code-after-corrections

/*
   --------------------------------------------------------------------------------------------------------------------
   Example sketch/program showing how to read new NUID from a PICC to serial.
   --------------------------------------------------------------------------------------------------------------------
   This is a MFRC522 library example; for further details and other examples see: https://github.com/miguelbalboa/rfid

   Example sketch/program showing how to the read data from a PICC (that is: a RFID Tag or Card) using a MFRC522 based RFID
   Reader on the Arduino SPI interface.

   When the Arduino and the MFRC522 module are connected (see the pin layout below), load this sketch into Arduino IDE
   then verify/compile and upload it. To see the output: use Tools, Serial Monitor of the IDE (hit Ctrl+Shft+M). When
   you present a PICC (that is: a RFID Tag or Card) at reading distance of the MFRC522 Reader/PCD, the serial output
   will show the type, and the NUID if a new card has been detected. Note: you may see "Timeout in communication" messages
   when removing the PICC from reading distance too early.

   @license Released into the public domain.

  The circuit for LCD SCREEN:
  pin3 to grd with 220 ohm resister
   LCD RS pin to digital pin A0
   LCD Enable pin to digital pin A1
   LCD D4 pin to digital pin 5
   LCD D5 pin to digital pin 4
   LCD D6 pin to digital pin 3
   LCD D7 pin to digital pin 2
   LCD R/W pin to ground
   LCD VSS pin to ground
   LCD VCC pin to 5V
   10K resistor:
   ends to +5V and ground
   wiper to LCD VO pin (pin 3)

   RFID Circuit :
   Typical pin layout used:
   -----------------------------------------------------------------------------------------
               MFRC522      Arduino       Arduino   Arduino    Arduino          Arduino
               Reader/PCD   Uno/101       Mega      Nano v3    Leonardo/Micro   Pro Micro
   Signal      Pin          Pin           Pin       Pin        Pin              Pin
   -----------------------------------------------------------------------------------------
   RST/Reset   RST          9             5         D9         RESET/ICSP-5     RST
   SPI SS      SDA(SS)      10            53        D10        10               10
   SPI MOSI    MOSI         11 / ICSP-4   51        D11        ICSP-4           16
   SPI MISO    MISO         12 / ICSP-1   50        D12        ICSP-1           14
   SPI SCK     SCK          13 / ICSP-3   52        D13        ICSP-3           15
*/

#include <SPI.h>
#include <MFRC522.h>
// include the library code:
#include <LiquidCrystal.h>

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = A0, en = A1, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
#define SS_PIN 10
#define RST_PIN 9
int writeVal;
int greenLedPin = A2;
int redLedPin = A3;
int orangeLedPin = 6;
int buzzerPin = A4;

boolean chkConn = false;
MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class

MFRC522::MIFARE_Key key;

// Init array that will store new NUID
byte nuidPICC[4];
  boolean isValidating = false;
void setup() {
  Serial.begin(9600);

  SPI.begin(); // Init SPI bus
  rfid.PCD_Init(); // Init MFRC522
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  digitalWrite(buzzerPin, OUTPUT);
  for (byte i = 0; i < 6; i++) {
    key.keyByte[i] = 0xFF;
  }
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);

//  lcd.print("Welcome To GadgetProgrammer");
//  for (int i = 0; i < 26; i++) {
//    lcd.scrollDisplayRight();
//    delay(100);
//  }
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("GadgetProgrammer");
  delay(100);

  lcd.setCursor(0, 1);
  lcd.print(" Not Connected! ");
  //establishConnection();
}

void loop() {

  lcd.setCursor(0, 1);

  char retOutput;
  if (Serial.available() > 0) {
    retOutput = Serial.read();

    lcd.blink();
    if (retOutput == 'A') {
      chkConn = true;
      analogWrite(orangeLedPin,0);
      lcd.print("Swipe Your Card!");
    }
    if(retOutput == 'V'){
      analogWrite(orangeLedPin,1000);
      lcd.print("Validating Group");
      isValidating = true;
      delay(1000);
    }

    if(retOutput == 'S'){
      lcd.print("Validation Done!");
      glowGreenLed(1000);
      isValidating = false;
      delay(1000);
      }

  }
  if (chkConn && !retOutput != "") {
    if (retOutput == '1') {
      lcd.print("Attendance Done!");
      glowGreenLed(1000);
      delay(4000);
    }
    else if (retOutput == '0') {
      lcd.print("Network Error  !");
      glowRedLed(1000);
      delay(4000);
    } else if (retOutput == '2') {
      lcd.print("User Not Found!");
      glowRedLed(1000);
      delay(4000);
    } else if (retOutput == '5') {
      lcd.print("Network Error!");
      glowRedLed(1000);
      delay(4000);
    }
    //if not in validation process then swipe your card
    if(isValidating == false){
      lcd.setCursor(0, 1);
      analogWrite(orangeLedPin,0);
      lcd.print("Swipe Your Card!");
    }
    //lcd.clear();
    // Look for new cards
  }
  if ( ! rfid.PICC_IsNewCardPresent())
    return;

  // Verify if the NUID has been readed
  if ( ! rfid.PICC_ReadCardSerial())
    return;

  //Serial.print(F("PICC type: "));
  MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
  //Serial.println(rfid.PICC_GetTypeName(piccType));//Printing type of card

  // Check is the PICC of Classic MIFARE type
  if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&
      piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
      piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
    //Serial.println(F("Your tag is not of type MIFARE Classic."));
    return;
  }
  String s;
  for (byte i = 0; i < 4; i++) {

    nuidPICC[i] = rfid.uid.uidByte[i];

  }

  //Serial.println(F("The NUID tag is:"));
  //Serial.print(F("In hex: "));
  printHex(rfid.uid.uidByte, rfid.uid.size);
  Serial.println();
  lcd.setCursor(0,1);
  lcd.print("Reading Card...!");
  // Halt PICC
  rfid.PICC_HaltA();

  // Stop encryption on PCD
  rfid.PCD_StopCrypto1();
  delay(1000);
}


/**
   Helper routine to dump a byte array as hex values to Serial.
*/
void printHex(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? "0" : "");
    Serial.print(buffer[i], HEX);
  }
}

/**
   Helper routine to dump a byte array as dec values to Serial.
*/
void printDec(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? "0" : "");
    Serial.print(buffer[i], DEC);
  }



}
void glowGreenLed(int delaytime) {
  digitalWrite(orangeLedPin,LOW);
  digitalWrite(greenLedPin, HIGH);
  digitalWrite(redLedPin, LOW);
  tone(buzzerPin, 5000, 300);
  if (delaytime > 0) {
    delay(delaytime);
    digitalWrite(greenLedPin, LOW);
    noTone(buzzerPin);
  }
}
void glowRedLed(int delaytime) {
  digitalWrite(orangeLedPin,LOW);
  digitalWrite(greenLedPin, LOW);
  digitalWrite(redLedPin, HIGH);
  digitalWrite(buzzerPin, HIGH);
  delay(1000);
  tone(buzzerPin, 5000);
  //noTone(buzzerPin);
  if (delaytime > 0) {
    delay(delaytime);
    digitalWrite(redLedPin, LOW);
    noTone(buzzerPin);
  }
}
void glowOrangeLed(){
  analogWrite(orangeLedPin,100);
  delay(100);}