In this Project, ‘Digital Code Lock using AT89C2051’ LCD is used for display and a keyboard is used to input the keys. The project source code is written in C. Both the C files and hex files are given for download.

A Brief Description:

This project is written in C language. Its a simple project with efficient hacking prevention from Brute Force etc. The basic user lock is of 5 Digits and Master Lock is of 10 digits so its not easy for an intruder to break the lock unless you keep the code simple.

The input is taken from a 4×3 Keypad (please see the schematic for more information) and Display the user input on a 2×16 LCD. A pin is assigned as output for activating and deactivating the lock. For demonstration i have connected an LED to that pin.

User Side Working:

The user has two options either he/she can use its own 5 digit code or use the default 5 digit code. If user has to do setup his own code, then he has to enter “12345” and press ‘#’. After this.. controller will ask for 10 Digit master password which is preprogrammed in the controller. Entering master lock, user can enter the new 5 digit code for the lock and press ‘#’ to save it.

Using the Keypad:

Keypad has 12 keys (4×3) starting from 1,2,3,4,5,6,7,8,9,*,0,# (please see the schematic for layout). Numeric keys are used for entering numbers. ‘*’ is used as the Cancel key and ‘#’ is used as the Enter key.

Download File Information:

LCD.C – 4-Bit LCD Drivers

LCD.H – LCD function prototypes and other declerations

Lock.C – code for lock functioning

LOCK.H – lock function declerations

KEYPAD.C – Keypad drivers

KEYPAD.H – Function declerations

DELAY.C – Delay Functions

DELAY.H – Function Prototypes only

MAIN.C – Main function!

Digital Code Lock Schematic – PDF file of orcad schematic

Author: Ajay Bhargav

Download Circuit Diagram and Source Code in C

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