Keypad based simple electronic lock using 8051 microcontroller (AT89C51)

Summary

Developed By: 
Himanshu Choudhary

There are several electronic devices which require a security lock for their protection. This article describes a way to build an electronic lock with a four-digit password. A keypad, interfaced with 8051 microcontroller (AT89C51), is used to enter the password. The password and its status are displayed on an LCD screen.

Electronic Keypad Lock Project using 8051 Microcontroller (At89C51)

Description


A 4x3 matrix keypad and a 16x2 LCD have been used here. Keypad and LCD are very commonly used input & output devices, respectively. A four digit predefined password is specified in the microcontroller AT89C51's program. If the entered password from keypad matches with this password, then the lock opens and a message is displayed on LCD. Also an output pin is made high to be used for further purpose.

The connections in the circuit are as following: port P2 of microcontroller is used as data input port which is connected to data pins (7-14) of LCD. P1^0, P1^1 and P1^2 pins of microcontroller are connected to control pins RS, RW and EN of LCD. Port P0 is used to take input from keypad. P0^7 has been used as lock output pin of controller.
 
As the program starts, string ‘Enter Password’ is displayed on LCD. The keypad is scanned for pressed digits one by one. Every time row and column of the key pressed is detected and the resultant number is displayed on LCD. After the four digits are entered, they are compared with the pre-set password. If all the four digits match with set password, LCD displays ‘Lock Open’ and the lock output pin goes high. If the security code is wrong, ‘Wrong Password’ is sent to be displayed on LCD. The system gets locked if more than three attempts are made with wrong password to open the electronic lock. The system needs to be reset in such a case.

 

 

Circuit Diagram


Video

Code

This Code is only visible to Registered users. Please Login/Register

Code2

This Code is only visible to Registered users. Please Login/Register

Components

Presets | Variable Resistors
Preset
 
A preset is a three legged electronic component which can be made to offer varying resistance in a circuit. The resistance is varied by adjusting the rotary control over it. The adjustment can be done by using a small screw driver or...
AT89C51 Microcontroller, Atmel 89C51 Controller Image
AT89C51 Microcontroller

AT89C51 is an 8-bit microcontroller and belongs to Atmel's 8051 family. ATMEL 89C51 has 4KB of Flash programmable and erasable read only memory (...

16 x 2 LCD | 16x2 Character LCD Module
LCD

 

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications. A 16x2 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments...

Free Circuit Design & Simulation Tool by TI

Free Powerful Circuit Design & Simulation Tool by Texas Instruments

TINA-TI is a powerful circuit design and simulation tool. TINA-TI is ideal for designing, testing, and troubleshooting a broad variety of basic and advanced circuits, including complex architectures, without any node or number of device limitations.

Download It Here

Features:

Tina TI

TINA is an easy-to-use, powerful circuit simulation tool based on a SPICE engine. TINA-TI is a fully functional version of TINA, loaded with a library of TI macromodels plus passive and active models.

TINA-TI's new version 9 has changes from Version 7.0 in the following areas:

  • Schematic Symbol Editor (useable with the Macro Wizard) is included, so you can create your own symbols for imported SPICE macromodels.
  • Macros do not have to be from TI - you can import anyone's SPICE model now!
  • Does not require active or non-linear components for analysis (so you can now run a circuit using just passives).
  • TINA-TI includes Initial Condition and Nodeset components
  • TINA-TI includes Linear and nonlinear controlled sources (VCVS, CCVS, VCCS, CCCS), and the Controlled Source Wizard.
  • TINA-TI now allows WAV files to be used as stimulus (signal sources). You can play calculated waveforms on PC's multimedia system, and export calculated waveforms as a *.wav file.
  • TINA-TI has Multi-core processor support; this along with other optimizations makes simulations run 2-20 times faster.
  • Schematic file import/export in XML format
  • Block Wizard included for making block diagrams
  • TINA-TI has more SPICE models and example circuits included.
  • Circuits developed in TINA-TI 9 will work with TINA Industrial version 9.
  • TINA-TI Version 7.0 is forward compatible with Version 9, and version 9 supports saving schematics in version 7.0 format.
  • Available in English, Traditional and Simplified Chinese, Japanese, and Russian versions.

Download The Tool Here Free