RFID checker

RFID_alarm.cpp

#include <SPI.h>
#include <MFRC522.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define TRIG_PIN 6
#define ECHO_PIN 7

#define OLED_RESET 0  // GPIO0
Adafruit_SSD1306 display(OLED_RESET);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2


#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH  16

#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.
 
void setup() 
{
  pinMode(TRIG_PIN,OUTPUT);
  pinMode(ECHO_PIN,INPUT);
  Serial.begin(9600);   // Initiate a serial communication
  SPI.begin();      // Initiate  SPI bus
  mfrc522.PCD_Init();   // Initiate MFRC522
  Serial.println("Approximate your card to the reader...");
  Serial.println();
 
}

void distance_checker(){
  long duration, distanceCm, distanceIn;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN,HIGH);

  // convert the time into a distance
  distanceCm = duration / 29.1 / 2 ;
  distanceIn = duration / 74 / 2;

  Serial.print(distanceIn);
  Serial.print("in, ");
  Serial.print(distanceCm);
  Serial.print("cm");
  Serial.println();
  delay(250);
  if(distanceCm < 20 && distanceCm > 10){
    Serial.print("object is reached location!");
    Serial.println("\n");
    Serial.println(distanceCm);
  
    display.clearDisplay();
    display.setTextSize(1); // Draw 2X-scale text
    display.setTextColor(WHITE);   
  
    display.setCursor(33, 10);
    display.print("USER NEAR!");
  
  }else if (distanceCm < 10){
    Serial.print("Reached user!... RFID Enable mode");
    Serial.println("\n");
    Serial.print(distanceCm);
  
    display.clearDisplay();
    display.setTextSize(1); // Draw 2X-scale text
    display.setTextColor(WHITE);   
  
    display.setCursor(33, 10);
    display.print("RFID LOCK!");

  }else{
    Serial.print("OUTSIDE USER");
    Serial.println("\n");
    Serial.print(distanceCm);
  
    display.clearDisplay();
    display.setTextSize(1); // Draw 2X-scale text
    display.setTextColor(WHITE);   
  
    display.setCursor(33, 10);
    display.print("OUTSIDE");
  }
}

void loop() 
{
  display.display();
  delay(2000);
  distance_checker();
  
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) 
  {
    return;
  }
  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) 
  {
    return;
  }
  //Show UID on serial monitor
  Serial.print("\r UID tag :");
  String content= "";
  byte letter;
  for (byte i = 0; i < mfrc522.uid.size; i++) 
  {
     Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
     Serial.print(mfrc522.uid.uidByte[i], HEX);
     content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
     content.concat(String(mfrc522.uid.uidByte[i], HEX));
  }
  Serial.println();
  Serial.print("Message : ");
 
  content.toUpperCase();
  if (content.substring(1) == "0B EE CD 54") //change here the UID of the card/cards that you want to give access
  {
    Serial.println("Authorized access");
	display.clearDisplay();
    display.setTextSize(1); // Draw 2X-scale text
    display.setTextColor(WHITE);   
  
    display.setCursor(33, 10);
    display.print("RFID OPEN!");
	
    Serial.println();
    delay(3000);
  }
 
 else   {
    Serial.println(" Access denied");
	display.clearDisplay();
    display.setTextSize(1); // Draw 2X-scale text
    display.setTextColor(WHITE);   
  
    display.setCursor(33, 10);
    display.print("Reject!");
	
    delay(3000);
  }
}