Prototype

Access Guard — IoT Access Control System

ESP32-based smart lock with keypad, RFID, GSM, and SD card user management

Code

Timeline

Jun 2026

Role

Embedded Systems Developer (Freelance)

Status

Prototype

About

A freelance capstone project — an embedded IoT access control system built on ESP32. Supports multi-factor authentication via 4x4 keypad (PIN/OTP), RFID cards, and GSM SMS commands. Features servo motor locking with auto-relock, emergency override switch, LCD status display, SD card user database, and RTC timestamp logging. Designed for small offices, storage rooms, and restricted areas requiring offline-capable access control.

Tech Stack

Microcontroller

ESP32 (Arduino Framework)

IDE

PlatformIO

Language

C++

Communication

GSM A7670E (SMS)

Peripherals

LCD I2C, Keypad, RFID, Servo, SD, RTC

Power

5V DC + Backup Battery

Features

Multi-Factor Authentication

4x4 matrix keypad with PIN and OTP entry modes
RFID card reader support (MFRC522)
GSM A7670E module for SMS-based OTP and remote unlock
User roles: admin, staff, guest with different access levels

Locking Mechanism

Servo motor lock with 0° (locked) / 90° (unlocked) positions
Auto-relock after 10 seconds
Emergency physical override switch
Reed switch for door-open detection

User Management & Logging

SD card CSV database: id, name, role, PIN, phone, enabled
RTC timestamp logging for all access attempts
LCD 20x4 display for status messages and prompts
Buzzer and LED indicators for access feedback