Hello friends,
I am a begginer in arduino .I am doing a project for monitoring a machine.The concept is,first we have to set any count through a matrix keypad,for example 50.That count can be changed only by entering password,by authorised person.When the count is reached,a buzzer should ring.Please guide me 
i have designed the following code.Please guide me in adding necessary codes.
Thank you,
Karthick.N
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My code for setting password.
In this code,when A is pressed,It should show “Set tool life”,and we have to enter the count.Then we use another count with one minute delay .when both the count are equal,buzzer should ring.
code:
#define Password_Lenght 7
#include <Keypad.h>
#include<LiquidCrystal.h>
LiquidCrystal lcd(A0,A1,A2,A3,A4,A5);
int row={9,8,7,6};
int col= {5,4,3,2};
int i,j,lcd_count,count=1,key_id=0,flag,entry=0;// See About the Program
int col_scan;// Variable to identify a key press
char temp_press; // Variable to hold value of key press
char check[6],pass[6]; // See About the Program
int countnew=0;
void setup()
{
lcd.begin(16,2);
for(i=0;i<=3;i++)
{
pinMode(row*,OUTPUT);*
pinMode(col*,INPUT);*
digitalWrite(col*,HIGH);*
}
lcd.print(“SET 5 Digit PASS”);
}
/* Main Program Begins */
void loop()
{
while(entry<=4)// Password Setting Loop begins
{
SetPassword();
}
// Password Setting Loop Ends
key_id=0;
keyscan(); // Scan for a Key Press
/* Actions on Key Press begins */
if(key_id==1) // Condition to Check Key is Pressed
{
check[count]=temp_press;
count++;
/* Condition to Unlock Begins*/
if(temp_press==‘A’)
{
* checkPassword();*
if(flag==0)
{
lcd.setCursor(0,0);
lcd.print(“SET-Toollife”);
}else{
lcd.setCursor(0,0);
lcd.print(“WRONG PASSWORD”);
delay(200);
lcd.clear();
lcd.print(“LOCKED”);
}
count=1; // Resetting the counter variable
}
/* Condition to Unlock Ends*/
/* Condition to Change Password Begins */
else if(temp_press==‘C’)
{
checkPassword();
if(flag==0)
{
lcd.setCursor(0,0);
lcd.print(“ENTER NEW PASS”);
key_id=0;
entry=0;
}else{
lcd.setCursor(0,0);
lcd.print(“WRONG PASSWORD”);
}
count=1; // Resetting the counter variable
}
/* Condition to Change Password Ends */
/* Condition to LOCK Begins*/
else if(temp_press==‘B’)
{
lcd.setCursor(0,0);
lcd.print(“LOCKED”);
count=1; // Resetting the counter variable
}
/* Condition to LOCK Ends*/
}
/* Actions on Key Press Ends*/
}
/* Main Program Ends */
void SetPassword() // Subroutine to SET User Defined Password
{
keyscan();
if(key_id==1)
{
if(temp_press==‘A’||temp_press==‘C’||temp_press==‘B’) // Condition to Check for an Invalid Keypress
{
lcd.setCursor(0,0);
lcd.print(“INVALID KEYS”);
entry=0;
}
else
{
* pass[entry]=temp_press;
_}
}
key_id=0;
if(entry==5)
{
lcd.clear();
lcd.setCursor(0,0);
lcd.print(“PASSWORD SET & LOCKED”);
}} // Subroutine to SET Password ENDS*
char keyscan()// Subroutine to Scan Keypad for a Keypress
{
for(i=0; i<=3; i++)
{
digitalWrite(row[0],HIGH);
digitalWrite(row[1],HIGH);
digitalWrite(row[2],HIGH);
digitalWrite(row[3],HIGH);
digitalWrite(row*,LOW);*
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==LOW)
{
* key_id=1;*
* entry++;
temp_press=keypress(i,j);
lcd.setCursor(lcd_count++,1);
lcd.print(temp_press);
if(temp_press==‘A’||temp_press==‘C’||temp_press==‘B’)
{
lcd_count=0;
lcd.clear();
}
delay(300);
break;
}}
}}// Subroutine to Scan Keypress Ends*
char keypress(int i, int j) // Subroutine to Identify the value of Key pressed
{
if(i==0&&j==0)
{
return(‘1’);
}
if(i==0&&j==1)
{
return(‘2’);
}
if(i==0&&j==2)
{
return(‘3’);
}
if(i==0&&j==3)
{
return(‘A’);
}
if(i==1&&j==0)
{
return(‘4’);
}
if(i==1&&j==1)
{
return(‘5’);
}
if(i==1&&j==2)
{
return(‘6’);
}
if(i==1&&j==3)
{
return(‘B’);
}
if(i==2&&j==0)
{
return(‘7’);
}
if(i==2&&j==1)
{
return(‘8’);
}
if(i==2&&j==2)
{
return(‘9’);
}
if(i==2&&j==3)
{
return(‘C’);
}
if(i==3&&j==0)
{
return(’*’);
}
if(i==3&&j==1)
{
return(‘0’);
}
if(i==3&&j==2)
{
return(’#’);
}
if(i==3&&j==3)
{
return(‘D’);
}
} // Subroutine to identify Keypress Ends
void checkPassword() // Subroutine to Check User Input Data with SET Password
{
flag=0;
for(i=1;i<=5&&flag==0;i++)
{
if(check==pass*)
{
flag=0;
}
else
{flag=1;
}}} // Subroutine to check password ends*_
