🔐 Arduino Multi-Component Security System

A state-based security system built on the Arduino UNO (Elegoo kit) that integrates a membrane keypad, IR remote, and RFID-RC522 reader — with a Python GUI for real-time tag logging.

---

📋 Table of Contents

• Overview
• System States
• Hardware
  • Components
  • Wiring Diagram
• Software
  • Arduino Libraries
  • Python Dependencies
• Getting Started
  • 1. IR Code Calibration
  • 2. Upload Arduino Firmware
  • 3. Run the Python GUI
• Folder Structure
• Troubleshooting
• Author

---

Overview

This project implements a complete lock and tag-logging pipeline:

• A 4-digit PIN is entered on the keypad to lock the system
• The same PIN entered via IR remote unlocks it
• In the unlocked state, the RFID-RC522 actively listens for tags
• Each scan is logged to a SQLite database via Serial
• A Python/Tkinter GUI displays the tag database in real time

---

System States

┌─────────┐   Keypad PIN (#)   ┌────────┐   IR PIN (match)   ┌──────────┐
│ WAITING │ ─────────────────► │ LOCKED │ ──────────────────► │ UNLOCKED │
│  LED A  │                    │ LED B  │                     │ LED A+B  │
└─────────┘                    └────────┘                     └──────────┘
                                                                    │
                                                              RFID active
                                                              Tags logged

State	LED A	LED B	Keypad	IR Remote	RFID
WAITING	ON	OFF	✅ Set PIN	❌	❌
LOCKED	OFF	ON	❌	✅ Enter PIN	❌
UNLOCKED	ON	ON	❌	❌	✅ Active

---

Hardware

Components

Component	Elegoo Kit Part
Arduino UNO R3	Included
4×4 Membrane Switch Keypad	Included
IR Receiver Module + Remote	Included
RFID-RC522 Module	Included
2× LEDs (any color)	Included
2× 220Ω Resistors	Included
Breadboard + Jumper Wires	Included

Wiring Diagram

KEYPAD (4×4)
─────────────────────────────────────
 Row 1  →  Pin 9
 Row 2  →  Pin 8
 Row 3  →  Pin 7
 Row 4  →  Pin 6
 Col 1  →  Pin 5
 Col 2  →  Pin 4
 Col 3  →  Pin 3
 Col 4  →  Pin 2

IR RECEIVER MODULE
─────────────────────────────────────
 Signal →  Pin A2
 VCC    →  5V
 GND    →  GND

LEDs
─────────────────────────────────────
 LED A  →  Pin A0  →  220Ω  →  GND
 LED B  →  Pin A1  →  220Ω  →  GND

RFID-RC522          ⚠️  3.3V ONLY — do not use 5V
─────────────────────────────────────
 SDA    →  Pin 10
 SCK    →  Pin 13
 MOSI   →  Pin 11
 MISO   →  Pin 12
 RST    →  Pin A3
 3.3V   →  3.3V
 GND    →  GND

⚠️ Warning: The RC522 is a 3.3V module. Supplying 5V will permanently damage it.

---

Software

Arduino Libraries

Install all three via Arduino IDE → Tools → Manage Libraries:

Library	Author	Version
Keypad	Mark Stanley / Alexander Brevig	Any
IRremote	shirriff et al.	2.x (not v3/v4)
MFRC522	GithubCommunity	Any

Python Dependencies

pip install pyserial

tkinter and sqlite3 are included in the Python standard library.

---

Getting Started

1. IR Code Calibration

Every IR remote has different hex codes for each button. Before uploading the main sketch, you must map your remote's digit codes.

Quick calibration sketch:

#include <IRremote.h>
IRrecv irrecv(A2);
decode_results results;

void setup() {
  Serial.begin(9600);
  irrecv.enableIRIn();
}

void loop() {
  if (irrecv.decode(&results)) {
    Serial.println(results.value, HEX);
    irrecv.resume();
  }
}

1. Upload this sketch
2. Open Serial Monitor (9600 baud)
3. Press digits 0–9 on your remote and note the hex codes
4. Fill in the IR_CODES[10] array in firmware/security_system.ino

2. Upload Arduino Firmware

1. Open firmware/security_system.ino in Arduino IDE
2. Select Board: Arduino UNO and the correct Port
3. Verify IR codes are filled in (step 1)
4. Click Upload
5. Open Serial Monitor to confirm SYSTEM:READY is printed

Using the system:

• Type 4 digits on the keypad, press # to lock
• Press * on the keypad to clear your input
• Type the same 4 digits via IR remote to unlock
• Present an RFID card/fob — LEDs flash, tag is logged

3. Run the Python GUI

cd python
python gui.py

⚠️ Close the Arduino Serial Monitor before running the Python script — both cannot share the serial port simultaneously.

The script auto-detects your Arduino's COM port. If detection fails, edit line 72 in gui.py:

port = "COM3"       # Windows
# port = "/dev/ttyUSB0"  # Linux
# port = "/dev/cu.usbmodem14101"  # macOS

The GUI shows a live table of scanned tags:

Column	Description
ID	Auto-incremented unique ID
UID	RFID tag identifier (hex)
First Seen	Timestamp of first scan
Last Seen	Timestamp of most recent scan
Scan Count	Total number of times this tag was scanned

---

Folder Structure

arduino-security-system/
│
├── firmware/
│   └── security_system.ino      # Arduino sketch
│
├── python/
│   ├── gui.py                   # Tkinter GUI + serial listener
│   └── rfid_log.db              # SQLite database (auto-created)
│
├── docs/
│   └── wiring_diagram.png       # (optional: photo of your wiring)
│
└── README.md

---

Troubleshooting

Problem	Likely Cause	Fix
RFID not reading	RC522 wired to 5V	Move VCC to 3.3V pin
IR not recognized	Wrong hex codes	Re-run calibration sketch
Python can't open port	Serial Monitor still open	Close Arduino IDE Serial Monitor
Python can't open port	Wrong port	Edit port variable in gui.py
Keypad not responding	Row/col pins swapped	Double-check rowPins[] / colPins[]
Tags not logged to DB	State not UNLOCKED	Unlock system first via IR remote
IRremote compile error	Wrong library version	Downgrade to IRremote v2.x

---

Author

Rashad — Computer Engineering, ADA University (Class of 2026)
GitHub · LinkedIn