#define BLYNK_TEMPLATE_ID "TMPL27CcT7Q_K"
#define BLYNK_TEMPLATE_NAME "Parking System"
#define BLYNK_AUTH_TOKEN "9smhtFRSy-SKrLboiFhwUUzExIQ2QCfq"

// Comment this out to disable prints and save space
LiquidCrystal_I2C lcd(0x27, 16, 2);

int IR1 = 4; // IR Sensor 1
int IR2 = 7; // IR Sensor 2
int Slot = 2; //Enter Total number of parking Slots
int flag1 = 0;
int flag2 = 0;

int trigPin = A0; // TRIG pin
int echoPin = A1; // ECHO pin
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
float duration_us, distance_cm;
float distanceInch;

void setup() {
  
  // configure the trigger pin to output mode
  pinMode(trigPin, OUTPUT);
  // configure the echo pin to input mode
  pinMode(echoPin, INPUT);
  pinMode(1,OUTPUT);
  pinMode(0,OUTPUT);
  lcd.init();
  lcd.backlight();
  pinMode(IR1, INPUT);
  pinMode(IR2, INPUT);
  lcd.setCursor(0, 0);
  lcd.print("   ARDUINO  ");
  lcd.setCursor(0, 1);
  lcd.print(" PARKING SYSTEM ");
  delay(2000);
  lcd.clear();

}

void loop() {

  if(digitalRead (IR1) == LOW && flag1==0){  
    digitalWrite(0, HIGH);
    delay(2000);
    digitalWrite(0, LOW);
    if(Slot>0){
      flag1=1;  
      if(flag2==0){ 
        Slot = Slot-1;
      }  
    }
    else{  
      digitalWrite(1, HIGH);
      delay(1000);
      digitalWrite(1, LOW);
      lcd.setCursor (0,0);  
      lcd.print("  SORRY :(  ");   
      lcd.setCursor (0,1);  
      lcd.print(" Parking Full ");   
      delay (1000);  
      lcd.clear();
      delay(3000);   
    }  
  }  
  if(digitalRead (IR2) == LOW && flag2==0){
    digitalWrite(0, HIGH);
    delay(2000);
    digitalWrite(0, LOW);
    flag2=1;  
    if(flag1==0){
      Slot = Slot+1;
    }  
  }  
  if(flag1==1 && flag2==1){  
    digitalWrite(0, HIGH);
    delay(2000);
    digitalWrite(0, LOW);
    delay (1000);    
    flag1=0, 
    flag2=0;  
  }  
  lcd.setCursor(0, 0);
  lcd.print("  WELCOME!  ");
  lcd.setCursor(0, 1);
  lcd.print("Slot Left: ");
  lcd.print(Slot);
  delay(1000);
  lcd.clear();
  delay(100);
  digitalWrite(IR1, HIGH);
  delay(1000);
  digitalWrite(IR1, LOW);
  delay(1000);
  digitalWrite(IR2, HIGH);
  delay(1000);
  digitalWrite(IR2, LOW);
  delay(1000);
  // 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);
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(echoPin, HIGH);

  // calculate the distance
  distance_cm = 0.017 * duration_us;
  distanceInch = distance_cm * CM_TO_INCH;
  // print the value to Serial Monitor
  lcd.setCursor(0, 0);
  lcd.print("Distance (cm)  ");
  lcd.setCursor(0, 1);
  lcd.print(distance_cm);
  delay(1000);
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Distance  (inch)");
  lcd.setCursor(0, 1);
  lcd.print(distanceInch);
  delay(1000);

  lcd.clear();
  delay(1000);
}