Docstoc

Rfid based security access control system Introduction In this

Document Sample
Rfid based security access control system Introduction In this Powered By Docstoc
					                                                             Rfid based security access control system




                                 1. INTRODUCTION


        In this developing world, safety and security is given prime importance. In the day to day
life there come various situations in which security is being challenged. The need for developing
an error free and cheap security access control system is greatly demanding. It will be a boon in
many sectors like banking, defense, and finance. There are situations in which access must only be
granted to certain authorized persons. Absence of reliable security systems can lead to catastro-
phe. Our project ‘security access control system using rfid ’ is a reasonable solution in terms of
security and access control .this type of security systems are now used in many private sectors.

        Rfid radio frequency identification is a general term that is used to describe a system that
transmits the identity (in the form of a unique serial number) of an object wirelessly, using radio
waves. rfid technologies are grouped under the more generic automatic identification (auto
id)technologies. Radio-frequency identification (rfid) is an automatic identification method, rely-
ing on storing and remotely retrieving data using devices called RFID tags or transponders.

       RFID stands for radio frequency identification, and is contact less storage of small
amounts of data on trivial circuits powered by the reader infrastructure itself. Its most commonly
deployed now a days as a replacement for magnetic swip oriented system, as the lack of an ex-
pensed data structure and the absence of contact during scanning make RFID astonishingly relia-
ble.

        An RFID tag is an object that can be attached to or incorporated in to a product, animal or
person for the purpose of identification using radio waves. All RFID tags contain at least two
parts. One is an integrated circuit for storing and processing information, modulating and demodu-
lating a radiofrequency signal and perhaps other specialized functions. The second is an antenna
for receiving and transmitting the signal. The RFID tag can automatically be read from several
meters away and does not have to be in the line of sight of the reader. An RFID tag consists of
small silicon microchip attached to an antenna. The chip itself can be as small as half a millimeter
squares roughly the size of a tiny seed. Some RFID tags are thin enough to be embedded in paper.




                                                 1
                                                            Rfid based security access control system




          2. Security Access Control System Using Rfid

In the present scenario security access control system are of different type. It includes security
system using keypad, barcode systems and Magnetic card systems. Swiping of card is necessary
for verification of card. There is a chance of occurring error. error may occur due to the speed of
the swiping and angle of the swiping.



There are many disadvantages in using only keypad access.

      Anyone who knows the passwords can access the system
      Possibility of hacking is high
      Once you forget the password the whole system needs to be reset
      There is a possibility of tampering with the keypad


Using the rfid, we can overcome the limitations. In our system there is no need for swiping. So the
error probability is very low compared to other systems. Thus the system is more reliable .it con-
sists of an rfid reader and rfid tags.

         A person who needs to access a door must have an rfid tag with him. The tag is shown to
the reader when a ready message is displayed on the LCD. The microcontroller compares each
digit of number received from the reader and set a flag. For the demonstration purpose we divided
it into three categories. The first is for our HOD, second for our project GUIDE, and the third one
cannot be accessed. in our system the card belonging to HOD gets accessed showing the message
“MR THAJUDDIN WELCOME “ and the door is opened .our PROJECT GUIDE shows a
message “MR SOMASUNDARAN WELCOME” when the corresponding card was shown and
the door is accessed. The third card was denied access to the door. In all the conditions, when the
access is granted, the relay circuit is activated.

        Here an 89c52 microcontroller is used. As this microcontroller has an internal ROM there
is no need for an external ROM. Display used is a 16 x 2 line display capable of displaying alpha-
numeric characters. the relay used is a 5 v




                                                 2
                                                       Rfid based security access control system

                       3. Requirements of the Project
1.                      Hardware Requirements
       semiconductor

RFID/ACCESS CONTROL


Item         Quantity              Reference              Description

1              12            C1,C2,C4,C6,C9,C11,C12,     CAPACITOR 0.1MFD
                             C13,C14,C15,C16,C17
2               1            C3                         CAPACITOR 10MFD
3               1            C5                         CAPACITOR 2200/16V
4               2            C8,C7                      CAPACITOR 30PFD
5               1            C10                         CAPACITOR 100MFD
6               6            D2,D3,D6,D7,D8,D9           DIODE 1N4007
7               2            JP1,JP2                     2PIN SHOWEDED HEADER
                                                        WITH CABLE
8               1            JP3                        6PIN SHOWEDED HEADER
                                                        WITH CABLE
9               1            JP4                        15PIN SHOWEDED HEADER
                                                        WITH CABLE
10              1            J2                         8PIN SHOWEDED HEADER
                                                        WITH CABLE
11              1            J4                         3PIN HEADER
12              1            LS1                         RELAY DS2E-S-DC5V
13              1            Q1                         TRANSISTOR BC548
14              1            RN1                        ( 8x1 RESISROR PACK) RESISTOR
10K
15              1            R1                          RESISTOR
16              1            R2                          RESISTOR 100K
17              1            U1                          IC 40PIN AT89C52
18              2            U12,U2                      IC 20PIN 74HC373
19              1            U3                         IC 28PIN HM62256
20              1            U6                         IC 14PIN 74HC20
21              1            U7                         IC 14PIN 74HC14
22              1            U9                         IC 8PIN MAX485
23              1            U10                        IC 14PIN 74HC08
24              1            U11                        IC 16 PIN DM74LS138
25              1            U13                        IC 20PIN 74LS244
26              1            U14                        IC 28PIN 27C256
27              1            U8                         IC LM7812C/TO220
28              1            U5                         IC LM7805C/TO220
29              1            Y1                         CRYSTAL 11.059MHz
30                                                      IC SOCKETS




                                                3
                                                                  Rfid based security access control system
    COMPONENTS OUTSIDE PCB


1                   1                                         TRANSFORMER 12V
2                   1                                         DISPLAY




3.2 Software Requirements

    We first of all require software to draw the circuit diagram. In the present market there is much soft-
    ware for drawing the circuit and it can also be used to check any errors in the circuit diagram. We also
    need software to draw the PCB layout of the circuit so that the desired PCB can be obtained having
    less complexity. The different software requirements are listed below.



Operating system:

We require an operating system to write the program. OS is essential for the working of other software
such as ORCAD and Kiel. Here the operating system used is windows XP professional.

ORCAD

This software is very useful in drawing the circuit and making the PCB layout. The main advantage of using
ORCAD is its function is simple. It can be very adaptable for a completely new user to this software. We
can try out different combinations of PCB layout of a single circuit and can obtain a more organized lay-
out.



Kiel software

Kiel software is used to convert the program written using 8051 instructions to its hex format so that it
could be embedded to the microcontroller .keil software is very helpful in debugging the program.




                                                     4
                                                                  Rfid based security access control system




4.BLOCK DIAGRAM




Microcontroller

        Here an 89c52 microcontroller is used. As this microcontroller has an internal ROM there is no
need for an external ROM. It has an internal Rom of 8K which is sufficient for the inclusion of the program
requiring for this project. If the program memory is greater then is an additional facility to keep an exter-
nal ROM.

RFID reader and tags



                                                      5
                                                                   Rfid based security access control system

   Rfid reader module continuously produces radio frequency signals. These tags are passive ones and it
contains a embedded circuit and a coil. when the tag come near the field produced by the reader it
gets activated .the data present in the card is send to the reader .the reader gives the details of the
card that is a 26 bit data as output in both Weigand format and RS 485 format.




5. Hardware Description



         The main unit is 89c52 microcontroller. The crystal oscillator circuitries generate the clock pulse
by which all internal operations are synchronized. The reset pin of 89c52 is active high. In order to provide
this a reset circuitry is provided. Crystal oscillator used is having a frequency of 11.059MHz. This particular
frequency crystal oscillator is used to make serial communication easy for further development of the
project.



5.1 Memory Space Decoding

External memory is added to the microcontroller by using port as data and lower order address bus and
port 2 as the higher order address bus. The data and lower address are time multiplexed on port 0. An
external 74HC273 address octal latch is connected to port 0 to store the lower address byte whenever
external memory is accessed. The low order address is gated in to transparent latch by the address latch
enable pulse from the 89c52.ALE is applied to the latch enable pin of 74373.

When internal ROM is not used or if the memory fewer versions, 8051 is used the EA (external access) pin
is connected to Vcc. when 89c52 is used, there is no need for an external ROM since it has 8k of external
ROM.

Entirely different control lines from the microcontroller address RAM and ROM. PSEN for the ROM and
RD and RD and WR for the RAM differentially select the components according to the instructions exe-
cuted.

5.2 Accessing External RAM



External RAM is to be connected in parallel sharing the same address latch output, except pins CE, OE,
and W. In this case the CE RAM pin is not connected to an “external output decoding circuit that activates



                                                       6
                                                                   Rfid based security access control system

low level whenever the 89c52 devices RD or WR low meaning READ from or WRITE to the external RAM
chip.

To write into the RAM the 89C52 post the high order address 8 bit at P2 the low order address 8 bit at P0,
pulse up ALE to store P0 at the latches, then post the data to be written at P0 and pulse WR low this WR
low need to be translated the “external address decoding circuit “into –W, +OE and –CE to the RAM .this
stores the byte from P0 into the RAM addressing by P2 and the output of 74HC373.

To read from the RAM, the 89C52 does the same addressing , but now it only pulses low and RD pin and
the “external address decoding unit” translates it into +W, +OE and –CE to the RAM. This reads the ram
and its contents are posted at the RAM output ,so 89C52 reads this byte available at the port P0 input
pins.0000h to 7ffffh is the memory locations address of the interfaced external SRAM .apart from the
RAM ,the 64 k module is a 16 character x 2 line output device .it is also addressed by the MOVX instruc-
tion .so in order to select the correct components decoding is done.

The upper 4 bits of the address bus is A15, A14, A13, A12 are given into a four input NAND gate. The out-
       put of this is fed as t he enable signal E, for a 3 to 8 decoder (74LS138) the output of the NAND
       gate is inverted (using 74HC20) and is used as the chip enable (CE) line of the RAM.

When CE of RAM is enabled and if the WR or RD pin goes low then writing or reading of data from the
      addressed memory location takes place

In the 74138, 3 to 8 decoder, address line A8, A9, A10 are the input lines .the Y1 output line of the De-
        coder is used as the enable line for the LCD module. So the enabling of LCD is done when the bit
        assignment of address is F100 done when the address bus is F100h.

In order to write data that has to be displayed on the LCD RAM an octal latch that is selected on WR signal
        (low) is used .to input the instruction and data separately into the LCD, register select (RS) input
        is given as the 7th bit of port 1 P1.6 is high data input is taken as the ASCII data that is to be dis-
        played.

RFID tags are used as a key to open a lock and RFID reader is taken as a lock. When the tag is shown to
        the reader, it identifies the tag and sends a corresponding data to the microcontroller.

Interfacing of RFID reader with microcontroller is done with the help o f an AND gate. We used WEIGAND
        output format. When data is available on the output pin of the reader, the microcontroller will
        get interrupted. The data pins are connected to 0th pin and 1st pin of PORT1.fromthese pins mi-
        crocontroller reads the 26 bit data and process the same.

Microcontroller

A microcontroller is a computer on chip or, if you prefer, a single chip computer. micro suggests that the
       device might be used to control objects, processors or events. Another term to describe a micro-
       controller is embedded microcontroller because the microcontroller and its support circuits are
       often built into, or embedded in, the device they control.




                                                       7
                                                                Rfid based security access control system

A microcontroller is similar to the microprocessor inside a personal computer. Example of microprocessor
       includes Intel’s 8086, Motorola‘s 68000, and zilog’s Z80 ATM9C51. The microprocessor and con-
       troller contain a processing unit, or CPU. The CPU executes instructions that perform the basic
       logic math and data moving functions of a computer. To make a complete computer, a micropro-
       cessor requires memory for storing data and programs, and input/output (I/O) interface for con-
       necting external devices like keyboards and displays.

In contrast, a microcontroller is a single chip computer because it contains memory and I/O interfaces in
        addition to the CPU. because the amount of memory and interfaces that can fit on a single chip is
        limited, microcontroller tend to used in smaller systems that require little more than the micro-
        controller and a few support components.

Figure below shows the block diagram of a typical microcontroller.

    ARITHEMETIC           TIMER/               I/O PORTS

    AND LOGIC           COUNTER

ACCUMALATER                                     I/O PORTS

  REGISTERS               INTERNAL ROM         INTRUPT

                                                CIRCUITS

INTERNAL RAM

STACK               PROGRAM                        CLOCK

COUNTER                         CIRCUITS

5.3.1THE 8051 FAMILY

The 8051 family of microcontroller is based on an architecture, which is highly optimized for embedded
       control system. It is used in a wide variety of application from military equipments to automobile
       to keyboard your P.C second only to motorola68HC11in 8 bit processor sales, the 8051 family of
       Atmel, Intel, Philips and Siemens. These manufactures have added numerous features and pe-
       ripherals to 8051such as I2C interfaces, analog to digital converters, watchdog timers and pulse
       width modulation outputs. Variation of the clock seed up to 40 MHz and voltage requirements
       down to 1.5 volts are available

The basic architectures consist of the following features.

        8bit CPU with registers A (accumulator) and B

        16 bit program counter (PC) and data pointer (DPTR)

        18 bit program status word (PSW)




                                                        8
                                                                 Rfid based security access control system

          8 bit stack pointer (SP)

           Internal ROM or EEPROM

Internal RAM of 128 bytes

         4 register bank each containing 8 registers

         16 bytes which may be addressed at byte

         8 bytes for general purpose memory

30 two input /output pins arranged as 4 eight bit ports: P0-P3

Two 16 bit timer / counter T0 and T1

Full duplex serial data receiver/transmitter: SBUF

Control registers: TCON, TMOD,SCON,PCON,IP, and IE

Two external and three internal interrupt sources

PIN DESCRIBTION

The AT89c51 is low power high performance CMOS and bit micro computer with 4K bytes of flash pro-
       grammable and erasable read memory (PEROM). The device is manufactured using Atmel’s high
       density non volatile memory technology and is compactable with the industry standard MCS 51
       instruction set and pins out. The on chip flash allows the program memory to e reprogrammed in
       system or by a conventional non volatile memory programmer. By combining a versatile 8 bit cpu
       with flash on a monolithic chip, the Atmel AT89c51 is a power micro computer which provides a
       highly flexible and cost effective solution to many embedded control applications.

VCC

Supply voltage

GND

Circuit ground potential

Input/output pins, Ports :

Port 0

Port 0 is an 8 bit open –drain bidirectional I/O port. As an output port each pin can sink 8 TTL inputs.
         When 1’s are written to port 0 pin the pin can be used as high-impedance circuits. Port 0 may also
         be configured to be the multiplexed low order address/data bus during accesses to external pro-
         gram and data memory. In this mode P0 has pull-ups




                                                       9
                                                                   Rfid based security access control system

Port0 also receives the code bytes during flash programming and outputs the code byte during program
        verification. External pull-ups are required during program verification.

Port1

Port1 is an 8 bit bidirectional I/O port with internal pull-ups. The port1 output buffers can sink/source4
         TTL inputs. When 1’s are written to port1 pins they are pulled high by the internal pull-up scan be
         used as inputs. As inputs port1 pins that are extremely being pulled low will source current be-
         cause of the internal pull ups.port1 also receives the low order address bytes during flash pro-
         gramming and verification.

Port2

Port2 is an 8 bit bidirectional I/O port with internal pull-ups. The port 2 output buffers can sink/source
         four TTL inputs. When 1’s are written to port2 pins they are pulled high by the internal pull-ups
         and can be used as inputs. As input,port2 pins that are extremely being pulled low will source cur-
         rent because of the internal pull-ups.port2 emit the high order address bytes during fetches from
         external program memory and during accesses to external data memory that uses 16 bit address-
         es (MOVX@DPTR), in this application it uses strong internal pull ups when emitting 1’s. During ac-
         cess to external data memory that uses 8 bit addresses (MOVX@R1) port 2 emits the content of
         the p2 special function register. Port 2 also receives the high order address bits and some control
         signals during flash programming and verification.

Port3

Port3 is an 8 bit bi-directional I/O ports which internal pull-ups. The port3 output buffers can sink/sources
         four TTL inputs. When 1’s are written to port3 pins they are pulled high by the internal pin ups
         and can be used as inputs as input, port pin alternate functions. Port3 pins that are extremely be-
         ing pulled low will source current because of the pull ups . Port3 also serves the functions of vari-
         ous special features of the AT89c51 is listed below.port3 also receives some control signals for
         flash programming and verification.

P3.0    RXD (serial input port)

P3.1    TXD (serial output port)

P3.2    INT0(external interupt0)

P3.3    INT1(external interupt1)

P3.4     T0(timer0 external input)

P3.5     T1(timer1 external input)

P3.6     WR(external data memory write strobe)

P3.7     RD(external data memory read strobe)



                                                       10
                                                                    Rfid based security access control system

RST:

Reset input, a high on this pin for two machine cycles. While the oscillator is running reset the device.

ALE/PROG:

Address Latch enable output pulse for latching the low byte of the address during accesses to external
       memory. This pin is also the program pulse input (PROG) during flash programming.

In normal operation ALE is emitted at a rate of 1/6 the oscillator frequency, and may be used for exter-
       nal timing or clocking purposes. Note however that one ALE pulse is skipped during each access
       to external data memory. If desired ALE operation can be disabled by setting bit0 of SFR location
       8EH.

PSEN: program store enable is the read strobe to external program memory. When the AT89c51 is exe-
       cuting code from external program memory, PSEN is activated twice each machine cycle, except
       that two PSEN activation are skipped during access to external data memory.

EA/VPP:

External access enable. EA must be strapped to GND in order to enable the device to fetch code from ex-
        ternal program memory locations starting at 000h up to FFFFh. Note, however that if lock bit 1 is
        programmed. EA will be internally latched on reset. A will be strapped to internal program execu-
        tions.

This pin also receives the 12-volt programming enable voltage (VPP) during, flash programming for parts
         that require 12-v VPP.

XTALL1:

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XSTALL2:

Output from the inverting oscillator amplifier.




5.3.3.Block Diagram




                                                       11
                                            Rfid based security access control system



Memory Organization



Basic Registers




RADIO frequency identification(RFID)




                                       12
                                                                  Rfid based security access control system



RADIO frequency identification

         RFID - RADIO frequency identification(RFID) is a technology that is rapidly crossing over from be-
ing expensive and experimental to universal usefulness .the basic concept is quite simple :attach small
coiled radio antenna to a microchip and implant it in anything that needs to be read ,scanned ,monitored
,warehoused or alerted . RADIO frequency identification (RFID) is a wireless communication technology
with advanced features ideal for making contact less payments, item tracking, and automatic data collec-
tion.

        Chip tags usually made to work at specific frequencies which are license free. The tolerated
power levels and regulations for these vary from country to country. For example ,the maximum per-
mitted legal power level (the power level at which the interrogator is set at ) for 2.45 GHz in US is
100 times higher than in the Europe . This creates a huge difference in read range –a range in the U.S
may only be a 1 centimeter range in Europe, all else being equal. Therefore, much work still needs to
be done to balance these regulatory issues worldwide, though there is some progress. Similar to barcode
technology RFID has several advantages including more data capacity (up to 16 kbits ),scanning multiple
tags simultaneously ,tag data is read and write , and no line of sight is required between the tags and the
reader.



RFID TAGS

RFID tags are categorized as either active or passive. Active RFID tags are provided by an internal battery
and are typically read/write, i.e., tag data can be rewritten and/or modified. An active tag’s memory size
varies according to application requirements; some systems operate with up to 1MB of memory. In atypi-
cal read/write RFID work in process system, a tag might give a machine a set of instructions, and the ma-
chine would report its performance to the tag. The encoded data would then become part o the tagged
part’s history. The battery supplied power of an active tag generally gives it a longer read range. The trade
off is greater size, greater cost, and a limited operational life.

Passive RFID tags operate without a separate external power source and obtain operating power gener-
ated from the reader. Passive tags are consequently much lighter than active tags, less expensive, and
offer a virtually unlimited operational lifetime. The trade off is that they have shorter read ranges than
the active tags and require a higher powered reader.

Read only tags are typically passive and are programmed with a unique set of data (usually 32 to 12 bits)
that cannot be modified. Read only tags most often operate as a license plate into a database, in the
same way as linear barcode reference a database containing modifiable product specific information.

Passive tag can be made very small and attached to anything that needs a memory or an ID number. RFID
tags come in many shapes and sizes such as thin disks, credit cards or paper labels called smart labels.




                                                      13
                                                                  Rfid based security access control system

RFID READERS

RFID readers can read from and write to RFID tags without contact, even through walls. Read range can
vary from centimeters to several meters, depending on the tags and readers used. Whether portable or
fixed position, readers can read and write multiple tags at one time.

How RFID works

It is a generic term for technologies that use radio waves to automatically identify people or object. There
are several methods of identification but the most common is to store a serial number that identifies
a person or object and perhaps other information on a microchip that is attached to an antennae (
the chip and the antennae together called an RFID transponder or an RFID tag). An RFID system con-
sists of that tag which is made up of a microchip with an antennae , and an interrogator or reader with
an antenna. The antenna enables the chip to transmit the identification information to a reader. The
reader sends out electromagnetic waves. The tag antenna is tuned to receive these waves. There are
three types of RFID tags –active, passive, semi passive. An active RFID tags have a battery ,which is used
to run the microchip’s circuitry and to broad cast a signal to a reader (the way a cell phone transmits
signals to a base station). A passive RFID tag draws power from field created by the reader and uses it to
power the microchips circuits. Semi passive tag use a battery to run the chips circuitry, but communica-
tive by drawing power from the reader. The chip then modulates the wave that the tag sends back to the
reader. The reader converts the radio waves reflected back from the RFID tag in to digital information
that can then be passed on to computers that can make use of it.



When the RFID tag is activated by a reader device, it transmits information from the chip to a central
computer system which can be about 2kilo bytes of information(less than one tenth of the size of its doc-
ument in my word processor) can be held on a single chip.



Inside an RFID tag is a microchip connected to an antenna. The microchip can store the modest amount of
information up to about 2K bytes.tag come in a variety of from factors and can be attached to anything.
RFID tag can often then used to store a simple identification number. In more sophisticated systems the
tag can function as a portable travelling data base for the item to which it is attached.



RFID readers control the wireless reading and writing of information stored on a RFID tag. Rfid readers
generate an RF field around its antenna. The RF field gives the tag power, a clock and a way to transfer
data to the reader. The tag modulates the readers RF field and the reader detect this, similarly the reader
turns the RF field on and off in the right sequence in the order to write the tag.




                                                      14
                                                                  Rfid based security access control system

5.4.5. A Look at RFID Technology



“RFID at present appears to be an evolutionary rather than revolutionary technology “as Prof Charley fine
said.



Radio frequency identification is a method of remotely storing and retrieving data using devices called
RFID tags the basic technology has been around for several years and it is only recently y that –driven by
the standardization activities and other industry initiatives –RFID has started to gain visibility.



RFID can be broadly categorized to an ‘e-tagging ‘technology. at the fundamental level RFID can be seen
as an evolution from barcodes. Barcodes are the simplest forms of tagging. Using barcodes information
about an item can be captured using optical barcode scanners used in the case of barcodes.



5.4.6. Technological Advantage



Because radio waves are used to sense the tag, RFID has the advantage that no line of sight alignment is
required between the RFID tag and the reader. The RFID reader can read multiple tag simultaneously and
instantly. The tags may be embedded inside an object such as a container or in a garment. Further more
RFID tags can store a lot more information than barcodes. The range of sensing RFID tags from a RFID
reader can vary from a few centimeters to a few meters, depending on the frequency of operation and
type of tags (active or passive). The versatilities of RFID’s can be gauged from the fact that RFID can even
be fabricated to be embedded in a piece of paper.



5.4.7. POTENTIAL OF RFID



There are several application areas where RFID is becoming popular. Some of the application areas where
RFID pilots, or limited rollouts have been initiated, include areas such as fleet management, inventory and
asset management, asset tracking, quality control (tracking and counting articles using RFID) , packaging
,security and access control, hazardous material management, advertising and promotion ,delivery and
smart card based payment systems. The technology is making significant inroads in new and innovative
application areas such as location identification ,keyless vehicle operations, spare part management, pre-
ventive maintenance(RFIDs with integrated temperature/pressure /humidity sensors), a telemetry etc.
the most significant factor, limiting the use of RFID is the cost of tags and readers.



                                                      15
                                                                   Rfid based security access control system




PICTURES




Film label RFID tag strip, ………………..



5.4.8RFID READERS AND TAGS USED IN THE PRESENT PROJECT



Here the diagrams and specifications of the RFID reader and tags which are affordable to common citi-
zens.




FIGURES



5.5. Interfacing an LCD to Microcontroller



In the recent years LCD is finding wide spread use replacing LED’s(seven segment LED’s or multisegment
LED’s) this is due to the following reasons

1. Declining prices of LCD’s

2. The ability to display numbers graphic and characters

3. Incorporation of a refreshing controller to the LCD , there by releavi ng the CPU of the task of refresh-
ing the LCD

4. Ease of programming for characters and graphics.



5.5.1 LCD pin description.




                                                      16
                                                                  Rfid based security access control system

VCC ,VSS,&VEE

While vcc &vss provides +5v and ground respectively.vee is used for controlling the contrast of the LCD



RAS, register select:

There are two very important registers in is side the LCD. The RS pin is used for their selection. If RS=0
,the instruction command code register is selected ,allowing the user to send a command such as
clear display ,cursor at home, etc . If RS = 1 the data register is selected, allowing the user to send data
which is 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 the information from it .R/W =0
when writing

E,enable :

         The enable pin is used by the LCD to latch the information presented to its data pins. When data
is supplied to the data pins , a high to -low pulse must be applied to this pin in order for then LCD to
latch in the data present at the data pins. This pulse must be reduced to a minimum of 450ns wide.

D0-D7:

        The eight bit data pins 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 of letters A-Z and 0-9
to these pins while making RS=1




                                                      17
                            Rfid based security access control system




Software description




                       18
                                                               Rfid based security access control system




Programming language section

        The next unavoidable section in software design is the programming language. In this project the
selected language is assembly language. Assembly language is unlike the high level programming is
tied very closely to the physical make up of the processing chip.

        Assembly language is usually written in instruction mnemonics. Once a program has been writ-
ten in mnemonics, it is translated into machine code by a process called assembling the program.



Reasons for selecting assembly language

    Increase the speed of execution
    To reduce the size of the program

   The instruction set used is 8051 instruction set and the assembler used is 8051 assembler.




   PROGRAM

   :pogram for access control system



   Org 0h

   readflag bit 20h.1

   ljmb start




                                                   19
                                    Rfid based security access control system

org 0003h

JNB p1.0, HERE

setb c

rlc a

inc r6

cjne r6,#26,next2

sjmb exit

next2:djnz b, intback

sjmb byte

HERE: clr c

         rlc a

         inc r6

         cjne r6,#26, next 1

         sjmb exit

next 1:djnz b,intback

          sjmb byte

exit:setb readflag

ret i

intback :reti

byte:mov @R1,a

inc r1

mov b,#8

reti



; initialization of display




                               20
                            Rfid based security access control system

Start: lcall delay 1

clr p1.6

mov dptr,#0f100h

mov a,#30h

movx @dptr,a

lcall delay

mov a,#30h

movx @dptr,a

lcall delay

mov a,#38h

movx @dptr,a

lcall delay

mov a,#0ch

movx @dptr,a

lcall delay

mov a,#02h

movx @dptr,a

lcall delay

mov a,#01h

movx @dptr,a

lcall delay

mov a,#80h

movx @dptr,a

lcll delay

setb p1.6




                       21
                                 Rfid based security access control system



;displaying ready message

Ready: mo a,#80h

local cmd

mov a,#01h

lcall cmd

mov a,#52h ; ‘R’

lcall dwr

mov a,#45h ‘e’

lcall dwr

mov a,#41h ‘a’

lcall dwr

mov a,#44h ‘d’

l call dwr

clr readflag

clr p1.2

mov R0,#31h

mov R1,#31h

mov R7,#00h,

mov b,#08

mov R6,#00h

clr a

mov tcon,#01h

init:mov ie#81h

: port reading




                            22
                          Rfid based security access control system

yy:jb readflag,SS

sjmb yy

SS:ljmb dis

dis clear readflag

r1 a

r1 a

r1 a

r1 a

r1 a

r1 a

mov R1,#33h

mov !@R1,a



;discarding bits

rlc a

dec R1

mov a,@R1

rlc a

mov @R1,a

dec R1

mov @a,R1

rlc a

mov @R1,a

dec R1

mov a,@R1




                     23
                       Rfid based security access control system

rlc a

mov @R1,a

; display

mov a,#01h

lcall cmd

mov r0,#30h

aga : mov a,@r0

ani a,#0f0h

rr a

rra

rra

rra

mov b,a

subb a,#09h

jc dec1

mov a,b

add a,#37h

sjmb u1

dec1: mova,b

add a,#30h

u1:lcall dwr

mov a,@r0

an1 a,#0fh

mov b,a

sub a,#09h




                  24
                               Rfid based security access control system

jc dec2

mov a,b

add a,#37h

sjmb U2

dec 2:mov a,b

add a,#30h

U2:lcall dwr

inc r0

cjne r0,#33h,aga

mov a,32h

cjne a,#6Bh ,invalid

lcall mrtag

sjmp valid

;display access granted

valid: mov a,#80h

lcall cmd

mov a,#01h

lcall cmd

setb p1.0

setb p1.2

mov a,# ‘w’

lcall dwr

mov a, ‘E’

lcall dwr

mov a,# ’L’




                          25
                              Rfid based security access control system

lcall dwr

mov a,# ‘C’

lcall dwr

mov a,# ‘O’

lcall dwr

mov a,# ‘M’

lcall dwr

mov a,# ‘E’

lcall dwr

lcall delay1

lcal delay1

lcall delay1

lcall delay1

lcall delay1

jmp ready

;display access denied

Invalid :mov a,#80h

lcall cmd

setb p1.1

mov a,#41h;’a’

lcall dwr

mov a,#43h;’c’

lcall dwr

mov a,#43h;’c’

lcall dwr




                         26
                       Rfid based security access control system

mov a,#45h;’e’

lcall dwr

mov a,#53h;’s’

lcall dwr

mov a,#20h; ‘ ‘

lcall dwr

mov a,#44h,’d’

lcall dwr

mov a,45h,’e’

lcall dwr

mov a,4eh,’n’

lcall dwr

mov a,49h,’i’

lcall dwr

mov a,45h,’e’

lcall dwr

mov a,44h,’d’

lcall dwr

lcall delay2

lcall delay2

lcall delay2

lcall delay2

lcall delay2

mov a,#01h

lcall cmd




                  27
                             Rfid based security access control system

jmp ready

Mr som: mova,#80h

        lcall cmd

            setb p1.1

        mov a,#’m’

            lcall dwr

        mov a,# ‘r’

        lcall dwr

        mov a,# ‘ ‘

        lcall dwr

       mov a,# ’S’

       lcall dwr

       mov a,# ‘O’

       lcall dwr

       mov a,# ‘M’

       lcall dwr

       mov a,# ‘A’

       lcall dwr

       mov a,#’S’

       lcall dwr

       mov a,# “U’

       lcall dwr

       mov a,# ‘N’

       l call dwr

        mov a,# ‘D’




                        28
                                Rfid based security access control system

        l call dwr

            mov a,# ‘A’

        lcall dwr

        mov a,#’R’

        lcall dwr

        mov a,#’A’

            lcall dwr

        mov a,#’N’

        lcall dwr

            lcall delay1

            lcall delay1

            lcall delay1

            lcall delay1

        lcall delay1

        lcall delay1

        lcall deiay1

        ret

Mr taj:mov a,#80h

Lcall cmd

Setb p1.1

Mov a,# ’M’

Lcall dwr

mov a,# ’r’

lcall dwr

mov a,# ’ ’




                           29
                            Rfid based security access control system

lcall dwr

mov a,# ’T’

lcall dwr

mov a,# ‘H’

lcall dwr

mova,# ‘A’

lcall dwr

mov a,# ‘D’

lcall dwr

mov a,# ‘D’

lcall dwr

mov a,#’I’

lcall dwr

mov a,#’N’

lcall dwr

lcall delay1

lcall delay1

lcall delay1

lcall delay1

lcall delay1

lcall delay1

ret

cmd,mov dptr,#0f100h

clr p1.6

movx @dptr,a




                       30
                             Rfid based security access control system

lcall delay

setb p1.6

ret

dwr: mov dptr,#0f100h

movx @dptr,a

lcall delay 2

ret

delay: clr psw.4

mov r4,#10h

dly1 :mov r3,#0ffh

dly2:dec r3

cjne r3,#00h,dly2

dec r4

cjne r4,#00h dly1

ret

delay1:mov r5,#03h

dloop3:mov r4,#0ffh

dloop2:mov r3,#0ffh

dloop1:dec r3

cjne r3,#00h,dloop1

dec r4

cjne r4,#00h,dloop2

dec r5

cjne r5,#00h,dloop3

ret




                        31
                                                            Rfid based security access control system

delay2:mov r4,#09h

dloop5:mov r3,#0ffh

dloop4:dec r3

cjne r3,#00h,dloop4

dec r4

cjne r4,#00h,dloop5

ret

delay#:mov r4,#30h

dloop7:mov r3,#0ffh

dloop6:dec r3

cjne r3,#00h,dloop6

dec r4

cjne r4,#00h,dloop7

ret

end




Result and discussion



    The circuit for ‘security access control system using RFID ‘ as per the circuit has been set up .
Circuit diagram and the PCB layout were developed in the ORCAD software. This has been successful-
ly interfaced with the microcontroller.




                                                32
                                                           Rfid based security access control system

    The user has to show the RFID tags. The program in the microcontroller analyses whether he is
our HOD, PROJECT guide or stranger. If he is a stranger he is denied access.

When the access is granted, corresponding message is displayed and the door is opened. The RFID
reader will detect the RFID tag efficiently at a maximum distance of 30 cm.




Conclusion and future scope



     Our project “security access control system using RFID ‘ has been successfully completed and
it prove to be a prime runner in the existing security control systems . The reader detects the tag




                                                33
                                                               Rfid based security access control system

and it is successfully operating the door. The entire system can be fixed in front which has to be ac-
cessed.

    The system can be easily converted into a toll collecting system. E-Z passes uses this technology
to collect tolls in toll gates which deduct the toll amount from the RFID enabled credit card and
allows you to pass the toll gate. All these are done in a span of few seconds. This technology can
also be used in petrol pumps where car entering is scanned to check pumps where car enter-
ing is scanned to check whether it is RFID enabled and if it is the gate opens tills in the petrol
and deducts the amount from the card thee customer is having . major developing are happen-
ing particularly in the Europe where short rage transponder magnetic coupling ) are being in-
cluded I motor cars keys , allowing the on board management computer to the verify the au-
thenticity of the key to try to reduce motor car theft .

    By counting the number of entries which the system has been accessed ,the number of the
people entered can be calculated . This facility will be helpful in high security areas such as in the
press meet ,board meetings et c. This system can also be used as an attendance counting mecha-
nism. This will be most useful in offices. Most of the MNC uses RFID door locking in the offices. Here it
not only provides as a security mechanism but also as an attendance counter.



\chapter{PCB Fabrication}

\section{The PCB Design}



    Design of printed circuit board (PCB) can be considered as the last step in electronic circuit design
as well as the first step in production of PCB. It plays important role in the performance and reliability
of electronic circuits, the productivity of the PCB’s its assembling, and its serviceability depends on
design. All these factors get reflected in a piece of electronic equipment. It is clear that task of PCB
design is not very simple or always straightforward. The schematic is follower by layout generation.
Layout design is the stage where engineering capacity combined with creativity is the governing in-
puts.



\section{Electronic Design Automation Tools}



    Most product testing is being done with the help of computer programs. The term Electronic De-
sign Automation (EDA) is being used to describe the use of these tools. With the help of advanced
powerful computing systems and interactive software tools and development of electronic circuits
has undergone automation. Thus the software and hardware tools, which enables this automation in-




                                                  34
                                                               Rfid based security access control system

cludes PCB designing, IC design, circuit simulation etc. These tools help us in such a way that we can
draw the circuit; test the functioning of the circuit in response to test inputs in simulation software.



After successfully simulation we can get the PCB artwork done by replacing the routing software. The
design automation tool used here is EAGLE (Easily Applicable Graphics Layout Editor).



\section{PCB Design Procedures}



    The PCB designing procedure consists of following steps:

\begin{description}

\item[Drawing the circuit schematic]



   Drawing of circuit is done through EAGLE schematic. It includes many libraries with thousands of
component symbols. We can select the required symbol from the library and place if in the schematic
page. After placing the component symbols, we can complete the interconnection using wire or bus
control.



The next step is to assign part reference. Each component has to be assigned footprint or PCB pat-
tern name. The footprint gives the actual size physical, representation of components on the PCB
artwork. The component symbol and foot symbol should correspond in all respects.




\item[Design Rule check and net list creation]



    After the circuit schematic is completed with all required information such as part reference and
footprints, the design rule check can be used for checking errors in the design. It will check for dupli-
cate symbols, overlapped lines and dangling lines.




                                                  35
                                                              Rfid based security access control system

After the schematic design file passes the DRC check, it is processed by a program called an electric
rule checker (ERC) that checks for wiring errors. The final operation to be done before starting PCB
artwork is the net list creation.

    A net list creation of the components and interconnection along with other information such as
foot prints, track width, etc. A net list software or tool can take the circuit schematic as input and
generate net list. The net list can be used as an information source for the remaining stages.

\item[Creating the PCB artwork ]



    In automatic design, the net list obtained from the previous stages is used for getting the re-
quired foot print and interconnections. The software used for the PCB artwork design in the EAGLE
layout.




\item[PCB Fabrication]



The PCB consists of insulating base material on which conductors are attached by photographic
method or screen-printing method or manual method. The PCB with conductors only one side of the
base material is called single sided PCB and with conductors on both sides called double-sided PCB.
The insulating material gives mechanical rigidity and electrical isolation for the printed conductor. The
following steps are involved in the fabrication of the PCB.

\begin{enumerate}

\item Preparation of the layout.

\item Transfer the layout in to copper.

\item Etching to remove the copper from the copper clad wherever it is not

    required.

\end{enumerate}




                                                  36
                                                              Rfid based security access control system

\end{description}

First step in the drawing of the layout on the copper clad. The layout is coated with a material such as
paints, to retain the copper lines on the PCB. After painting the clad sheet is dipped in the solution of
ferric chloride. After some time it can be seen that uncoated copper is etched out. The reaction, tak-
ing place can be expressed by following equation.

\\FeCl3 + Cu    ((CuCl3 + Fe)).

\\There are some conditions for layout making. They are the following:

The negative track must be larger than the positive track.

Positive track should be upper side of the PCB and the negative track is at the lower side of the PCB.

Positive and negative track should not cross.

Tinning angle of conductors should not be less than 90°.

Layout should be developing in the direction of the signal flow as far as possible.

Larger components should be placed first and then decreasing order of the size.

Components required input and output connection should near the end connections.

While preparing layout draw the conductor lines only on grid lines.

Spacing between conductors must be confirmed.

In the case of transformer, connects it on the out side of the PCB and connect the leads on the PCB.




                                                  37

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:135
posted:12/13/2011
language:English
pages:37