rfid based attndance system

7/28/2019 Rfid Based Attndance System

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1. INTRODUCTION

An attendance recording systems basic function is to keep a record of the time at which the employees

of a particular firm report to work and leave from work. It is one of the most widely used eventrecording application in the industry today. A track of employee attendance is a must for payrollgene333ration. The traditional method of maintaining an attendance register makes the job very tedious

and prone to human errors. The collection and processing of data of employee.

If a system is available by means of which attendance data be stored, accessed, sorted, and processedand obtained in a form of a detailed report which may be used directly for payroll generation, hence

saving a lot of precious time. It functions as a network of microchip smart tags and receivers. Each

smart tag is embedded with a unique electronic product code (EPC) and a micro-antenna. Once

assigned, the EPC becomes a DNA-like marker for the item, identifying it from every other item in theworld. When a tagged item passes within range of a reader, the reader retrieves the EPC via radio

waves, identifies the item and its exact location, and relays this real-time information to a centralcomputer. Taken together, the series of transactions comprise a comprehensive record of the tagged

items movement from point of origin to point of sale.

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 attendancesystem 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 verificationand 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 advantage of this system is simplicity and reliability. Saving attendance in acomputer allows easy verification and longer record keeping.


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2. REQUIREMENTS

2.1 HARDWARE REQUIREMENTS:

AT89S52 7805 CAPACITOR RESISTOR RF MODULES MAX 232

CRYSTAL OSCILLATOR

2.2 SOFTWARE REQUIREMENTS:

KEIL C COMPILER PROGRAMMING IN EMBEDDED C


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3. BLOCK DIAGRAM

Fig 3.1: Block diagram

c

POWER

SUPPLY

COMPUTER SYSTEM

MAX 232

SERIAL PORTRFID READER

MODULE


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4. SCHEMATIC CIRCUIT DIAGRAM

Fig 4.1: Circuit diagram


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5. 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. Themicrocontroller 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 formarking 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 selectedusing 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 thecomputer.

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.

Fig 5.1:RFID System


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6. COMPONENT DESCRIPTION

6.1 RFID READER

The DT125R series RFID Proximity OEM Reader Module has a builtin antenna in minimizedform 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 hostsystems 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 usedin 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. TheManchester 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:


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6.2 Power supply

Circuit diagram of Power Supply

Fig 6.2.1: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 andactive 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.

L2For many applications in electronicsunregulated 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 principle of electromagnetic induction. In addition toperforming 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.


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(2) Bridge rectifier

In the bridge circuit 4 diodes are connected I the form of a Wheatstone bridge. When the upperend 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, thediodes 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 thedistribution problems associated with single point regulation.

6.3 MICROCONTROLLER AT89C52

It has 8K Bytes of In-System Programmable (ISP) Flash Memory. It has an endurance of 1000write 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 userprogram. 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 erasableread only memory (PEROM).

The device is manufactured using Atmels highdensity nonvolatile memory technology and is

compatible with the industry-standard 80C51 and 80C52 instruction set and pinout. The onchipFlash 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 costeffective 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


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In addition, the AT89C52 is designed with static logic foroperation down to zero frequency andsupports 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.

The Accumulator

The Accumulator, as its name suggests, is used as a general register to accumulate the results ofa 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 alonewould 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 DIVinstructions, 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 DataPointer Register.


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The Program Counter (PC)

The Program Counter (PC) is a 2-byte address which tells the 8052 where the next instruction toexecute 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 valueof 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 RAMaddress 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 registers 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 theinternal 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 handleexternal memory depends on the pin EA logic state:


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EA=0.

In this case, internal program memory is completely ignored, only aprogram 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 P2are 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 thesame 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 theinstruction 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 indirectaddressing 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 toperipheral environment.


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T2CONTimer/Counter 2 Control Register

TF2- Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2will 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 negativetransition 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 pulsesfor its receive clock in serial port modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be usedfor 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 beused for the transmit clock.

EXEN2- Timer 2 external enable. When set, allows a capture or reload to occur as a result of anegative 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 transitionsat 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.


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

MAX 232

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

1.0F 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 ProtectionExceeds JESD 22. 2000-V Human-Body Model A114A. Upgrade with improved ESD (15-kV

HBM) and 0.1F Charge-Pump capacitor is available with the MAX202.


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7. INTRODUCTION TO RF

Radio frequency (RF) radiation is a subset ofelectromagnetic radiation with a wavelength of 100km to

1mm, which is a frequency of 3 KHz to 300 GHz, respectively. This range of electromagnetic radiation

constitutes the radio spectrum and corresponds to the frequency of alternating current electrical signals

used to produce and detect radio waves. RF can refer to electromagnetic oscillations in either electrical

circuits or radiation through air and space. Like other subsets of electromagnetic radiation, RF travels at

the speed of light.

7.1 RF COMMUNICATION WORKING:

Imagine an RF transmitter wiggling an electron in one location. This wiggling electron causes a ripple

effect, somewhat akin to dropping a pebble in a pond. The effect is an electromagnetic (EM) wave thattravels out from the initial location resulting in electrons wiggling in remote locations. An RF receiver

can detect this remote electron wiggling. The RF communication system then utilizes this phenomenon by

wiggling electrons in a specific pattern to represent information. The receiver can make this same

information available at a remote location; communicating with no wires. In most wireless systems, a

designer has two overriding constraints: it must operate over a certain distance (range) and transfer a

certain amount of information within a time frame (data rate).

7.2 RF COMMUNICATION:

Widely used, including Bluetooth, Radios, Cell phones, Satellite etc Wide range, from few meters to millions of kilometers (Can be Used to

control Robots in Mars)

2Does not require two devices to be in line of sight. Can cross many obstacles
http://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Radio_spectrumhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Electrical_signalhttp://en.wikipedia.org/wiki/Radio_waveshttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Radio_waveshttp://en.wikipedia.org/wiki/Electrical_signalhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Radio_spectrumhttp://en.wikipedia.org/wiki/Electromagnetic_radiation


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7.3. FREQUENCIES:

Name Symbol Frequency Wavelength Applications

Extremelylow

frequency ELF 330 Hz 10,000

100,000 km

Directly audible when converted tosound, communication with

submarines

Super low

frequencySLF 30300 Hz

1,000

10,000 km

Directly audible when converted to

sound, AC power grids (5060 Hz)

Ultra low

frequencyULF 3003000 Hz 1001,000 km


sound, communication with mines

Very low

frequencyVLF 330 kHz 10100 km


sound (below ca. 20 kHz; or

ultrasound otherwise)

Low

frequencyLF 30300 kHz 110 km

AM broadcasting, navigational

beacons, low FER

Medium

frequencyMF 3003000 kHz 1001000 m

Navigational beacons, AM

broadcasting, maritime and aviation

communication

High

frequencyHF 330 MHz 10100 m

Shortwave, amateur radio, citizens'

band radio

Very high

frequencyVHF 30300 MHz 110 m

FM broadcasting, amateur radio,broadcast television, aviation, GPR

Broadcast television, amateur radio,

mobile telephones, cordless


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Ultra high

frequency

UHF

3003000 MHz 10100 cm

telephones, wireless networking,

remote keyless entry for

automobiles, microwave ovens, GPR

Super highfrequency SHF

330 GHz 110 cm

Wireless networking, satellite links,microwave links, satellite television,

door openers

Extremely

high

frequencyEHF 30300 GHz 110 mm

Microwave data links, radio

astronomy, remote sensing, advanced

weapons systems, advanced security

scanning


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8. INTRODUCTION TO KIEL SOFTWARE

Many companies provide the 8051 assembler, some of them provide shareware version of their

product on the Web, Kiel is one of them. We can download them from their Websites. However, the sizeof code for these shareware versions is limited and we have to consider which assembler is suitable for

our application.

8.1 KIEL U VISION2:

This is an IDE (Integrated Development Environment) that helps you write, compile, and debug

embedded programs. It encapsulates the following components:

A project manager A make facility Tool configuration Editor A powerful debugger

To get start here are some several example programs

8.2.2 BUILDING AN APPLICATION IN UVISION2:

To build (compile, assemble, and link) an application in uVision2, you must:

Select ProjectOpen Project(For example, \C166\EXAMPLES\HELLO\HELLO.UV2)

Select Project - Rebuild all target files or Build target. UVision2 compiles, assembles, and linksthe files in your project.


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8.3. CREATING YOUR OWN APPLICATION IN UVISION2:

To create a new project in uVision2, you must:

Select Project - New Project. Select a directory and enter the name of the project file. Select Project - Select Device and select an 8051, 251, or C16x/ST10 Database Create source files to add to the project. Select Project - Targets, Groups, and Files. Add/Files, select Source

Group1, and add the source files to the project.

Select Project - Options and set the tool options. Note when you select the target device from theDevice Database all-special options are set automatically. You only need to configure the

memory map of your target hardware. Default memory model settings are optimal for most.

Fig 5.7. Command Window


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8.4. APPLICATIONS:

Select Project - Rebuild all target files or Build target.

8.5. DEBUGGING AN APPLICATION IN UVISION2:

To debug an application created using uVision2, you must:

Select Debug - Start/Stop Debug Session. Use the Step toolbar buttons to single-step through your program. You may enter G, main in the

Output Window to execute to the main C function.

Open the Serial Window using the Serial #1 button on the toolbar. Debug your program using standard options like Step, Go, Break, and so on.

8.6. LIMITATIONS OF EVALUATION SOFTWARE:

The following limitations apply to the evaluation versions of the C51, C251, or C166 tool chains. C51

Evaluation Software Limitations:

The compiler, assembler, linker, and debugger are limited to 2 Kbytes of object code but sourceCode may be any size. Programs that generate more than 2 Kbytes of object code will not

compile, assemble, or link the startup code generated includes LJMP's and cannot be used in

single-chip devices supporting Less than 2 Kbytes of program space like the Philips 750/751/752.

The debugger supports files that are 2 Kbytes and smaller. Programs begin at offset 0x0800 and cannot be programmed into single-chip devices. No hardware support is available for multiple DPTR registers. No support is available for user libraries or floating-point arithmetic.


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8.7. EVALUATION SOFTWARE:

Code-Banking Linker/Locator Library Manager. RTX-51 Tiny Real-Time Operating System


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9. 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


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10. 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 alarge group of people, without connecting to the system. By using active tags or using high

frequency RFID readers, the range can be increased.

rfid based attndance system

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