// defines pins numbers
const int trigPin = 12;
const int echoPin = 13;
const int level4 = 8;
const int led1 = 2;
const int led2 = 3;
const int led3 = 4;
const int led4 = 5;
const int led5 = 6;
const int led6 = 7;
 
// defines variables
long duration;
int distance;
int safetyDistance;

void setup() {
 pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(level4, OUTPUT);
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(led4, OUTPUT);
pinMode(led5, OUTPUT);
pinMode(led6, OUTPUT);  
Serial.begin(9600); // Starts the serial communication

}

void loop() {
   // Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
 
// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
 
// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);
 
// Calculating the distance
distance= duration*0.034/2;
 
safetyDistance = distance;
if (distance <=5)
{
  digitalWrite(level4, HIGH);
}
else
{
  digitalWrite(level4, LOW);
}
if (distance <=5)
{
  digitalWrite(led6, HIGH);
}
else
{
  digitalWrite(led6, LOW);
}
if (distance <=10)
{
  digitalWrite(led5, HIGH);
}
else
{
  digitalWrite(led5, LOW);
}
if (distance <=15)
{
  digitalWrite(led4, HIGH);
}
else
{
  digitalWrite(led4, LOW);
}
  
 if (distance <=20)
{
  digitalWrite(led3, HIGH);
}
else
{
  digitalWrite(led3, LOW);
}
  if (distance <=25)
{
  digitalWrite(led2, HIGH);
}
else
{
  digitalWrite(led2, LOW);
}
if (distance <=29)
{
  digitalWrite(led1, HIGH);
}
else
{
  digitalWrite(led1, LOW);
}
// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);

}