#include <Servo.h>
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int trigPin = 9;
const int echoPin = 10;

long duration;
int distinCM;

Servo radarServo;

void setup() 
{
  pinMode(trigPin, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
  radarServo.attach(11);
  lcd.begin();
    lcd.backlight();
 
}
void loop() 
{
  for(int i=0;i<=180;i++)
  {
    radarServo.write(i);
    delay(50);
    
    digitalWrite(trigPin, LOW); 
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH); 
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distinCM = duration*0.034/2;
    digitalWrite(4, LOW);   

  if(distinCM > 50)
  {     digitalWrite(2, LOW);
  digitalWrite(3, HIGH);

  lcd.clear();
  lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Safe !");
 
  delay(50);
 
 
   }

    if(distinCM < 50)
  { 
    if(distinCM >10)    {

        digitalWrite(4, HIGH);  
  delay(distinCM*1.2);                     
  digitalWrite(4, LOW);    
  delay(distinCM*1.2); 
    digitalWrite(2, LOW ); 
    digitalWrite(3, LOW ); 
   lcd.clear();
  lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Alert !!!");
 
  delay(50);

  }}
  if(distinCM < 10)
  {    digitalWrite(4, HIGH);   
    
    digitalWrite(2, HIGH);
  digitalWrite(3, LOW);
lcd.clear();
  lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Critical !");
 
  delay(50);
   }
  
 
  
    Serial.print(i);
    Serial.print("*");
    Serial.print(distinCM);
    Serial.print("#");
  }
  
  for(int i=180;i>=0;i--)
  {
    radarServo.write(i);
    delay(50);
    digitalWrite(trigPin, LOW); 
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH); 
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distinCM = duration*0.034/2;
     digitalWrite(4, LOW);   

  if(distinCM > 50)
  {     digitalWrite(2, LOW);
  digitalWrite(3, HIGH);

  lcd.clear();
   lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Safe !");
 
  delay(50);
 
 
   }

    if(distinCM < 50)
  { 
    if(distinCM >10)    {

        digitalWrite(4, HIGH);   
  delay(distinCM*1.2);                      
  digitalWrite(4, LOW);   
  delay(distinCM*1.2); 
    digitalWrite(2, LOW ); 
    digitalWrite(3, LOW ); 
   lcd.clear();
  lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Alert !!!");
 
  delay(50);

  }}
  if(distinCM < 10)
  {    digitalWrite(4, HIGH);   
    
    digitalWrite(2, HIGH);
  digitalWrite(3, LOW);
lcd.clear();
  lcd.print("Distance= ");
  lcd.setCursor (12,0); 
  lcd.print(distinCM);
  lcd.setCursor (0,1); 
  lcd.print("Critical !");
 
  delay(50);
   }
    Serial.print(i);
    Serial.print("*");
    Serial.print(distinCM);
    Serial.print("#");
  }
 
  
}