Table of Contents
Automatic Door Lock
Author
Introduction
This project involves creating an automatic door lock system using Arduino, which integrates an RFID sensor and card to operate a mini servo motor connected to a door handle. Additionally, the system includes interactive features such as an LCD, buzzer, and RGB LED to provide feedback to the user regarding the successful reading of the RFID card.
The primary objective of this project is to enhance security and convenience by enabling users to unlock doors using RFID cards, eliminating the need for traditional keys. By incorporating feedback mechanisms like the LCD display, buzzer, and RGB LED, users can easily determine whether their RFID card has been recognized, enhancing the usability of the system.
The project aims to combine practicality with interactivity, offering users a seamless and intuitive experience when accessing doors. Whether it's for home security or office access control, the automatic door lock system provides a modern and efficient solution to traditional locking mechanisms.
General Description
Hardware Design
1. Component List
- Arduino Uno Board
- LCD 1602
- Micro Servo 9g
- Active Buzzer
- RFID-RC522 Reader
- Two RFID tags
- Breadboard
- 9v Battery
- Connecting wires and resistors
2. Price Table
| Component | Distributor | Quantity | Price |
| Arduino Uno Board | Optimusdigital | 1 | 40 RON |
| LCD 1602 | Optimusdigital | 1 | 17 RON |
| Micro Servo 9g | Optimusdigital | 1 | 35 RON |
| Active Buzzer | Optimusdigital | 1 | 5 RON |
| RFID-RC522 Module | Optimusdigital | 1 | 10 RON |
| Breadboard | Optimusdigital | 1 | 10 RON |
| 9v Battery | Optimusdigital | 1 | 10 RON |
| Total | _ | __ | 127 RON |
Obs: The prices are rounded to the nearest decimal.
3. Electrical Schematics
Software Design
I tried to design a system to control a servo motor based on RFID authentication, displaying an interactive feedback on an LCD screen. Key components include a servo motor, an LCD screen, an RFID reader, LEDs, and a buzzer.
Components and Libraries
- Servo Motor: Controlled using the Servo library.
- LCD Screen: Managed with the LiquidCrystal_I2C library.
- RFID Reader: Uses the MFRC522 library and SPI for communication.
- Indicators: Green and red LEDs, and a buzzer.
Operation
- Servo Motor:
- Locked position: 70 degrees.
- Unlocked position: 160 degrees.
- RFID Reader:
- Reads RFID tags and compares them to a predefined UID.
- LCD Display:
- Provides an interactive feedback for users.
- Indicators:
- Green LED: Indicates successful authentication.
- Red LED: Indicates failed authentication.
- Buzzer: Auditory feedback for failed attempts.
Algorithm
- Initialization:
- Set servo to locked position.
- Initialize LCD, servo, SPI, and RFID reader.
- Set up LED and buzzer pins.
- Main Loop:
- Display welcome message.
- Check and read RFID card.
- Compare read UID with predefined UID:
- Match & locked: Unlock door, update display and indicators.
- Match & unlocked: Lock door, update display and indicators.
- No match: Indicate failure with red LED and buzzer.
Scanning Code
I have used the code below in order to read the tags unique ID and register it in to the UID variable in my main program.
#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <MFRC522.h>
#define RST_PIN 9
#define SS_PIN 10
byte readCard[4];
byte a = 0;
LiquidCrystal_I2C lcd(0x27, 16, 2);//
MFRC522 mfrc522(SS_PIN, RST_PIN);
void setup() {
Serial.begin(9600);
lcd.init();
lcd.backlight();
while (!Serial);
SPI.begin();
mfrc522.PCD_Init();
delay(4);
mfrc522.PCD_DumpVersionToSerial();
lcd.setCursor(2, 0);
lcd.print("Put your card");
}
void loop() {
if ( ! mfrc522.PICC_IsNewCardPresent()) {
return 0;
}
if ( ! mfrc522.PICC_ReadCardSerial()) {
return 0;
}
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Scanned UID");
a = 0;
Serial.println(F("Scanned PICC's UID:"));
for ( uint8_t i = 0; i < 4; i++) { //
readCard[i] = mfrc522.uid.uidByte[i];
Serial.print(readCard[i], HEX);
Serial.print(" ");
lcd.setCursor(a, 1);
lcd.print(readCard[i], HEX);
lcd.print(" ");
delay(500);
a += 3;
}
Serial.println("");
mfrc522.PICC_HaltA();
}
Source Code
The following is the main program which implements the algorithm described above.
#include <Servo.h>
#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 10
#define RST_PIN 9
#define GREEN 6
#define RED 5
#define BUZZER 7
String UID = "C0 41 22 30";
Servo servo;
LiquidCrystal_I2C lcd(0x27, 16, 2);
MFRC522 rfid(SS_PIN, RST_PIN);
void setup() {
Serial.begin(9600);
servo.write(0);
lcd.init();
lcd.backlight();
servo.attach(3);
SPI.begin();
rfid.PCD_Init();
// pins
pinMode(RED, OUTPUT);
pinMode(GREEN, OUTPUT);
pinMode(BUZZER, OUTPUT);
}
void loop() {
lcd.setCursor(1, 0);
lcd.print("Welcome Home!");
lcd.setCursor(0, 1);
lcd.print("Scan your card");
if ( ! rfid.PICC_IsNewCardPresent())
return;
if ( ! rfid.PICC_ReadCardSerial())
return;
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Scanning");
Serial.print("NUID tag is :");
String ID = "";
for (byte i = 0; i < rfid.uid.size; i++) {
lcd.print(".");
ID.concat(String(rfid.uid.uidByte[i] < 0x10 ? " 0" : " "));
ID.concat(String(rfid.uid.uidByte[i], HEX));
delay(300);
}
ID.toUpperCase();
if (ID.substring(1) == UID) {
servo.write(70);
lcd.clear();
lcd.setCursor(0, 0);
analogWrite(GREEN, 255);
lcd.print("Door is locked");
delay(1500);
lcd.clear();
analogWrite(GREEN, 0);
lock = 1;
delay(1500);
servo.write(160);
}
else {
lcd.clear();
lcd.setCursor(0, 0);
analogWrite(RED, 255);
tone(BUZZER, 100);
lcd.print("Wrong card!");
delay(1500);
analogWrite(RED, 0);
noTone(BUZZER);
lcd.clear();
}
}
Conclusion
In this project I have got a first hand experience on how to work with arduino uno, protocols like I2C and SPI, sensors like RFID-RC522 and servo motor. Above all, I've managed to realize an arduino project which works and has a real life application for the first time.