🛡️ TimeGuard Access Shield — Password-Controlled Time-Restricted Machine Operation System

TimeGuard Access Shield is an embedded access-control system built using the LPC2148 microcontroller.
It combines secure password authentication, RTC-based scheduling, and an interrupt-driven configuration menu to ensure that only authorized users can operate a device — and only at allowed times.

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📸 Project Images

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🎥 Demo Video

🔐 Features

• 🕒 Real-Time Clock Display (Time, Date, Day)
• 🔑 Password-Based Authentication (Changeable Password)
• 👁️ Password Show / Hide Feature using Eye Toggle
• 🚪 Entry Access Only in Working Hours
• ⚙️ Admin Menu via EINT0 Interrupt
  • Change Date
  • Change Time
  • Change Password
  • Change Working Hours
• ⚡ Edge-Triggered EINT0 Interrupt Handling
• 🎨 LCD Custom Characters (Lock, Eye, Success, Warning)
• ❌ Blocks login after 3 failed attempts
• 📟 Full RTC configuration and live display

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🧩 Hardware Requirements

• LPC2129 / LPC2148 (or any LPC21xx)
• 16x2 LCD (HD44780)
• 4x4 Matrix Keypad
• EINT0 External Interrupt Switch
• RTC Module (DS1307 or compatible)
• Power Supply 5V
• Wires, Breadboard / PCB

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📁 Project Structure

/project
│-- main.c
│-- lcd.c / lcd.h
│-- rtc.c / rtc.h
│-- kpm.c / kpm.h
│-- system_init.c
│-- delay.c / delay.h
│-- arduino.c
│-- pin_connect_block.h
│-- types.h

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⚙️ Key Functionalities

1️⃣ Login Authentication

• Accepts 4-digit password
• Shows * by default
• Eye button toggles Show / Hide
• Supports backspace with C
• Auto-block after 3 wrong attempts

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2️⃣ Password Show / Hide Feature

A custom CGRAM eye icon is displayed at the right side.
Pressing the E key toggles:

• 👁️ Show Mode → Displays actual digits
• 🔒 Hide Mode → Displays * for all digits (including previously entered ones)

This ensures full privacy during password entry.

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3️⃣ Working Hours Access Control

System allows login only between Entry & Exit hours:

if ((EnHr <= cHour) && (ExHr >= cHour)) return 1;

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4️⃣ Admin Menu (via EINT0 Interrupt)

When EINT0 switch is pressed, system shows:

1 – Change Date
2 – Change Time
3 – Change Password
4 – Employee Working Hours
5 – Exit

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5️⃣ RTC Live Display

Continuously updates:

• Time → HH:MM:SS
• Date → DD/MM/YYYY
• Day → SUN to SAT

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🚀 How to Use

▶️ Startup

• Shows title screen
• Shows RTC continuously
• Press ENTRY switch → Password Login Screen

▶️ Admin Mode

• Press EINT0 button
• Press 1 to open admin menu

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🛠 Build & Flash

Use Keil uVision, Arm-GCC, FlashMagic.

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📸 LCD Icons (CGRAM)

• Lock icon
• Eye icon (show/hide)
• Success tick
• Warning sign
• Clock icon

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🏁 Conclusion

TimeGuard Access Shield ensures secure, reliable, and time-restricted machine operation — ideal for labs, workshops, and industrial environments.