Hello Roy,

                 Get 1 AT89c51/AT89s52 which costs you around Rs.50-60.. i think you read the book of 8051 by Mazidi.. you will get to know how to Program and how to build circuit.

Get 40 pin base, 11.0592Mhz crystal, 33pf, 8.2k resistor,10microcfarad capacitor and a reset switch ,2×16 LCD, 4×3 keypad, pull up resistors general PCb, soldering gun etc………

Get 1 8051 Programmer to send the hex file into microcontroller

Download Keil M vision 3

then write the Program in Keil in that only you will get the option to convert C file into hex file…

While Purchasing Programmer they will Provide software .Run on Your PC.

Open that Choose the Hex file to transfer to microcntroller

i had made my own codings for

key pad lock

i think it is helpfullwysiwyg_imageupload:3745:

codings for the above circuit

#include <reg51.H>          //……………….headder file
#include <stdio.h>          //……………….headder file
#include <string.h>     //……………….headder file

/*………………PIN CONNECTIONS…………………………………………………………….*/

#define LCD_PORT P2        //……………….lcd data port to be connected
#define    port0 P0        //……………….Port for keypad connection
#define REL_PORT P1        //……………….relay connection port
sbit    LED2=P3^3;        //……………….LCD PIN Connection
sbit    EN=P3^7;        //……………….enable pin for LCD
sbit    RW=P3^6;        //……………….write pin for LCD         
sbit    RS=P3^5;        //……………….register select pin of LCD

/*………………..Declarations ……………………………………………*/

//………………..DELAYS………………………//

void Delay_in_ms(unsigned char);    //……………..milli second delay is to be specifide
void Delay_in_10ms(unsigned char);    //……………..10 * number of milli sec
void Delay_in_1s(unsigned char);    //……………..number of sec

//………………….LCD………………………//

void lcd_init        (void);                    //………routine to initialise LCD
void write_in        (unsigned char );        //………writes data in to LCD as instruction
void write            (unsigned char );        //………writes one byte into LCD
void printLcd        (unsigned char *);        //………prints a line on LCD
void printLcd2        (unsigned char *);        //………prints a line on LCD
void clear_display    (void);                    //………clears LCD screen
void set_add        (unsigned char );        //………sets the display position
void write_data        (unsigned char );        //………writes one byte into LCD as data

//………………..relay………………………//

void RELAY_GO(unsigned char ,unsigned char );    //…..selection of relay through keybord
void relay_set(unsigned char);                    //…..selected relay ON or OFF            
#define RON  1         //……………………………relay pin on state
#define ROFF 0         //……………………………relay pin off state
sbit RELAY1 = P1^0;    //……………………………relay one
sbit RELAY2 = P1^1;    //……………………………relay two
sbit RELAY3 = P1^2;    //……………………………relay three
sbit RELAY4 = P1^3;    //……………………………relay four
sbit RELAY5 = P1^4;    //……………………………relay five
sbit RELAY6 = P1^5;    //……………………………relay six
sbit RELAY7 = P1^6;    //……………………………relay seven
sbit RELAY8 = P1^7;    //……………………………relay eight

/* ………………password functions…………………*/

char  key0 = ‘*’;            //……………………..MASK key press
unsigned char key1;            //……………………..1 key press
unsigned char key2;            //……………………..2 key press
unsigned char key3;            //……………………..3 key press
unsigned char key4;            //……………………..4 key press
unsigned char key5;            //……………………..5 key press
unsigned char key6;            //……………………..6 key press

void relese_go(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char);
void lock_go(unsigned char , unsigned char , unsigned char , unsigned char , unsigned char , unsigned char );

/*…………………….4X4 keybord……………………*/

// key select functions

void select(void);                //……………………..selection of relay
void locker();                    //……………………..lockre rootine
void menu_1(void);                //……………………..function choose
void menu_2(void);                //……………………..function choose
void stop(void);                //……………………..system halt
void sleep(void);                //……………………..system standby
unsigned char keyS;                //……………………..selected key
unsigned char keypad(void);        //……………………..key input
void call_for_column(void);        //……………………..key routien work
unsigned char getport0,col,row;    //…………………..key routien work
unsigned char keypad_value;        //……………………..value of key
unsigned char key[4][4] = { ‘1’,’2′,’3′,’R’,
                            ‘4’,’5′,’6′,’P’,
                            ‘7’,’8′,’9′,’L’,
                            ‘*’,’0′,’#’,’S’};

//………………progam starts………………………………….//
void main()
{
    REL_PORT=0x00;                        //………initialising relay port
    lcd_init();                            //………initialising lcd port
    lock= ROFF;    
    clear_display();                    //………clear th display
        printLcd(”  Dexter8051  “);        //……..FOR PRINTING IN FIRST LINE
        printLcd2(” WELCOMES YOU    “);    //……..FOR PRINTING IN SECAND LINe
        Delay_in_1s(2);*/

        locker();
    }    
}

//……………..menu 1 select………………//

void menu_1(void )
    {
    clear_display();
    printLcd (“RELAY :press R “);
    keyS= keypad();
    if(keyS==’R’)
                {
                select();
                }
    else
        {
        clear_display();
        printLcd(“WRONG INPUT”);
        Delay_in_1s(1);
        menu_1();
        }
    }

//…………on off select function………….//

void select(void)
{
    clear_display();
    printLcd(“Enter relay no:”);
    key1=keypad();
    write_data(key1);
    Delay_in_10ms(2);
    set_add(0xc0);
    printLcd(“PRESS # ON * OFF”);
    Delay_in_1s(1);
    key2=keypad();
    Delay_in_10ms(2);
    clear_display();
    RELAY_GO(key1,key2);
    Delay_in_1s(1);
    menu_1();
}

//…………………..relay to be on off select rooine…………//

void RELAY_GO(unsigned char a,unsigned char b)
{
    {
    if(a==’1’& b==’#’)
                {
                relay_set(1);// RELAY 1 on //calling relay_set function
                }
else if(a==’1’& b==’*’)
                {
                relay_set(2);// RELAY 1 off //calling relay_set function
                }
else if(a==’2’& b==’#’)
                {
                relay_set(3);// RELAY 2 on //calling relay_set function
                }
else if(a==’2’& b==’*’)
                {
                relay_set(4);// RELAY 2 off //calling relay_set function
                }
else if(a==’3’& b==’#’)
                {
                relay_set(5);// RELAY 3 on //calling relay_set function
                }
else if(a==’3’& b==’*’)
                {
                relay_set(6);// RELAY 3 off //calling relay_set function
                }
else if(a==’4’& b==’#’)
                {
                relay_set(7);// RELAY 4 on //calling relay_set function
                }
else if(a==’4’& b==’*’)
                {
                relay_set(;// RELAY 4 off //calling relay_set function
                }
else if(a==’5’& b==’#’)
                {
                relay_set(9);// RELAY 5 on //calling relay_set function
                }
else if(a==’5’&b==’*’)
                {
                relay_set(10);// RELAY 5 off //calling relay_set function
                }
else if(a==’6’&b==’#’)
                {
                relay_set(11);// RELAY 6 on //calling relay_set function
                }
else if(a==’6’& b==’*’)
                {
                relay_set(12);// RELAY 6 off //calling relay_set function
                }
else if(a==’7’& b==’#’)
                {
                relay_set(13);// RELAY 7 on //calling relay_set function
                }
else if(a==’7’& b==’*’)
                {
                relay_set(14);// RELAY 7 off //calling relay_set function
                }
else if(a==’8’& b==’#’)
                {
                relay_set(15);// RELAY 8 on //calling relay_set function
                }
else if(a==’8′ & b==’*’)
                {
                relay_set(16);// RELAY 8 off //calling relay_set function
                }
    else
            {
              clear_display();
            printLcd(“WRONG INPUT KEY”);
            }
        }
}

//…………………LCD Routines…………………..//

//routine to initialise the lcd
void lcd_init(void)
{        
    write_in(0x38);          //to make lcd
    Delay_in_ms(1);
    write_in(0x0f);          //to make lcd to select 5×7 matrix display
    Delay_in_ms(1);
     write_in(0x01);          //to make lcd to clear the display
    Delay_in_ms(1);
    write_in(0x80);          //to make lcd cursor to bigining of first line
    Delay_in_ms(1);
}
//routine to write an instruction to LCD
void write_in(unsigned char ch)
{
    RS=0;                //rs =0 for instr
    RW=0;            
    write(ch);            //routine to transfer 8 bits to LCD
}
//routine to transfer 8 bits to LCD module
void write(unsigned char ch)
{
    LCD_PORT = ch;        //preserves the old value of port
    EN = 1;                //enable pin high
    Delay_in_ms(1);
    EN = 0;                //enable = 0
}
//clears the entire display area of LCD
void clear_display(void)
{
    write_in(0x01);            //clears the lcd display
    write_in(0x80);            //write code to blink at first line first coloum
}
//printing rootin
//routine to display the value in the accumulator in LCD
//routine to display a string on first line
//this routine will display a string stored at address pointed by dptr
void printLcd(unsigned char *str)
{
    unsigned char len,i;
    len = strlen(str);
    set_add(0x80);                //sets display position in first line
    for(i=0;i<len;i++)
    {
    write_data(*str);        //displays the character on LCD
    str++;
    }
}
void printLcd2(unsigned char *str)
{
    unsigned char len,i;
    len = strlen(str);
    set_add(0xc0);        //sets display position in second  line
    
    for(i=0;i<len;i++)
        {
            write_data(*str);    //displays the character on LCD
            str++;
        }
}
//routine to set the display position
void set_add(unsigned char ch)
{
    write_in(ch);        //writes it as instruction
}
//routine to write a data to LCD
void write_data(unsigned char ch)
{
    RS = 1;
    RW=0;            
    write(ch);            //……….transfers 8 bits to lcd module    
}
//ms delay in milli secand
void Delay_in_1s(unsigned char ms)//……………..number of secands
{
    int t;
    t=ms;
    {
    unsigned int i;
    for(i=0;i<t;i++)
    {
    Delay_in_10ms(10);
    }
    }
}    
void Delay_in_10ms(unsigned char ms)//……………..milli sec * 10
{
    int t;
    t=ms;
    {
    unsigned int i;
    for(i=0;i<t;i++)
    {
    Delay_in_ms(100);
    }
    }
}    
void Delay_in_ms(unsigned char ms)//……………….milli sec
{
    int t;
    t= ms;
    {
    unsigned int i,j;
    for(i=0;i<t;i++)
    for(j=0;j<120;j++);
    }
}
//…………..key board processes……………..//

unsigned char keypad()
{
    do
    {
        do
        {
        port0 = 0x0f;
        getport0 = port0;
        getport0 = getport0 & 0x0f;
        }while(getport0 != 0x0f);
    
    getport0 = port0;
    getport0 = getport0 & 0x0f;
    }while(getport0 !=0x0f);
    
    while(1)
    {
            port0 = 0xef;
            getport0 = port0;
            getport0 = getport0 & 0x0f;
            if(getport0 != 0x0f)
            {
                row = 0;
                call_for_column();

                break;
            }
            port0 = 0xdf;
            getport0 = port0;
            getport0 = getport0 & 0x0f;
            if(getport0 != 0x0f)
            {
                row = 1;
                call_for_column();
                break;
            }
           
            port0 = 0xbf;
            getport0 = port0;
            getport0 = getport0 & 0x0f;
            if(getport0 != 0x0f)
            {
                row = 2;
                call_for_column();
                break;
            }
           
            port0 = 0x7f;
            getport0 = port0;
            getport0 = getport0 & 0x0f;
            if(getport0 != 0x0f)
            {
                row = 3;
                call_for_column();
                break;
            }
    }
keypad_value = key[row][col];
return keypad_value;
}
void call_for_column()
{
    while(1)
    {
        if(getport0 == 0x07)
        {
            col = 0;
           
            Delay_in_10ms(3);
           
            break;
        }
        else if(getport0 == 0x0b)
        {
            col = 1;
           
            Delay_in_10ms(3);
           
            break;
        }
        else if(getport0 == 0x0d)
        {
            col = 2;
           
            Delay_in_10ms(3);
           
            break;
        }
        else if(getport0 == 0x0e)
        {
            col = 3;
           
            Delay_in_10ms(3);
           
            break;
        }
    }
}

//……….relay switching processes……………..//

void relay_set(unsigned char relay)
{
    int x;
    x= relay;
     switch (x)
    {
    case 1:            //………………..RELAY 1 OFF
   RELAY1= RON;
       printLcd(“RELAY 1 ON “);
    break;
    case 2:            //………………..RELAY 1 0N
   RELAY1= ROFF;
    printLcd(“RELAY 1 OFF”);
    break;
    case 3:            //………………..RELAY 2 OFF
   RELAY2= RON;
   printLcd(“RELAY 2 ON “);
    break;
    case 4:            //………………..RELAY 2 0N
   RELAY2= ROFF;
   printLcd(“RELAY 2 OFF”);
    break;
    case 5:            //…………………RELAY 3 OFF
   RELAY3= RON;
   printLcd(“RELAY 3 ON “);
    break;
    case 6:            //………………..RELAY 3 0N
   RELAY3= ROFF;
   printLcd(“RELAY 3 OFF”);
    break;
    case 7:            //………………..RELAY 4 OFF
   RELAY4= RON;
   printLcd(“RELAY 4 ON “);
    break;
    case 8:            //………………..RELAY 4 0N
   RELAY4= ROFF;
   printLcd(“RELAY 4 OFF”);
    break;
    case 9:            //………………..RELAY 5 OFF
   RELAY5= RON;
   printLcd(“RELAY 5 ON “);
    break;
    case 10:            //……………….RELAY 5 0N
   RELAY5= ROFF;
   printLcd(“RELAY 5 OFF”);
    break;
    case 11:            //……………….RELAY 6 OFF
   RELAY6= RON;
   printLcd(“RELAY 6 ON “);
    break;
    case 12:            //………………..RELAY 6 0N
   RELAY6= ROFF;
   printLcd(“RELAY 6 OFF”);
    break;
    case 13:            //………………..RELAY 7 OFF
   RELAY7= RON;
   printLcd(“RELAY 7 ON “);
    break;
    case 14:            //………………..RELAY 7 0N
   RELAY7= ROFF;
   printLcd(“RELAY 7 OFF”);
    break;
    case 15:            //………………..RELAY 8 0FF
   RELAY8= RON;
   printLcd(“RELAY 8 ON “);
    break;
    case 16:            //………………..RELAY 8 0N
   RELAY8= ROFF;
   printLcd(“RELAY 8 OFF”);
    break;
    }
}

//…………..locker password code…………….//

void locker(void)
{    
    clear_display();
    printLcd(“ENTER PASSWORD”);
    set_add(0xc0);
    key1=keypad();
    write_data(key0);
    key2=keypad();
    write_data(key0);
    key3=keypad();
    write_data(key0);
    key4=keypad();
    write_data(key0);
    key5=keypad();
    write_data(key0);
    key6=keypad();
    write_data(key0);
    lock_go(key1,key2,key3,key4,key5,key6);
}
//……………………..lock code ………………………//

void lock_go(unsigned char a, unsigned char b, unsigned char c, unsigned char d, unsigned char e, unsigned char f)
{
    if(a==’1′ & b==’2′ & c==’3′ & d==’4′ & e==’5′ & f==’6′)
            {
            clear_display();
            printLcd(“CORRECT PASSWORD”);
            printLcd2(“LOCK IS OPEN”);
            Delay_in_1s(1);
            menu_1();
            }
    else
        {

        locker();
        }
}