🔐 Numeric Code Authenticator | Embedded Systems Project

A microcontroller-based numeric PIN authentication system built using a 4x4 matrix keypad, LCD display, LEDs, and a buzzer. This system simulates a secure access mechanism, providing user feedback via both sound and visual output. Designed using C language and deployed on a Keil ARM environment.

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🎯 Features

• 🔢 User Input via 4x4 Matrix Keypad
• 📟 LCD Feedback for Success or Error States
• 🔊 Buzzer Alerts for Feedback (Success or Failure)
• 🔁 Retry Limit: Allows up to 3 incorrect attempts
• 🔐 Security Lock after 3 failed attempts

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⚙️ Components Used

Component	Description
Microcontroller	ARM-based (LPC 1768)
LCD Display (16x2)	For user feedback
4x4 Matrix Keypad	For PIN entry
LEDs	Optional for visual alert
Buzzer	Audio feedback for success/failure
Power Supply	5V regulated

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🧠 Working Logic

1. User is prompted to enter a 4-digit PIN using the keypad.
2. System checks the input against a predefined correct PIN.
3. Depending on the result:
   • ✅ Correct PIN:
     • LCD displays: "Access Granted"
     • Buzzer beeps once
   • ❌ Incorrect PIN:
     • LCD displays: "Incorrect, Try Again"
     • Buzzer beeps 3 times
     • Number of tries is incremented
4. After 3 incorrect attempts:
   • LCD displays: "Exceeded 3 Tries"
   • System locks further input

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🛠️ Setup & Programming

• Program written in C using Keil uVision IDE
• Simulated/tested using Proteus or real hardware
• Debouncing logic added for keypad
• LCD interfaced in 4-bit mode

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🧾 Sample Output

Enter PIN: [User inputs 1234]

-> If correct: LCD: "Access Granted" Buzzer: 1 short beep

-> If incorrect: LCD: "Incorrect, Try Again" Buzzer: 3 quick beeps

-> After 3 failed tries: LCD: "Exceeded 3 Tries" System: Locks input

ScreenShot