Digital Code lock using AT89C2051

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

A Brief Description:

This 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.

From user side:
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.

Circuit Diagram:

Circuit diagram of Digital Code lock using AT89C2051
Circuit diagram of Digital Code lock using AT89C2051

Download File Information:

  1. LCD.C – 4-Bit LCD Drivers
  2. LCD.H – LCD function prototypes and other declerations
  3. Lock.C – code for lock functioning
  4. LOCK.H – lock function declarations
  5. KEYPAD.C – Keypad drivers
  6. KEYPAD.H – Function declarations
  7. DELAY.C – Delay Functions
  8. DELAY.H – Function Prototypes only
  9. MAIN.C – Main function!
  10. Digital Code Lock Schematic – PDF file of orcad schematic

Download the source codes by clicking here

By Ajay Bhargav

Editorial Team
Editorial Team

We are a group of young techies trying to provide the best study material for all Electronic and Computer science students. We are publishing Microcontroller projects, Basic Electronics, Digital Electronics, Computer projects and also c/c++, java programs.

40 thoughts on “Digital Code lock using AT89C2051

  1. Hello Ajay Bhargav, which compiler did u use? I used SDCC but ur code seems to generate error. So cannot proceed for the asm files to be created.

  2. Nice project, but where do you store unlock key? I would put an EEPROM for key so you can change it programatically.

  3. which l.c.d u used in this kindly tell me the model and Vendor name of l.c.d or give me the data sheet if that L.C.D.

  4. sir,i implementd on proteus but hex file shws enter lock code,but it dont
    take 12345 or anythng as a password plz help

  5. i want to make the product still more reliable ,so please tell me how display the star(*)
    instead of displaying the number.please tell or send me the logic plz……………

  6. d hex file created for ds code s f 6kb bt d ic hs only 2kb f rom.. m facing serious problem here

  7. sir
    I want to know programming of AT89C2051 micro controller for digital lock code and detail description of digital lock code.

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