Project Documentation

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

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

16x2 I2C LCD

VCC: Connected to 5V of Arduino UNO
GND: Connected to GND of Arduino UNO
SDA: Connected to A4 of Arduino UNO
SCL: Connected to A5 of Arduino UNO

12V Solenoid Lock

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

4X4 Membrane Matrix Keypad

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

5V Relay

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

Fingerprint Scanner

VCC: Connected to 3.3V of Arduino UNO
GND: Connected to GND of Arduino UNO
RX: Connected to D3 of Arduino UNO
TX: Connected to D2 of Arduino UNO

Buzzer

PIN: Connected to D5 of Arduino UNO
GND: Connected to GND of Arduino UNO

12V Power Supply

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

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() != F