rfid report

Project 2011 RFID Based Attendance System

ACKNOWLEDGEMENT

We should like to express our heartfelt gratitude to Mrs. C.G. Anitha, Principal of our polytechnic for providing the best facility and atmosphere for this Project work.

We greatly thankful to Mrs. Suhara .K.M, Head of Department of Electronics for all necessary help extended by her in the fulfillment of this Project.

We acknowledge our Project guide Mr.Devarajan.M.K, Mr. Sureshkumar.K.B, Mrs.sussamma Mathew, Mrs. Padmaja Detha, Lucturers in Electronics Engineering for the guidance and help they have always given us.

Finally we thank all our colleagues for their heartfelt co-operation and tremendous support they have given to us during the collection of materials and also during our Project.

Department of Electronics 1 Govt.Polytechnic College,Nattakom


CONTENTS

1.INTRODUCTION

2.BLOCK DIAGRAM DESCRIPTION

3.EXPLANATION

4.CIRCUIT DIAGRAM

5.FLOW CHART

6.PROGRAM

7.PCB LAYOUT

8.PCB FABRICTION

9. MERITS AND DEMERITS

10.FUTURE ENHANCEMENT

11.CONCLUSION

12REFERENCE



CHAPTER 1

INTRODUCTION

Traditionally the attendance at an establishment is usually done in a

book register. It is time consuming. It is very difficult to verify the

attendance over long periods. This method is very time consuming and

very difficult to verify the attendance over a week or above. Keeping

attendance registers is space consuming. Here chances of doing

malpractice in marking attendance are high.

RFID based attendance system uses RFID tags for each person. A

person marks the attendance by swiping the tag near RFID reader module.

The attendance is temporarily saved in the EEPROM. At any time the

circuit can be connected to a computer and the attendance is moved from

EEPROM to a text file in computer. It has following advantages. (1)

Simplicity and reliability, (2) Saving attendance in a computer allows easy

verification and longer record keeping.

It works on radio frequency transmitters and receivers. Each person

is given a RF ID card which is having a unique code. When it is swiped on

a RF ID card reader, it reads the code and is stored. The attendance is

temporarily saved in the EEPROM. At any time the circuit can be

connected to a computer and the attendance is moved from EEPROM to a

text file in computer. The advantage of this system is simplicity and

reliability. Saving attendance in a computer allows easy verification and

longer record keeping.



CHAPTER 2

BLOCK DIAGRAM AND EXPLANATION

2.1 Block Diagram

Figure 2.1 Basic block diagram

2.2 EXPLANATION

RFID READER

The DT125R series RFID Proximity OEM Reader Module has a built-

in antenna in minimized form factor. It is designed to work on the industry

standard carrier frequency of 125 kHz. This LF reader module with an

internal or an external antenna facilitates communication with Read-Only



transponders type UNIQUE or TK5530 via the air interface. The tag data

is sent to the host systems via the wired communication interface with a

protocol selected from the module pinout. The LF DT125R module is best

suited for applications in Access Control, Time and Attendance, Asset

Management, Handheld Readers, Immobilizers, and other RFID enabled

applications.The AUTOMATIC DATA COLLECTION Technology used

in th RFID reader.

Features

Selectable UART or Wigand26.

Plug-and-Play, needs +5V to become a reader.

No repeat reads.

LED/Beeper indicates tag reading operation.

Excellent read performance without an external circuit.

Compact size and cost-effective very efficient module for portable

readers.

Data Transmission is in ASCII Standard. Data read from the tag is

Manchester encoded. The Manchester encoded data is decoded to ASCII

standard. Decoded data is sent to the UART serial interface for wired

communication with the host systems. ASCII data format is shown below:



2.2.2 Power supply

Block diagram of Power Supply

Regulated

output

Figuer 2.2 Block diagram of power supply

Almost all electronic devices used in electronic circuits need a dc

source of power supply to operate .The source of dc power is used to

establish the dc operating points for the passive and active electronic

devices incorporated in the system. The combination of a transformer, a

rectifier, and a filter constitutes an ordinary dc supply, also called an

unregulated power supply. For many applications in electronics

unregulated power supply is not good because of the following reasons.

Poor regulation.

Variations in the ac supply main.

Variations in temperature.

(1)Transformer

Transformers are devices which are designed to transfer electrical

energy from one electrical circuit to another. They do so utilizing the


TRANSFORMER

TRANSFORMER

BRIDGE

RECTIFIER

FILTER

VOLTAGE REGULATOR


principle of electromagnetic induction. In addition to performing such

energy transfer they are also capable of delivering a different value of ac

current or voltage at their output terminals than the value applied to other

input terminal. Transformer can provide isolation. In this circuit step down

transformer is used.

(2) Bridge rectifier

In the bridge circuit 4 diodes are connected I the form of a

Wheatstone bridge. When the upper end of the transformer secondary

winding is positive, say during first half cycle of the input supply, diodes

D1 and D3 are forward biased and current flows through the arm AB,

enters the load at positive terminal leaves the load at negative terminal.

During the negative half cycle, the diodes D2 and D4 are forward biased so

the current is not allowed to flow in arms AD and BC. In both cases the

direction of flow of current through load resistance is same.

(3) Voltage Regulator (7805)

Fixed three-terminal linear regulators are commonly available to

generate fixed voltage of plus 3V, and plus or minus 5V, 9V, 12V or 15V

when the load is less than about 7 amperes. The “78” series (7805, 7812,

etc) regulate positive voltages. Often, the last two digits of the device

numbers are the output voltages, e.g. a 7805 is a +5V regulator. These

regulators eliminate the distribution problems associated with single point

regulation.



Figure 2.3 Power supply circuit

2.2.3 MICROCONTROLLER AT89C52

It has 8K Bytes of In-System Programmable (ISP) Flash Memory. It

has an endurance of 1000 write and erase cycles. It has a 256 x 8-bit

Internal RAM. It is having 32 programmable I/O lines. There are three 16-

bit Timers or Counters. There are eight interrupt sources. It consists of a

full duplex UART serial channel. The 8KB internal flash type ROM is

used for storing user program. It has low-power Idle and Power-down

modes. The AT89C52 is a low-power, high-performance CMOS 8-bit

microcomputer with 8K bytes of Flash programmable and erasable read

only memory (PEROM). The device is manufactured using Atmel’s high-

density nonvolatile memory technology and is compatible with the

industry-standard 80C51 and 80C52 instruction set and pinout. The on-

chip Flash allows the program memory to be reprogrammed in-system or

by a conventional nonvolatile memory programmer. By combining a

versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C52

is a powerful microcomputer which provides a highly-flexible and cost-

effective solution to many embedded control applications. The AT89C52

provides the following standard features: 8K bytes of Flash, 256 bytes of

RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level

interrupt architecture, a full-duplex serial port, on-chip oscillator, and

clock circuitry. In addition, the AT89C52 is designed with static logic for



operation down to zero frequency and supports two software selectable

power saving modes. The Idle Mode stops the CPU while allowing the

RAM, timer/counters, serial port, and interrupt system to continue

functioning.

ARCHITECTURE OF AT89C52

Figure 2.4 89C52 Architecture



The Accumulator

The Accumulator, as its name suggests, is used as a general register

to accumulate the results of a large number of instructions. It can hold an

8-bit (1-byte) value and is the most versatile register the 8052 has due to

the sheer number of instructions that make use of the accumulator.

The "R" registers

The "R" registers are a set of eight registers that are named R0, R1,

etc. up to and including R7. The "R" registers as very important auxiliary,

or "helper", registers. The Accumulator alone would not be very useful if it

were not for these "R" registers. The "R" registers are also used to

temporarily store values.

The "B" Register

The "B" register is very similar to the Accumulator in the sense that

it may hold an 8-bit (1-byte) value. The "B" register is only used by two

8052 instructions: MUL AB and DIV AB. Thus, if you want to quickly

and easily multiply or divide A by another number, you may store the

other number in "B" and make use of these two instructions. Aside from

the MUL and DIV instructions, the "B" register is often used as yet another

temporary storage register much like a ninth "R" register.

Dual Data Pointer Registers

To facilitate accessing both internal and external data memory, two

banks of 16-bit Data Pointer Registers are provided: DP0 at SFR address

locations 82H-83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1

selects DP0 and DPS = 1 selects DP1. The user should always initialize the



DPS bit to the appropriate value before accessing the respective Data

Pointer Register.

The Program Counter (PC)

The Program Counter (PC) is a 2-byte address which tells the 8052

where the next instruction to execute is found in memory. When the 8052

is initialized PC always starts at 0000h and is incremented each time an

instruction is executed. It is also interesting to note that while you may

change the value of PC (by executing a jump instruction, etc.) there is no

way to read the value of PC.

The Stack Pointer (SP)

The Stack Pointer, like all registers except DPTR and PC, may hold

an 8-bit value. The Stack Pointer is used to indicate where the next value

to be removed from the stack should be taken from. This order of operation

is important. When the 8052 is initialized SP will be initialized to 07h. If

you immediately push a value onto the stack, the value will be stored in

Internal RAM address 08h. SP is modified directly by the 8052 by six

instructions: PUSH, POP, ACALL, LCALL, RET, and RETI.

SFRs

A map of the on-chip memory area is called the Special Function

Register (SFR) space. Note that not all of the addresses are occupied, and

unoccupied addresses may not be implemented on the chip. Read accesses

to these addresses will in general return random data, and write accesses

will have an indeterminate effect. User software should not write 1s to

these unlisted locations, since they may be used in future products to



invoke new features. In that case, the reset or inactive values of the new

bits will always be 0.

PSW Register (Program Status Word)

This is one of the most important SFRs. The Program Status

Word (PSW) contains several status bits that reflect the current state of the

CPU. This register contains: Carry bit, Auxiliary Carry, two register bank

select bits, Overflow flag, parity bit, and user-definable status flag. The

ALU automatically changes some of register’s bits, which is usually used

in regulation of the program performing.

Program Memory

Code memory is the memory that holds the actual 8052 program that

is to be run. In 89S52 the internal code memory is a Flash memory.

Internal code memory is limited to 8K. Code may also be stored

completely off-chip in an external ROM or, more commonly, an external

EPROM. Flash RAM is also another popular method of storing a program.

The microcontroller handle external memory depends on the pin EA

logic state:

EA=0. In this case, internal program memory is completely ignored, only a

program stored in external memory is to be executed.

EA=1 In this case, a program from built in FLASH is to be executed first

(to the last location). Afterwards, the execution is continued by reading

additional memory.

In both cases, P0 and P2 are not available to the user because

they are used for data and address transmission. Besides, the pins ALE and

PSEN are used too.

Data Memory (RAM)



The AT89S52 implements 256 bytes of on-chip RAM. The upper

128 bytes occupy a parallel address space to the Special Function

Registers. This means that the upper 128 bytes have the same addresses as

the SFR space but are physically separate from SFR space. When an

instruction accesses an internal location above address 7FH, the address

mode used in the instruction specifies whether the CPU accesses the upper

128 bytes of RAM or the SFR space. Instructions which use direct

addressing access the SFR space. Instructions that use indirect addressing

access the upper 128 bytes of RAM. Note that stack operations are

examples of indirect addressing, so the upper 128 bytes of data RAM are

available as stack space.

Counters and Timers

The 8052 microcontrollers have 3 timers/counters called T0, T1 and

T2. As their names tell, their main purpose is to measure time and count

external events. Besides, they can be used for generating clock pulses used

in serial communication, i.e. Baud Rate.

UART (Universal Asynchronous Receiver and Transmitter)

The UART in the AT89S52 operates the same way as the UART in

the AT89C51 and AT89C52. Also known as a serial port. It is a duplex

port, which means that it can transmit and receive data simultaneously.

P0, P1, P2, P3 - Input/output ports

4 ports within a total of 32 input-output lines are available to the

user for connection to peripheral environment



T2CON – Timer/Counter 2 Control Register

TF2- Timer 2 overflow flag set by a Timer 2 overflow and must be cleared

by software. TF2 will not be set when either RCLK = 1 or TCLK = 1.

EXF2- Timer 2 external flag set when either a capture or reload is caused

by a negative transition on T2EX and EXEN2 = 1. When Timer 2 interrupt

is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt

routine. EXF2 must be cleared by software. EXF2 does not cause an

interrupt in up/down counter mode (DCEN = 1).

RCLK- Receive clock enable. When set, causes the serial port to use

Timer 2 overflow pulses for its receive clock in serial port modes 1 and 3.

RCLK = 0 causes Timer 1 overflow to be used for the receive clock.

TCLK- Transmit clock enable. When set, causes the serial port to use

Timer 2 overflow pulses for its transmit clock in serial port modes 1 and 3.

TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.

EXEN2- Timer 2 external enable. When set, allows a capture or reload to

occur as a result of a negative transition on T2EX if Timer 2 is not being

used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at

T2EX.

TR2- Start/Stop control for Timer 2. TR2 = 1 starts the timer.

C/T2- Timer or counter select for Timer 2. C/T2 = 0 for timer function.

C/T2 = 1 for external event counter (falling edge triggered).

CP/RL2- Capture/Reload select. CP/RL2 = 1 causes captures to occur on

negative transitions at T2EX if EXEN2 = 1. CP/RL2 = 0, causes automatic



reloads to occur when Timer 2 overflows or negative transitions occur at

T2EX when EXEN2 = 1.

IE (Interrupt Enable Register)

EA - Disables all interrupts. If EA = 0, no interrupt is acknowledged. If

EA = 1, each interrupt source is individually enabled or disabled by setting

or clearing its enable bit.

ET2 - Timer 2 interrupt enable bit.

ES - Serial Port interrupt enable bit.

ET1 - Timer 1 interrupt enable bit.

EX1 - External interrupt 1 enable bit.

ET0 -Timer 0 interrupt enable bit.

EX0 - External interrupt 0 enable bit.

WATCH DOG TIMER

The WDT is intended as a recovery method in situations where the

CPU may be subjected to software upsets. The WDT consists of a 14-bit

counter and the Watchdog Timer Reset (WDTRST) SFR. The WDT is

defaulted to disable from exiting reset. To enable the WDT, a user must

write 01EH and 0E1H in sequence to the WDTRST register (SFR location

0A6H). When the WDT is enabled, it will increment every machine cycle

while the oscillator is running. The WDT timeout period is dependent on

the external clock frequency. There is no way to disable the WDT except

through reset (either hardware reset or WDT overflow reset). When WDT

overflows, it will drive an output RESET HIGH pulse at the RST pin.



2.2.4 REAL TIME CLOCK (DS12887)

It is totally nonvolatile with over 10 years of operation in the

absence of power. It has a self-contained subsystem that includes lithium,

quartz, and support circuitry. It counts seconds, minutes, hours, day of the

week, date, month, and year with leap year compensation valid up to 2100.

It also has binary or BCD representation of time, calendar, and alarm. It

has 12 or 24 hour clock with AM and PM in 12 hour mode. Daylight

savings time option is also present in it. It is interfaced with software as

128 RAM locations, ie.15 bytes of clock and control registers, and 113

bytes of general purpose RAM.

2.2.5 EEPROM

The EEPROM used is 24C08. The memory is internally organized as 1024 x 8

(8K). It has a 2-wire serial interface. It is guided on the basis of Bi-directional Data

Transfer Protocol. There is a write protect pin for hardware data protection. It has 16-

byte page write modes. It is highly reliable. Endurance is 1 Million Write Cycles. Data

retention is 100 years. There is 3 address inputs A0-A2. The Write Protect (WP) pin

allows normal read/write operations when connected to ground (GND). When the

Write Protect pin is connected to VCC, the write protection feature is enabled. SCL is

the serial clock input. SDA is the serial data.

Figure 2.5 Pin diagram of EEPROM



2.2.6 LCD MODULE

Figure 2.6 LCD Display

In recent years the LCD is finding widespread use replacing LEDs. This is due to

the following reasons:

The declining price of the LCDs.

The ability to display numbers, characters and graphics. This is in contrast to

LEDs, limited to displaying only numbers to few characters.

Features

• + 5V power supply (Also available for + 3V)

• 1/16 duty cycle

• To be driven by pin 1, pin 2 or pin 15, pin 16

LCD pin descriptions

These are the 16 pins and they are given below along with their basic functions

and symbols used to represent them.

PIN

NUM

BER

SYMBOL FUNCTION

1 Vss GND

2 Vdd + 3Vor + 5V

3 Vo Contrast Adjustment

4 RS H/L Register Select Signal



5 R/W H/L Read/Write Signal

6 E H ->L Enable Signal

7 DB0 H/L Data Bus Line








15 A/Vee + 4.2V for LED/Negative Voltage Output

16 K Power Supply for B/L (OV)

Table 2.1 Lcd pin discription

Vcc, Vss, Vee

The Vcc or Vdd pin is used to provide supply of +5V, Vss is the ground pin and

the Vee or Vo is used for controlling LCD contrast.

RS, Register Select

There are 2 very important types of register inside the LCD. The RS pin is used

for their selection as follows. If RS=0, the command code register is selected. If RS=1,

the data register is selected, allowing user to send data to be displayed on the LCD.

R/W, Read/Write

R/W input allows the user to write the information to the LCD or read

information from it. If this pin is set high then read will be selected, else if zero implies

write.

E, Enable

This pin is used by the LCD to latch information presented to its data pins. When

data is supplies to data pins, a high to low pulse must be applied to this pin in order for

the LCD to latch in the data present in the data pins. This pulse must be a minimum of

450ns wide.

DO - D7, Data lines



The 8-bit data pins, DO - D7, are used to send information to the LCD or read

the contents of the LCD's internal registers. To display letters and numbers, we send

ASCII codes for the letters A - Z, a - z, and numbers 0 - 9 to these pins while making

RS = 1. There are also instruction command codes that can be sent to the LCD to clear

the display or force the cursor to the home position or blink the cursor. We also use RS

= 0 to check the busy flag bit to see if the LCD is ready to receive information The

busy flag is D7 and can be read when R/W = 1 and RS = 0, as follows: if R/W = 1,RS =

O. When D7 = 1 (busy flag =1 ) , the LCD is busy taking care of internal operations

and will not accept any new information.

2.2.7 MAX 232

It meets or Exceeds TIA/EIA-232-F and ITU. It operates from a single 5-V

power supply with 1.0µF Charge-Pump Capacitors. It can operate up to 120 kbit/s. It

has two drivers and two receivers and 30-V input levels. It works at low supply current

8 mA typical. ESD Protection Exceeds JESD 22. 2000-V Human-Body Model A114A.

Upgrade with improved ESD (15-kV HBM) and 0.1µF Charge-Pump capacitor is

available with the MAX202.

2.2.8 KEYPAD ENCODER

The MM74C922 and MM74C923 CMOS key encoders provide all the

necessary logic to fully encode an array of SPST switches. The keyboard scan can be

implemented by either an external clock or external capacitor. These encoders also

have on-chip pull-up devices which permit switches with up to 50 kW on resistance to

be used. No diodes in the switch array are needed to eliminate ghost switches. The

internal debounce circuit needs only a single external capacitor and can be defeated by

omitting the capacitor. The Data available output returns to a low level when the

entered key is released, even if another key is depressed. The Data available will return

high to indicate acceptance of the new key after a normal debounce period; this two-

key roll-over is provided between any two switches. An internal register remembers the

last key pressed even after the key is released. The 3-STATE outputs provide for easy

expansion and bus operation and are LPTTL compatible.



Figure 2.7 74C922 Encoder

Features

50 kW maximum switch on resistance

On or off chip clock

On-chip row pull-up devices

Keybounce elimination with single capacitor

Last key register at outputs



CHAPTER 3

CIRCUIT DIAGRAM

3.1 Circuit Diagram

Figure 3.1 Circuit diagram



3.2 Working

Microcontroller reads time from real time chip DS12887. Whenever a RFID tag

is brought near RFID module, it sends the card number in ASCII fomat to the

microcontroller. The microcontroller compares this number with those numbers in the

EEPROM. If match is found, it first check whether it is a master card, then it displays

menu for master card. If not, it displays the ID number and then sends the time and date

details along with ID number to EEPROM for marking daily attendance. If no matches

found, the microcontroller displays ‘Card Not Programmed’ in LCD.

Master card menu consists of set time, add, edit, delete, transfer. The various

options are selected using the keypad keys- up, down, enter, cancel. Keypad encoder

converts the key pressed into corresponding hex file. The output from RFID is given as

the serial input. The card ID number is 8 bytes long and two extra bytes serve as start

and stop bits.

Set time: It is used to edit the time of RTC. The time is entered using the keypad.

Add: It is used to add a new tag and store the new tag number and ID number to

EEPROM.

Edit: It is used to edit the card ID number. The new ID number is entered through

keypad.

Delete: It is used to delete a card from record.

Transfer: This option is used to transfer the marked attendance stored in EEPROM to

the computer.

MAX232 is used to convert the TTL voltage to RS232 compatible voltage. Real

time clock is used to provide the date, month, and year details for marking the

attendance.



CHAPTER 4

PROGRAM FLOW CHART



CHAPTER 5

PROGRAM

#include<reg52.h>#include<aBsacc.h>

//----------------------- PORT DECLARATION ---------------------------------------------------//sfr ldata = 0xA0;sbit RS = P1^4;sbit EN = P1^5;sbit sda = P3^5;sbit sclk = P3^4;sbit IN = P1^6;

//---------------------------------- GLOBAL VARIABLES ----------------------------------------------------//unsigned char hr,min,sec,day,mnt,yr;unsigned char code1,laddr,l2addr,addr,data1[8];unsigned char nadd=0,nedit=0,ndel=0,w,r,choice=0;unsigned char dwaddr[]={0xA0,0XA2,0XA4,0XA6},draddr[]={0XA1,0XA3,0XA5,0XA7};

//---------------------------------- DISPLAY MESSAGES ----------------------------------------------------//code unsigned char msg0[]={"ATTENDANCE-SYSTEM"};code unsigned char msg1[]={"CARD NOT-PROGRAMMED"};code unsigned char msg2[]={"DETECTED CARD-NO"};code unsigned char msg3[]={"MASTER CARD- MENU"};code unsigned char *msg4[]={"SET TIME"," ADD","EDIT","DELETE","TRANSFER"};code unsigned char msg5[]={"SHOW CARD-TO DELETE"};code unsigned char msg6[]={"ENTER HOUR -0~24"};code unsigned char msg7[]={"ENTER MINUTES -'00~59'"};code unsigned char msg8[]={"ENTER DAY -'01~31'"};code unsigned char msg9[]={"ENTER MONTH -'01~12'"};code unsigned char msg10[]={"ENTER YEAR -'00~99'"};code unsigned char msg11[]={"SHOW CARD-TO ADD"};code unsigned char msg12[]={"SHOW CARD-TO EDIT"};code unsigned char msg13[]={"ENTER THE- ID NO"};code unsigned char msg14[]={"CARD ADDED"};code unsigned char msg15[]={"CARD EDITED"};code unsigned char msg16[]={"RECORD -MEMORY FULL"};



code unsigned char msg17[]={"SENDING DATA.."};code unsigned char msg18[]={"DELETE DATA?"};code unsigned char msg19[]={"DATA DELETED"};

//------------------------------------ FUNCTION PROTOTYPE -------------------------------------------------//void msdelay(unsigned int);void lcdcmd( unsigned char);void lcddata( unsigned char);void lcdinit();void display(unsigned char []);void bcdascii(unsigned char);void hexascii(unsigned char);unsigned char hexbcd(unsigned char);void nop(void);unsigned char checkcard();void prog();void senddetails();void settime();unsigned char input(unsigned char);void added();void edited();void sendcode(unsigned char);void sendadd(unsigned char);void start_s_eeprom();void send_byte_s_eeprom(unsigned char);unsigned char get_byte_s_eeprom();void stop_s_eeprom();void send_to_mem(unsigned char, unsigned char);unsigned char get_from_mem(unsigned char);void transmit();void serial(unsigned char);void del();

//----------------------------------- SERIAL INTERRUPT ----------------------------------------------//

void serialintr() interrupt 4{

unsigned char num,j; static int l=0;

if(TI ==1) T1=0; else{ num=SBUF;



if(num!=0x0D && num!=0x0A){

data1[l]=num;l++;

}else if(num==0x0D)

if(l==8){

if(nadd==1)added();

else{

j=checkcard();if(j==0)display(msg1);else if(j==1){ if(nedit==1)

edited(); else if(ndel==1) del(); else {

senddetails(); display(msg2); hexascii(code1);

}}elseprog();

}l=0;lcdcmd(0x01);

}RI=0;

}}

//-------------------------------------Main Program-------------------------------------------------------

void main(){ msdelay(80);

TH1= -3;TMOD=0x20;SCON=0x50;TR1=1;



IE=0x90;lcdinit();w=0;r=0;laddr=get_from_mem(0xFD);msdelay(4);w=get_from_mem(0xFE);msdelay(4);l2addr=get_from_mem(0XFF);msdelay(4);r=1;display(msg0);lcdcmd(0x01);while(1){

hr=XBYTE[4]; bcdascii(hr); lcddata(':'); min=XBYTE[2]; bcdascii(min); lcddata(':'); sec=XBYTE[0]; bcdascii(sec); lcdcmd(0xC0); day=XBYTE[7]; bcdascii(day); lcddata('-'); mnt=XBYTE[8];

bcdascii(mnt); lcddata('-'); yr=XBYTE[9]; lcddata('2'); lcddata('0'); bcdascii(yr); lcdcmd(0x80);}

} //-----------------------------Function Definition-------------------------------------------------

void msdelay(unsigned int td){ unsigned int i,j; for(i=0; i<td; i++) for(j=0; j<1275; j++);}

void lcdcmd( unsigned char value)



{ ldata=value; RS=0; EN=1; msdelay(1); EN=0; msdelay(60);}

void lcddata( unsigned char value){ ldata=value; RS=1; EN=1; msdelay(1); EN=0; msdelay(60);}

void lcdinit(){ lcdcmd(0x38); lcdcmd(0x0E); lcdcmd(0x01); lcdcmd(0x06); lcdcmd(0x80);}

void display(unsigned char msg[]){ short int i=0; lcdcmd(0x01);

lcdcmd(0x80); while(msg[i]!='\0') {

if(msg[i]=='-')lcdcmd(0xC0);elselcddata(msg[i]);i++;

}}

void bcdascii(unsigned char num){

unsigned char x,y;x=num&0x0F;



x=x|0x30;y=num&0xF0;y=y>>4;y=y|0x30;if(choice==0){

lcddata(y); lcddata(x); } else { serial(y);

serial(x); }} void hexascii(unsigned char val){

unsigned char x,y,z;x=val/100;val=val%100;y=val/10;z=val%10;x=x|0x30;y=y|0x30;z=z|0x30;if(choice==0){

lcddata(x); lcddata(y); lcddata(z); } else { serial(x);

serial(y); serial(z); }}

unsigned char hexbcd(unsigned char num){

unsigned char n[2];n[1]=num/10;n[0]=num%10;n[1]=n[1]<<4;num=n[1] | n[0];



return num;}

void nop(void){}

unsigned char checkcard(){

unsigned char a=0,data2[8],flag=0,taddr,temp1,temp2;unsigned char i,j;temp1=w;temp2=r;w=0;r=0;for(addr=0x00;addr<=laddr;){

flag=0;taddr=addr;for(i=0;i<9;i++){ if(i!=8)

data2[i]=get_from_mem(taddr++); else code1=get_from_mem(taddr++);

}

for(j=0;j<8;j++)if(data1[j]!=data2[j])flag=1;if(flag==0){ if(addr==0x00) a=2; else a=1;

break;}elseaddr=taddr;

}w=temp1;r=temp2;return a;

}

unsigned char input(unsigned char c){

unsigned char count=1,n1,num=0,c1[]={1,10,100};



while(count<=c){

while(IN==0);while(IN==1);n1=P1;n1=n1&0x0F;if(c==1)

break;else if(n1<0x0A){

if(count==1){

num=n1*c1[(c-1)]; count++;}else if(count==2){num=num+n1*c1[(c-2)];count++;}else{num=num+n1;count++;

} } } if(c==1) return n1; else return num; }

void prog(){

unsigned char k=0,inp;display(msg3);display(msg4[k]);

do{ display(msg4[k]); inp=input(1); if(inp==0x0C) {

if(k==0)



k=4;elsek--;

} else if(inp==0x0D) {

k++;if(k>4)k=0;

} else if(inp==0x0F) break;

else if(inp==0x0E) { switch(k) {

case 0: settime(); break;

case 1: display(msg11); nadd=1; break;

case 2: display(msg12); nedit=1; break; case 3: display(msg5); ndel=1; break; case 4: display(msg17); transmit(); break;

} break; }

}while(inp!=0x0F);}

void settime(){

msdelay(80);XBYTE[10]=0x20;XBYTE[11]=0x83;display(msg6);hr=input(2);hr=hexbcd(hr);display(msg7);min=input(2);min=hexbcd(min);



display(msg8);day=input(2);

day=hexbcd(day);display(msg9);mnt=input(2);mnt=hexbcd(mnt);display(msg10);yr=input(2);yr=hexbcd(yr);XBYTE[0]=0x00;XBYTE[2]=min;XBYTE[4]=hr;XBYTE[7]=day;XBYTE[8]=mnt;

XBYTE[9]=yr;XBYTE[11]=0x03;

}

void added(){

unsigned char i=0,k,taddr;taddr=laddr;display(msg13);k=input(3);display("Adding");

for(i=0;i<8;i++) { send_to_mem(taddr+i,data1[i]); stop_s_eeprom(); msdelay(4); // page write } send_to_mem(taddr+8,k);

stop_s_eeprom(); msdelay(4);

display(msg14); laddr=laddr+0x09; send_to_mem(0xFD,laddr); stop_s_eeprom();

msdelay(4); nadd=0;

}

void edited(){

unsigned char k,caddr;display(msg13);k=input(3);caddr=addr+0x08;



display("Editing");send_to_mem(caddr,k);stop_s_eeprom();

msdelay(4);display(msg15);nedit=0;

}

void del(){ unsigned char i=0,taddr; taddr=addr; send_to_mem(taddr,0xFF); for(i=1;i<7;i++) // page write send_byte_s_eeprom(0xFF); stop_s_eeprom(); msdelay(4); send_to_mem(taddr+7,0xFF); send_byte_s_eeprom(0xFF); stop_s_eeprom(); msdelay(4); display(msg19); ndel=0;} void senddetails(){ if(w<4) { start_s_eeprom(); send_byte_s_eeprom(dwaddr[w]); send_byte_s_eeprom(l2addr); send_byte_s_eeprom(code1); send_byte_s_eeprom(hr); send_byte_s_eeprom(min); send_byte_s_eeprom(day); send_byte_s_eeprom(mnt); send_byte_s_eeprom(yr); stop_s_eeprom(); msdelay(4); l2addr+=7; if(l2addr==0xFC) { w+=1; if(w==4) l2addr=0xFC;



else l2addr=0x00; } send_to_mem(0xFE,w); stop_s_eeprom(); msdelay(4); send_to_mem(0xFF,l2addr); stop_s_eeprom(); msdelay(4); } else display(msg16);} void transmit(){

unsigned char i,num,temp,addr2=0x00;choice=1;temp=w;if(temp==4)temp--;w=1;r=1;

do{

serial('@');for(i=0;i<7;i++){ num=get_from_mem(addr2++);

if(i==0) hexascii(num); else bcdascii(num);

} serial('#'); msdelay(4); if(w==temp) if(addr2>=l2addr) break; if(addr2==0xFC)

{ w+=1; r+=1; addr2=0x00; } }while(w<=temp);



choice=0;display(msg18);if(input(1)==0x0E)

{ l2addr=0x00; w=1; r=1; display(msg19); } }

void serial(unsigned char n){

SBUF=n;while(TI==0);TI=0;

} void send_to_mem(unsigned char s_address,unsigned char s_data) { start_s_eeprom(); send_byte_s_eeprom(0XA0); send_byte_s_eeprom(s_address); send_byte_s_eeprom(s_data); // stop_s_eeprom(); } unsigned char get_from_mem(unsigned char s_address) { unsigned char i = 0; //-------dummy write seq----+ word address------------------------------------ start_s_eeprom(); send_byte_s_eeprom(dwaddr[w]); send_byte_s_eeprom(s_address); //----------------dummy over----------------------------------------------------

start_s_eeprom(); send_byte_s_eeprom(draddr[r]); i = get_byte_s_eeprom(); stop_s_eeprom(); return(i); } void send_byte_s_eeprom(unsigned char s_byte) { unsigned char temp = s_byte;



unsigned char i,j;

for(i = 8 ; i > 0 ; i--) { j=i-1; temp = s_byte; temp = temp >> j; temp = temp & 0X01; if(temp == 0) sda = 0; else sda = 1; sclk = 1;

nop(); nop(); nop();

sclk = 0; } sda = 1; nop(); sclk = 1; nop(); nop(); nop(); sclk = 0; }

unsigned char get_byte_s_eeprom() { unsigned char temp, temp_h, i,j; temp = 0; temp_h = 1; sda = 1; for(i = 8; i >0 ; i--) { j=i-1; sclk =0; nop(); nop(); nop(); nop(); sclk = 1; if(sda == 1) temp = temp | temp_h<<j ; }



sclk = 0; return(temp); }

void start_s_eeprom() { sda = 1; sclk = 1; nop(); nop(); nop(); sda = 0; nop(); nop(); nop(); sclk = 0; }

void stop_s_eeprom() { sda = 0; nop(); nop(); nop(); sclk = 1; nop(); nop(); nop(); sda = 1; }



FABRICATION OF PCB

Making a Printed Circuit Board is the first step towards building electronic equipment by any electronic industry. We should keep in mind that quality of soldering affects the quality of the output. The procedure for fabricating the PCB for setting up the circuit of any multipurpose project is described below.

PCB Making:

The making of PCB is as much as art on a technique particularly so when they are to fabricated in very small numbers. There are several ways of drawing PCB patterns and making the final boards.

The making of PCB essentially involves two steps:

1. Preparing PCB drawing

2. Fabricating PCB from the drawing

The traditional method of drawing with complete placement of parts, taking a photographic negative of the drawing, developing the image of the negative formed on photo sensitized copper plate and dissolving the excess copper by etching is a standard practice being followed by large scale operations. However for small-scale operations, where large numbers of copies are not required, the cost saving method presented here may be adopted.

PCB Drawing:

Making of PCB drawing involves placement of components, locating holes, optimum area each component should occupy shape and size of pads for the components, track size and spacing and prevention of overcrowding of components at a particular area. With these details the sketch of the PCB is made. For anchoring leads of component 1mm diameter holes and for fixing PCB holding screws to the 3mm holes diameter can be made. Following these hints, a sketch of PCB is made.

PCB Fabrication:



The fabrication of the PCB starts by transferring the PCB drawing onto a copper clad sheet. For a small number of PCB, a direct photographic transfer of the PCB drawing from a negative image of the drawing to a photo sensitized copper clad sheet is carried out. The copper from the unexposed area is later etched away. For large quantity production, screen printing method is used to transfer the PCB drawing image to the copper clad sheet. For etching the copper clad sheet 20-30grms of ferric chloride 75ml of water heated to about 60degree Celsius may be used . The copper clad sheet is placed in the solution with its copper side upwards in a plastic tray. Stirring the solution helps in speedy etching. The dissolution of unwanted copper would take about 45min. If etching takes longer, the solution may be heated again and the process is repeated. The paint on the pattern can be removed by rubbing with a rag soaked in thinner, turpentine or acetone. The PCB can then be washed and dried.

The pads are drilled with proper drill sizes of 0.9mm, 1mm, 3mm etc for

the leads and mounting holes.



CHAPTER 6

MERITS AND DEMERITS

Advantages

Unauthorized attendance can be avoided.

Easy to verify the attendances over a long period of time.

Promiscuity of tags.

Non-contact and non-line-of-sight.

Space consumption can be reduced to a greater extent.

No need to connect this system to a P.C always.

Disadvantages

Identity theft.

System affected by metal interference.

Very little power available to digital portion of the IC, limited functionality.

Lack of standards and protocols



CHAPTER 7

FUTURE ENHANCEMENT

Protocols may be rolled out which make tags obstinate to power interruption

and fault induction. Power loss graceful recovery of tags can be implemented. Research

works could be conducted on smart cards and other embedded systems. Many

multitudes of labour can be done associating low cost hardware. Improved memory

storage can make it possible to mark the attendances of a large group of people, without

connecting to the system. By using active tags or using high frequency RFID readers,

the range can be increased.



APPENDIX



AT89C52

Features• Compatible with MCS-51™ Products• 8K Bytes of In-System Reprogrammable Flash Memory• Endurance: 1,000 Write/Erase Cycles• Fully Static Operation: 0 Hz to 24 MHz• Three-level Program Memory Lock• 256 x 8-bit Internal RAM• 32 Programmable I/O Lines• Three 16-bit Timer/Counters• Eight Interrupt Sources• Programmable Serial Channel• Low-power Idle and Power-down Modes

Description

The AT89C52 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer.



Absolute Maximum Ratings

Operating Temperature.......................................... -55°C to +125°C Storage Temperature ............................................. -65°C to +150°CVoltage on Any Pin with Respect to Ground .........-1.0V to +7.0VMaximum Operating Voltage .................................. 6.6VDC Output Current................................................... 15.0 mA

DC CHARACTERISTICS



External Program and Data Memory Characteristics

74C922- 16 KEY ENCODER

These CMOS key encoders provide all the necessary logic to fully encode an array of SPST switches. The keyboard scan can be implemented by either an external clock or external capacitor. These encoders also have on-chip pullup devices which permit switches with up to 50 kX on resistance to be used. No diodes in the switch array are needed to eliminate ghost switches. The internal debounce circuit needs only a single external capacitor and can be defeated by omitting the capacitor. A Data Available output goes to a high level when a valid keyboard entry has been made. TheData Available output returns to a low level when the entered key is released, even if another key is depressed. The Data Available will return high to indicate acceptance of the new key after a normal debounce period; this two-key rollover is provided between any two switches. An internal register remembers the last



key pressed even after the key is released. The TRI-STATEÉ outputs provide for easy expansion and bus operation and are LPTTL compatible.

Features 50 kX maximum switch on resistance On or off chip clock On-chip row pull-up devices 2 key roll-over Keybounce elimination with single capacitor Last key register at outputs TRI-STATE outpust LPTTL compatible Wide supply range 3V to 15V Low power consumption



DC Electrical characteristics



EEPROM 24C08

Features• Low-voltage and Standard-voltage Operation –2.7 (VCC = 2.7V to 5.5V) – 1.8 (VCC = 1.8V to 5.5V)• Internally Organized 128 x 8 (1K), 256 x 8 (2K), 512 x 8 (4K), 1024 x 8 (8K )

or 2048 x 8 (16K)• 2-wire Serial Interface• Schmitt Trigger, Filtered Inputs for Noise Suppression• Bi-directional Data Transfer Protocol• 100 kHz (1.8V) and 400 kHz (2.5V, 2.7V, 5V) Compatibility• Write Protect Pin for Hardware Data Protection• 8-byte Page (1K, 2K), 16-byte Page (4K, 8K, 16K) Write Modes• Partial Page Writes are Allowed• Self-timed Write Cycle (5 ms max)• High-reliability – Endurance: 1 Million Write Cycles – Data Retention: 100 Years• Automotive Grade, Extended Temperature and Lead-free/Halogen-free Devices Available• 8-lead PDIP, 8-lead JEDEC SOIC, 8-lead MAP, 5-lead SOT23, 8-lead TSSOP and 8-ball dBGA2™ Packages

Absolute Maximum RatingsOperating Temperature...................................... -55° C to +125°C Storage Temperature ......................................... -65° C to +150°CVoltage on Any Pin with Respect to Ground ...-1.0V to +7.0VMaximum Operating Voltage ............................ 6.25VDC Output Current............................................. 5.0 mA



Real time clock DS12887

FEATURES Drop-in replacement for IBM AT computer clock/calendar Pin compatible with the MC146818B and DS1287 Totally nonvolatile with over 10 years of operation in the absence of

power Self-contained subsystem includes lithium, quartz, and support circuitry.



Counts seconds, minutes, hours, days, day of the week, date, month, and year with leap year compensation valid up to 2100

Binary or BCD representation of time, calendar, and alarm 12– or 24–hour clock with AM and PM in 12–hour mode Daylight Savings Time option Selectable between Motorola and Intel bus timing Multiplex bus for pin efficiency Interfaced with software as 128 RAM locations 15 bytes of clock and control registers 113 bytes of general purpose RAM Programmable square wave output signal Bus–compatible interrupt signals (IRQ) Three interrupts are separately software maskable and testable Time–of–day alarm once/second to once/day Periodic rates from 122 ms to 500 ms End of clock update cycle Century register



RFID READER

Features Selectable UART or Wigand26 Plug-and-Play, needs +5V to become a reader No repeat reads LED/Beeper indicates tag reading operation Excellent read performance without an external circuit Compact size and cost-effective A very efficient module for portable readers.

Pin description



Applications of LF DT125R SeriesApplications of the RFID OEM LF DT125R Reader Module are limited

by the imagination of the designer because of the compact form factor and low power consumption. Some of the common applications for this module are:

Access control Handheld readers Asset management Time and Attendance Immobilizers

LCD DISPLAY

Absolute Maximum Ratings



Electrical Characteristics

PIN Description

CHAPTER 8



CONCLUSION

The project RFID based attendance system has been completed and

working has been observed. RFID tag shown over the reader identifies the

person and the code can be entered by the use of keypad. The ID number and

related details are sent to the computer . RFID module comprising of a RFID

Reader and a RF Tag avails an easy implementation option and is a far less

tedious bid. It is a simple method and is reliable. Saving attendance in a

computer allows easy verification and longer record keeping.

REFERENCES



1. The 8051 Microcontroller and Embedded Systems (Second Edition) by

Muhhammad Ali Mazidi, Janice Gillispie Mazidi, Rolin D McKinlay

2. Electric and Electronics Measurement and Instrumentation (Fourth

edition), A.K.Sawhney

3. Kenneth J Ayala, “The 8051 Microcontroller”, Pearson Education.

4. Muhammad Ali Mazzidi, “The 8051 Microcontroller Architecture,

programming and applications”, J.B. Gupta , “Electronic Devices And

Circuits”

5. www.dallas.com

6. www.cornell.com

7. www.electronics4u.com

8. www.datasheet4u.com


http://www.cornell.com/

http://www.dallas.com/

rfid report

Documents

marking attendance

attendance registers

rfid reader module

explanation rfid reader

nattakom project

rfid tags

th rfid reader

circuit diagram