Project Documentation

Arduino-Based Smart Locker with Keypad, I2C LCD, and Fingerprint Sensor

Smart Locker Circuit Documentation

Summary

This document provides a detailed overview of a smart locker system based on an Arduino UNO microcontroller. The system integrates a 4x4 membrane keypad, a 16x2 I2C LCD, an R307 fingerprint sensor, a 12V solenoid lock, a 5V relay, and a buzzer. The locker can be unlocked using either a correct keypad code or a registered fingerprint.

Component List

Arduino UNO
- Description: Microcontroller board based on the ATmega328P.
- Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0
16x2 I2C LCD
- Description: 16x2 character LCD display with I2C interface.
- Pins: GND, VCC, SDA, SCL
12V Solenoid Lock
- Description: Electromechanical lock that operates on 12V.
- Pins: VCC, GND
4X4 Membrane Matrix Keypad
- Description: 4x4 matrix keypad for user input.
- Pins: R1, R2, R3, R4, C1, C2, C3, C4
5V Relay
- Description: Relay module for switching high voltage devices.
- Pins: Normally Open, Common terminal, Normally Closed, In, GND, VCC
Fingerprint Scanner
- Description: R307 fingerprint sensor for biometric authentication.
- Pins: VCC, TX, RX, GND
Buzzer
- Description: Piezoelectric buzzer for audio feedback.
- Pins: PIN, GND
12V Power Supply
- Description: Power supply providing 12V DC.
- Pins: +, -

Wiring Details

Arduino UNO

3.3V to Fingerprint Scanner VCC
5V to 5V Relay VCC and 16x2 I2C LCD VCC
GND to Buzzer GND, 16x2 I2C LCD GND, Fingerprint Scanner GND, and 5V Relay GND
A4 to 16x2 I2C LCD SDA
A5 to 16x2 I2C LCD SCL
D13 to 4X4 Membrane Matrix Keypad R1
D12 to 4X4 Membrane Matrix Keypad R2
D11 to 4X4 Membrane Matrix Keypad R3
D10 to 4X4 Membrane Matrix Keypad R4
D9 to 4X4 Membrane Matrix Keypad C1
D8 to 4X4 Membrane Matrix Keypad C2
D7 to 4X4 Membrane Matrix Keypad C3
D6 to 4X4 Membrane Matrix Keypad C4
D5 to Buzzer PIN
D4 to 5V Relay In
D3 to Fingerprint Scanner RX
D2 to Fingerprint Scanner TX

16x2 I2C LCD

GND to Arduino UNO GND
VCC to Arduino UNO 5V
SDA to Arduino UNO A4
SCL to Arduino UNO A5

12V Solenoid Lock

VCC to 5V Relay Normally Open
GND to 12V Power Supply -

4X4 Membrane Matrix Keypad

R1 to Arduino UNO D13
R2 to Arduino UNO D12
R3 to Arduino UNO D11
R4 to Arduino UNO D10
C1 to Arduino UNO D9
C2 to Arduino UNO D8
C3 to Arduino UNO D7
C4 to Arduino UNO D6

5V Relay

VCC to Arduino UNO 5V
GND to Arduino UNO GND
In to Arduino UNO D4
Normally Open to 12V Solenoid Lock VCC
Common terminal to 12V Power Supply +

Fingerprint Scanner

VCC to Arduino UNO 3.3V
TX to Arduino UNO D2
RX to Arduino UNO D3
GND to Arduino UNO GND

Buzzer

PIN to Arduino UNO D5
GND to Arduino UNO GND

12V Power Supply

+ to 5V Relay Common terminal
- to 12V Solenoid Lock GND

Code Documentation

/*
 * Arduino based Smart Locker with Keypad, I2C LCD, R307 Fingerprint Sensor
 * and 12V Solenoid Lock
 *
 * This code interfaces with a 4x4 membrane keypad, a 16x2 I2C LCD, an R307
 * fingerprint sensor, and a 12V solenoid lock. The system allows unlocking
 * the solenoid lock using either a correct keypad code or a registered
 * fingerprint.
 */

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Adafruit_Fingerprint.h>
#include <Keypad.h>

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Fingerprint sensor setup
Adafruit_Fingerprint finger = Adafruit_Fingerprint(&Serial);

// Keypad setup
const byte ROWS = 4; // four rows
const byte COLS = 4; // four columns
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {13, 12, 11, 10}; // connect to the row pinouts of the keypad
byte colPins[COLS] = {9, 8, 7, 6}; // connect to the column pinouts of the keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Relay and buzzer pins
const int relayPin = 4;
const int buzzerPin = 5;

// Predefined correct code
String correctCode = "1234";

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  finger.begin(57600);

  // Initialize LCD
  lcd.init();
  lcd.backlight();

  // Initialize relay and buzzer pins
  pinMode(relayPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(relayPin, LOW);
  digitalWrite(buzzerPin, LOW);

  // Display welcome message
  lcd.setCursor(0, 0);
  lcd.print("Smart Locker");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");
  delay(2000);
  lcd.clear();

  // Initialize fingerprint sensor
  if (finger.verifyPassword()) {
    lcd.print("Sensor found");
  } else {
    lcd.print("Sensor not found");
    while (1) { delay(1); }
  }
  delay(2000);
  lcd.clear();
}

void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Enter Code or");
  lcd.setCursor(0, 1);
  lcd.print("Scan Finger");

  // Check for keypad input
  String inputCode = "";
  char key = keypad.getKey();
  while (key != '#') {
    if (key) {
      inputCode += key;
      lcd.setCursor(0, 1);
      lcd.print(inputCode);
    }
    key = keypad.getKey();
  }

  // Check if the entered code is correct
  if (inputCode == correctCode) {
    unlock();
  } else {
    lcd.setCursor(0, 1);
    lcd.print("Wrong Code");
    delay(2000);
    lcd.clear();
  }

  // Check for fingerprint
  if (fingerprintMatch()) {
    unlock();
  }
}

bool fingerprintMatch() {
  finger.getImage();
  if (finger.image2Tz() != FINGERPRINT_OK) return false;
  if (finger.fingerFastSearch() != FINGERPRINT_OK) return false;
  return true;
}

void unlock() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Access Granted");
  digitalWrite(relayPin, HIGH);
  digitalWrite(b