.034/2;
  Serial.print("Distance:");
  Serial.print(distance);
  Serial.print("cm");
  delay(100);
  if((distance>=0)&&(distance<=4))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,HIGH);
  digitalWrite(led_4,HIGH);
  digitalWrite(led_5,HIGH);
  digitalWrite(led_6,HIGH);
  tone(buzzer,2000);
 }
  
 
if((distance>=5)&&(distance<=10))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,HIGH);
  digitalWrite(led_4,HIGH);
  digitalWrite(led_5,HIGH);
  digitalWrite(led_6,HIGH);
  noTone(buzzer);
 }
 if((distance>=11)&&(distance<=15))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,HIGH);
  digitalWrite(led_4,HIGH);
  digitalWrite(led_5,HIGH);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
 }
 if((distance>=16)&&(distance<=20))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,HIGH);
  digitalWrite(led_4,HIGH);
  digitalWrite(led_5,LOW);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
 }
    if((distance>=21)&&(distance<=25))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,HIGH);
  digitalWrite(led_4,LOW);
  digitalWrite(led_5,LOW);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
  }
  if((distance>=26)&&(distance<=30))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,HIGH);
  digitalWrite(led_3,LOW);
  digitalWrite(led_4,LOW);
  digitalWrite(led_5,LOW);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
 }
 if((distance>=31)&&(distance<=35))
 {
  digitalWrite(led_1,HIGH);
  digitalWrite(led_2,LOW);
  digitalWrite(led_3,LOW);
  digitalWrite(led_4,LOW);
  digitalWrite(led_5,LOW);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
 }
 if(distance>=36)
 {
  digitalWrite(led_1,LOW);
  digitalWrite(led_2,LOW);
  digitalWrite(led_3,LOW);
  digitalWrite(led_4,LOW);
  digitalWrite(led_5,LOW);
  digitalWrite(led_6,LOW);
  noTone(buzzer);
 }
}