4 Digit Security lock with 4x4 Matrix Keypad and I2C LCD display.

//current password is 1234,press# key to change new password and enter new password 2 times to confirm.

#include <Keypad.h>

#include<EEPROM.h>

#include <Wire.h> 

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

char password[4];// current password is 1234

char initial_password[4],new_password[4];// press"#" symbol to change current password  

int vcc=11;

int i=0;

int relay_pin = 11;

char key_pressed=0;

const byte rows = 4; 

const byte columns = 4; 

char hexaKeys[rows][columns] = {

{'1','2','3','A'},

{'4','5','6','B'},

{'7','8','9','C'},

{'*','0','#','D'}

};

byte row_pins[rows]={2,3,4,5};

byte column_pins[columns]={6,7,8,9};

Keypad keypad_key=Keypad( makeKeymap(hexaKeys),row_pins,column_pins,rows,columns);

void setup(){

lcd.begin();

lcd.backlight();

pinMode(relay_pin, OUTPUT);

pinMode(vcc, OUTPUT);

lcd.print("ANOKHAUTOMATION ");

lcd.setCursor(0,1);

lcd.print("Secutity Lock ");

delay(3000);

lcd.clear();

lcd.print("Enter Password");

lcd.setCursor(0,1);

initialpassword();

}

void loop(){

digitalWrite(relay_pin,LOW);

key_pressed = keypad_key.getKey();

if(key_pressed=='#')

change();

if (key_pressed)

{

password[i++]=key_pressed;

lcd.print("*");//Hide the password with * symbol

}

if(i==4)

{

delay(200);

for(int j=0;j<4;j++)

initial_password[j]=EEPROM.read(j);

if(!(strncmp(password, initial_password,4))){

lcd.clear();

lcd.print("Pass Accepted");

digitalWrite(relay_pin,HIGH);

delay(2000);

lcd.setCursor(0,0);

lcd.print("Pres >START< to");

lcd.setCursor(0,1);

lcd.print("change the pass");

delay(3000);

lcd.clear();

lcd.print("Enter Password:");

lcd.setCursor(0,1);

i=0;

}

else{

digitalWrite(relay_pin,LOW);

lcd.clear();

lcd.print("Wrong Password");

lcd.setCursor(0,0);

lcd.print("Pres >#< to");

lcd.setCursor(0,1);

lcd.print("change the pass");

delay(2000);

lcd.clear();

lcd.print("Enter Password");

lcd.setCursor(0,1);

i=0;

}}}

void change(){

  int j=0;

lcd.clear();

lcd.print("Current Password");

lcd.setCursor(0,1);

while(j<4){

char key=keypad_key.getKey();

if(key)

{

new_password[j++]=key;

lcd.print(key);

}

key=0;}

delay(500);

if((strncmp(new_password, initial_password, 4))){

lcd.clear();

lcd.print("Wrong Password");

lcd.setCursor(0,1);

lcd.print("Try Again");

delay(1000);}

else{

j=0;

lcd.clear();

lcd.print("New Password:");

lcd.setCursor(0,1);

while(j<4){

char key=keypad_key.getKey();

if(key)

{

initial_password[j]=key;

lcd.print(key);

EEPROM.write(j,key);

j++;}}

lcd.print("Pass Changed");

delay(1000);}

 

lcd.clear();

lcd.print("Enter Password");

lcd.setCursor(0,1);

key_pressed=0;

}

void initialpassword(){

int j;

for(j=0;j<4;j++)

EEPROM.write(j,j+49);

for(j=0;j<4;j++)

initial_password[j]=EEPROM.read(j);}