PASSWORD BASED DOOR LOCK SYSTEM

The aim of this project is to create a security system which asks for a

password before opening the door and opens the door only if the password

matches the programmed key. The door is opened by motors which in turn are

controlled by this security system.

Project overview:

Password Based Door Lock System

Hardware components required

1. ATMega 16 microcontroller

2. Basic calculator keypad

3. 2x16 LCD

Keypad and LCD are connected with microcontroller to make an easy man-

machine interface to make the system capable of performing the desired

function.

ATMega16 microcontroller: This is the brain of system which is

programmed to take input from user through keypad, perform the

desired operation and the display the appropriate message on the

provided 2x16 LCD.

Basi keypad: This is a 4x4 (having 4 rows and 4 columns) keypad which

is interfaced with microcontroller with its each key assigned a specific

no. or symbol defined in the program.

2x16 LCD: this is the liquid crystal display module capable of

displaying 32 characters in two rows (16 in each row). Microcontroller

displays characters on it while taking inputs from user and to display the

appropriate message to user.

Interfacing keypad with microcontroller

Keyboard Connections to PORTS

With matrix keypads 16 keys can function with 8 pins (4 rows and 4 columns)

of microcontroller’s either same or different ports as convenient.

Scanning and identifying the key pressed

Function to identify a key pressed

//connect colum with lower nibble and rows with upper nibble

#define key_port PORTA

#define key_ddr DDRA

#define key_pin PINA

unsigned char keypad[4][4]={'7','8','9','/',

'4','5','6','*',

'1','2','3','-',

'c','0','=','+'};

char takekey()

{

unsigned char row,colum;

char key;

key_ddr=0xf0;

key_port=0xff;

do

{

key_port&=0x0f;

colum=(key_pin&0x0f);

}while(colum!=0x0f);

do

{

do

{

_delay_ms(1);

key_port&=0x0f;

colum=(key_pin&0x0f);

}while(colum==0x0f);

_delay_ms(1);

key_port&=0x0f;

colum=(key_pin&0x0f);

}while(colum==0x0f);

while(1)

{

key_port=0xef;

colum=(key_pin&0x0f);

if(colum!=0x0f)

{

row=0;

break;

}

key_port=0xdf;

colum=(key_pin&0x0f);

if(colum!=0x0f)

{

row=1;

break;

}

key_port=0xbf;

colum=(key_pin&0x0f);

if(colum!=0x0f)

{

row=2;

break;

}

key_port=0x7f;

colum=(key_pin&0x0f);

row=3;

break;

}

if(colum==0x0e)

key=keypad[row][0];

else if(colum==0x0d)

key=keypad[row][1];

else if(colum==0x0b)

key=keypad[row][2];

else

key=keypad[row][3];

return(key);

}

Interfacing 2x16 LCD with microcontroller (in 4 bit mode)

LCD interfacing with atmega 16

LCD functions in accordance with above figure:

#define en PA2 // enable signal

#define rw PA1 // read/write signal

#define rs PA0 // register select signal

void lcd_cmd(unsigned char cmd)

{

DDRA=0xff;

PORTA=0;

PORTA=cmd&0xf0;

lcd &=~(1<<rs);

lcd &=~(1<<rw);

lcd |= (1<<en);

_delay_ms(1);

lcd &=~(1<<en);

_delay_ms(1);

PORTA=((cmd<<4)&0xf0);

lcd &=~(1<<rs);

lcd &=~(1<<rw);

lcd |= (1<<en);

_delay_ms(1);

lcd &=~(1<<en);

_delay_ms(1);

return;

}

void lcd_data(unsigned char data)

{

PORTA=(data&0xf0);

lcd |=(1<<rs);

lcd &=~(1<<rw);

lcd |= (1<<en);

_delay_ms(1);

lcd &=~(1<<en);

_delay_ms(1); // delay to get things executed

PORTA= ((data<<4)&0xf0);

lcd |=(1<<rs);

lcd &=~(1<<rw);

lcd |= (1<<en);

_delay_ms(1);

lcd &=~(1<<en);

return ;

}

void ini_lcd(void)

{

_delay_ms(5);

lcd_cmd(0x02);

_delay_ms(1);

lcd_cmd(0x28);

_delay_ms(1);

lcd_cmd(0x01); // clear LCD

_delay_ms(1);

lcd_cmd(0x0E); // cursor ON

_delay_ms(1);

lcd_cmd(0x84);

_delay_ms(1);

return;

}

Description:

This system works as follows to open the door:-

i. Asks for the visitor to enter the Password.

ii. If entered password matches the programmed one then it glows the

indicator and run the motors to open the door otherwise takes the

programmed action.

Main Program:

#include<avr/io.h>

#include<util/delay.h>

#include"keypad.h"

#include"4bitlcd.h"

void main()

{

unsigned int pass=5555,key,key1,ch1;

unsigned char ch=0,i,w[]="wrong password",E[]="ENTER PASSWORD";

DDRD=0XFF;

DDRB=0XFF;

_delay_ms(500);

ini_lcd();

while (1)

{

key=0;

ch=0;

lcd_cmd(0X80);

for(i=0;i<15; i++)

lcd_data(E[i]);

lcd_cmd(0xC0);

while(ch!='=') //get password from visitor

{

ch=takekey();

ch1=ch;

if(ch!='=')

{

lcd_data(ch);

key=((key*10)+(ch1-0x30));

}

else

break;

}

lcd_cmd(0x01);

lcd_cmd(0xce);

key1=key;

while(key)

{

lcd_data((key%10)+0x30);

lcd_cmd(0x10);

lcd_cmd(0x10);

key=key/10;

}

ch=takekey();

if(key1!=5555) //compare the entered password

{

lcd_cmd(0x01);

lcd_cmd(0xc1);

for(i=0;i<15; i++)

lcd_data(w[i]);

PORTD=0X0f;

ch=takekey();

}

else

{

PORTD=0XF0;

ch=takekey();

PORTD=0;

}

lcd_cmd(0x01);

}

}