New Project Report - Copy

CHAPTER 1

INTRODUCTION

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1.1 BLOCK DIAGRAM:

SYSTEM AT ONE BUS STOP

Fig 1.1 Block Diagram of bus stop automation

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RF ID READER MICROCONTOLLER DISPLAY

POWER SUPPLY UNIT

SYSTEM AT ANOTHER BUS STOP

Connection with Bus Stop

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RF ID READER MICROCONTOLLER

DISPLAY

POWER SUPPLY UNIT

1.2 Block Diagram Description

Microcontroller Block:It is a low power, high-performance 8-bit microcomputer with

8K bytes of Flash Programmable and Erasable Read Only Memory ROM). The device is

manufactured using Atmel’s high-density nonvolatile memory technology, instruction set

and pin out. 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, it provides a highly flexible and cost effective

solution so many embedded control applications.

RFID Block: RFID is a dedicated short-range communication technology. The term

RFID used to describe various technologies that use radio waves to identify people or

objects automatically. RFID technology is similar to the bar code identification systems;it

consists of reader and tag. RFID tags support a larger set of unique IDs than bar codes.

Real Time Clock (RTC): The DS1307 serial real-time clock (RTC) is a low power, full

binary coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and

data are transferred serially through the bidirectional bus. The clock/calendar provides

seconds, minutes, hours, day, date, month, and year information.

Display Block: In this project, we are using 16X2 LCD displays, for displaying current

date and bus status. The liquid-crystal display has the distinct advantage of having low

power consumption than the LED.

Power Supply Block: Initial stage of every electronic circuit is power supply system that

provides required power to drive the whole system. The specification of power supply

depends on the power requirement and this requirement is determined by its rating. For

our project we require + 5 Volt. 5Volts given to micro-controller board, and other

devices.

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CHAPTER 2

METHODOLOGY

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2.1Main required components for making RFID based BUS STOP AUTOMATION

A] Hardware part:-

1. Power Supply Unit

2. Microcontroller AT89S52

3. Voltage regulator LM7805

4. Timer IC DS1307

5. RFID reader

6. LCD Display

7. Pull-up resistors

8. RTC (Real time clock)

9. Dome keypad

10. Passive Cards

B] Software used:

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i) Embedded C – For programming

ii) Express SCH

Express SCH software is used for Circuit designing.

Steps for Designing:

1. Begin a new schematic by running Express SCH. You can launch Express SCH from

your desktop by clicking on the icon.

2. Select New from the File menu. Then start designing a schematic diagram.

3. Take component from Components and Symbols manager as per required and it by

using wire.

4. In this way we can make schematic diagram.

EXPRESS SCH

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Fig 2.1 Express SCH

2.2 HARDWARE PARTS

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2.3 POWER SUPPLY UNIT

Power supply block consists of following units:

• Step down transformer

• Full wave rectifier circuit

• Input filter

• Voltage regulators

• Output filter

• Indicator unit

INTRODUCTION

There are many types of power supply. Most are designed to convert high voltage AC

mains electricity to a suitable low voltage supply for electronic circuits and other devices.

A power supply can by broken down into a series of blocks, each of which performs a

particular function. For example a 5V regulated supply can be shown as below

Fig 2.2: Block Diagram of a Regulated Power Supply System

Similarly, 12V regulated supply can also be produced by suitable selection of the

individual elements. Each of the blocks is described in detail below and the power

supplies made from these blocks are described below with a circuit diagram and a graph

of their output.

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Transformer

A transformer steps down high voltage AC mains to low voltage AC. Here we are using a

center-tap transformer whose output will be sinusoidal with 36volts peak to peak value.

Fig 2.3: Output Waveform of transformer

The low voltage AC output is suitable for lamps, heaters and special AC motors. It is not

suitable for electronic circuits unless they include a rectifier and a smoothing capacitor.

The transformer output is given to the rectifier circuit.

RECTIFIER

A rectifier converts AC to DC, but the DC output is varying. There are several types of

rectifiers; here we use a full wave rectifier. The full wave rectifier is a circuit, which

converts an ac voltage to dc voltage using both half cycles of the input ac voltage. The

circuit has two diodes connected to form a FWR. The load resistance is connected

between the other two ends.Now the output of the rectifier is shown in Figure 4.3 below.

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Fig 2.4 Output of rectifier

Smoothing or filtering

The smoothing block smoothes the DC from varying greatly to a small ripple and the

ripple voltage is defined as the deviation of the load voltage from its DC value.

Smoothing is also named as filtering.Filtering is frequently effected by shunting the load

with a capacitor. The action of this system depends on the fact that the capacitor

storesenergy during the conduction period and delivers this energy to the loads during the

no conducting period. In this way, the time during which the current passes through the

load is prolonging Ted, and the ripple is considerably decreased.

The action of the capacitor is shown with the help of waveform.

Figure 2.5 Smoothing action of capacitor

REGULATOR

Regulator eliminates ripple by setting DC output to a fixed voltage. Voltage regulator ICs

are available with fixed (typically 5V, 12V and 15V) or variable output voltages.

Negative voltage regulators are also available. Many of the fixed voltage regulator ICs

has 3 leads (input, output and high impedance). They include a hole for attaching a heat

sink if necessary. Zener diode is an example of fixed regulator which is shown here.

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Fig.4.9 Regulator IC

2.4RFID READER

RFID READER is the main component of our project. Main function of RFID reader is

to provide excitation voltage to the RFID tag and get unique no. From it the unique no

from the RFID reader is then transfer to the microcontroller through the serial

communication or serial port. Microcontroller then compares the received no from the

reader with its internal memory. If that no is matches with the stored no then it sends that

data to another bus stop.Each transponder tag contains a unique identifier that read by the

RFID Card Reader and transmitted to the host via a simple serial interface.

Radio Frequency Identification (RFID) Card Readers provide a low-cost solution to read

passive RFID transponder tags up to 7 cm away. The RFID card reader read the RFID tag

in range and outputs unique identification code of the tag at baud rate of 9600. The data

from RFID reader can be interfaced to be read by microcontroller or PC.

2.4.1 Features

• Low-cost method for reading passive RFID transponder tags

• 9600 bps serial interface at 5V TTL level for direct interface to microcontrollers

• LED indicate valid RFID Tag detection

• Range up to 7 cm for 125 KHz RFID Cards

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Specification

Parameter Value

Input Voltage5V DC regulated

Output Data Speed9600 BPS

8 Bit Data/No-Parity/1 Stop Bit

Output Data Level 5V TTL level

Detection Range 7 cm contact-less

Valid Tag in Range Indicated by Buzzer and LED

2.4.2Communication

When the RFID Card Reader is active and a valid RFID transponder tag placed within

range of the activated reader, the unique ID transmitted as a 12-byte printable ASCII

string serially to the host in the following format:

Start Byte

(0x0A) Unique ID

Digit 1 Unique ID

Digit 2 Unique ID

Digit 3 Unique ID

Digit 4 Unique ID

Digit 5 Unique ID

Digit 6 Unique ID

Digit 7 Unique ID

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Digit 8 Unique ID

Digit 9 Unique ID

Digit 10 Stop Byte

The start byte and stop byte are used to easily identify that a correct string has been

received from the reader. The middle ten bytes are the actual tag's unique ID.For

example, for a tag with a valid ID of 0F0184F07A, the following ASCII data would be

sent 0F0184F07A

Same data in HEX bytes can be interpreted as:

0x0A, 0x30, 0x46, 0x30, 0x31, 0x38, 0x34, 0x46, 0x30, 0x37, 0x41, 0x0D

All communication is 8 data bits, no parity, 1 stop bit, and least significant bit first. The

baud rate is configured for 9600 bps, a standard communications speed supported by

most any microprocessor or PC, and cannot be changed. The RFID Card Reader initiates

all communication. This allows easy access to the serial data stream from any

programming language that can open a COM port.

2.4.3 Using RFID Reader

When powered on the RFID reader will activate a RF field waiting for a tag to come into

its range. Once tag is detected, its unique ID number is read and data is sent via serial

interface. The face of the RFID tag should be held parallel to the front of the antenna

(where the majority of RF energy is focused). Only one transponder tag should be held up

to the antenna at any time. The use of multiple tags at one time will cause tag collisions

and confuse the reader. The tags available with us have a read distance of approximately

7 cm. Actual distance may vary slightly depending on the size of the transponder tag and

environmental conditions of the application.

2.4.4 RFID Technology Overview

Radio Frequency Identification (RFID) is a generic term for non-contacting technologies

that use radio waves to automatically identify people or objects. There are several

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methods of identification, but the most common is to store a unique serial number that

identifies a person or object on a microchip that is attached to an antenna. The combined

antenna and microchip are called an "RFID transponder" or "RFID tag" and work in

combination with an "RFID reader" (sometimes called an "RFID interrogator").

There are two major types of tag technologies. "Passive tags" are tags that do not contain

their own power source or transmitter. When radio waves from the reader reach the

chip’s antenna, the energy is converted by the antenna into electricity that can power up

the microchip in the tag (known as "parasitic power"). The tag is then able to send back

any information stored on the tag by reflecting the electromagnetic waves as described

above. "Active tags" have their own power source and transmitter.

2.5THE SERIAL PORT

In computing, a serial port is a serial communication physical interface through which

information transfers in or out one bit at a time (contrast parallel port). Throughout most

of the history of personal computers, data transfer through serial ports connected the

computer to devices such as terminals and various peripherals.Modern computers without

serial ports may require serial-to-USB converters to allow compatibility with RS 232

serial devices. Serial ports are still used in applications such as industrial automation

systems, scientific instruments, shop till systems and some industrial and consumer

products. Server computers may use a serial port as a control console for diagnostics.

Network equipment (such as routers and switches) often use serial console for

configuration. Serial ports are still used in these areas as they are simple, cheap and their

console functions are highly standardized and widespread. A serial port requires very

little supporting software from the host system.

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2.6AT89S52- 8 bit Microcontroller with 8K Bytes In-System Programmable Flash

Description

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with

8KBytes of in-system programmable Flash memory. The device is manufactured

usingAtmel’s high-density nonvolatile memory technology and is compatible with the

industry- standard 80C51 instruction set and pin out. 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 in-system programmable

flash ona monolithic chip, the Atmel AT89S52 is a powerful microcontroller which

provides a highly-flexible and cost-effective solution to many embedded control

applications. The AT89S52 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 AT89S52 is designed with static logic for operation down to zero frequency

and supports two software selectable power saving modes.

Pin Configurations

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Fig2.7 Pin configuration of AT89S52

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Fig2.8 Architecture of AT89S52

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Fig2.9 Pin Diagram of AT89S52

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Pin Description

VCC- Supply voltage.

GND- Ground.

Port 0- Port 0 is an 8-bit open drain bidirectional I/O port. When 1’sare written to port 0

pins, the pins can be used as high impedance inputs. Port 0 can also be configured to be

the multiplexed low order address/data bus during accesses to external program and data

memory. External pull-ups are required during program verification.

Port 1-Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are

pulled high by the internal pull-ups and can be used as inputs. In addition, P1.0 and P1.1

can be configured to be the timer/counter 2 external count input (P1.0/T2) and the

timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the following table.

Fig 2.10 Pin configuration of Port 1

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. When 1s are written to Port

2 pins, they are pulled high by the internal pull-ups and can be used as inputs. Port 2

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emits the high-order address byte during fetches from external program memory and

during accesses to external data memory that uses 16-bit addresses (MOVX @DPTR). In

this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to

external data memory that uses 8-bit addresses (MOVX @ RI), Port 2emits the contents

of the P2 Special Function Register.

Port 3

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. When 1s are written to Port

3 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs,

Port 3 pins that are externally being pulled low will source current (IIL) because of the

pull-ups. Port 3 also serves the functions of various special features of the AT89S52, as

shown in the following table. Port 3 also receives some control signals for Flash

programming and verification.

Fig 2.11 Pin configuration of port 3

RST Reset input. A high on this pin for two machine cycles while the oscillator is

running resets the device. This pin drives high for 96 oscillator periods after the

Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to

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disable this feature. In the default state of bit DISRTO, the RESET HIGH out feature is

enabled.

ALE/PROG Address Latch Enable (ALE) is an 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 constant

rate of1/6 the oscillator frequency and may be used for external timing or clocking

purposes. Note, however, that one

Preprogram Store Enable (PSEN) is the read strobe to external program memory.When

the AT89S52 is executing code from external program memory, PSEN is activated twice

each machine cycle, except that two PSEN activations are skipped duringeach 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 external program memory locations starting at 0000H up to

FFFFH.EA should be strapped to VCC for internal program executions. This pin also

receives the 12-volt programming enable voltage(VPP) during Flash programming.

XTAL1- Input to the inverting oscillator amplifier and input to theinternal clock

operating circuit.

XTAL2- Output from the inverting oscillator amplifier.

2.7 DS1307 - Serial, I2C REAL TIME CLOCK

GENERAL DESCRIPTION

The DS1307 serial real-time clock (RTC) is a low power, full binary-coded decimal

(BCD) clock/calendar plus 56 bytes of RAM. Address and data are transferred serially

through an I2C, bidirectional bus. The clock/calendar provides seconds, minutes, hours,

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day, date, month, and year information. The end of the month date is automatically

adjusted for months with fewer than 31 days, including corrections for leap year. The

clock operates in either the 24-hour or 12-hour format with AM/PM indicator.

FEATURES

• Real-Time Clock (RTC) Counts Seconds, Minutes, Hours, Date of the Month, Month,

and Day of the week and Year with Leap-Year Compensation Valid Up to 2100

• 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes

• I2C Serial Interface

• Programmable Square-Wave Output Signal

• Automatic Power-Fail Detect and Switch Circuitry

• Consumes Less than 500nA in Battery-Backup Mode with Oscillator Running

• Optional Industrial Temperature Range: -40°C to +85°C

• Available in 8-Pin Plastic DIP or SO

• Underwriters Laboratories (UL) Recognized

TYPICAL OPERATING CIRCUIT

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Fig 2.12 Real time clock operating circuit

2.8 LIQUID CRYSTAL DISPLAY

LCD MODULE

The HD44780U dot-matrix liquid crystal display controller and driver LSI displays. It

can be configured to drive a dot-matrix liquid crystal display under the control 8-bit

microprocessor. Since all the functions such as display RAM, character generator, and

liquid crystal driver, required for driving a dot-matrix liquid crystal display are internally

provided on one chip, a minimal system can be interfaced with this controller/driver. In

the recent years LCD, is finding in daily use replacing LED’s which may be Single,

Seven Segment or Multi Segment LED’s Because of Declining Pricing of LCD and

ability to display numbers, characters and graphics. Another advantage of LCD is that,

Incorporation of refreshing controller in to LCD for relieving the CPU of the task of

refreshing LCD.

A 16x2 LCD means it can display 16 characters per line and there are 2 such lines. In this

LCD, each character is displayed in 5x7-pixel matrix. This LCD has two registers,

namely, Command and Data.The command register stores the command instructions

given to the LCD. A command is an instruction given to LCD to do a predefined task like

initializing it, clearing its screen, setting the cursor position, controlling display etc. The

data register stores the data to be displayed on the LCD. The data is the ASCII value of

the character to be displayed on the LCD.

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Fig 2.13 LCD in 4 bit Module

2.9 SOFTWARE PART

2.9.1 INTRODUCTION TO EMBEDDED C

Looking around, we find ourselves to be surrounded by various types of embedded

systems. Be it a digital camera or a mobile phone or a washing machine, all of them has

some kind of processor functioning inside it. Associated with each processor is the

embedded software. If hardware forms the body of an embedded system, embedded

processor acts as the brain, and embedded software forms its soul. It is the embedded

software which primarily governs the functioning of embedded systems.

During infancy years of microprocessor based systems, programs were developed using

assemblers and fused into the EPROMs. There used to be no mechanism to find what the

program was doing. LEDs, switches, etc. were used to check correct execution of the

program. Some ‘very fortunate’ developers had In-circuit Simulators (ICEs), but they

were too costly and were not quite reliable as well.

As time progressed, use of microprocessor-specific assembly-only as the programming

language reduced and embedded systems moved onto C as the embedded programming

language of choice. C is the most widely used programming language for embedded

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processors/controllers. Assembly is also used but mainly to implement those portions of

the code where very high timing accuracy, code size efficiency, etc. are prime

requirements.

Advantages

It is small and reasonably simpler to learn, understand, program and debug.

Compared to assembly language, C Code written is more reliable and scalable, more

portable between different platforms.

C Compilers are available for almost all embedded devices in use today, and there is

a large pool of experienced C programmers.

Unlike assembly, C has advantage of processor-independence and is not specific to

any particular microprocessor/ microcontroller or any system. This makes it

convenient for a user to develop programs that can run on most of the systems.

As C combines functionality of assembly language and features of high level

languages, C is treated as a ‘middle-level computer language’ or ‘high level assembly

language’

It is fairly efficient

It supports access to I/O and provides ease of management of large embedded

projects.

2.9.2 PROGRAMMING

#include<at89c51ed2.h>

//#include<stdio.h>

//#define ALARM P3_6

#define I2C_DELAY 0x07

#define SEC 0x00

#define MIN 0x01

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#define HOUR 0x02

#define DATE 0x04

#define MONTH 0x05

#define YEAR 0x06

void save(unsigned int eeprom,unsigned int addr,unsigned int val);

int read_mem(unsigned int eeprom,unsigned int addr);

void display();

code unsigned char data1[52]={ ' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ','M','I','E','T','

','W','E','L','C','O','M','E',' ','Y','O','U',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};

code unsigned char data2[11]={'B','U','S',' ','N','O',':','1','1','1','1'};

code unsigned char data3[11]={'B','U','S',' ','N','O',':','2','2','2','2'};

code unsigned char data4[11]={'B','U','S',' ','N','O',':','3','3','3','3'};

code unsigned char data5[11]={'B','U','S',' ','N','O',':','4','4','4','4'};

code unsigned char data6[11]={'A','R','R','A','V','I','N','G','*','*'};

code unsigned char data7[15]={'N','A','G','P','U','R',' ','C','I','T','Y','*'};

code unsigned char data8[15]={'G','O','N','D','I','A',' ','C','I','T','Y','*'};

//code unsigned char data8[15]={'G','P','B','R','*',' ',' ',' ',' ',' ',' ',' '};

unsigned char distance[15]={68,73,83,84,65,78,67,69,32,32,48,48,48};

unsigned char distance1[15]={48,48,48,48,48,48,48,48,48,48,48,48,48};

idata date[15]={68,65,84,69,32,48,49,47,48,49,47,48,49};

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idata time[15]={84,73,77,69,32,48,48,58,48,49,58,48,49};

idata char smin,shour,sdate,smonth,syear,dat,hour,min,sec,month,year;

int sdst,x2;

void main(void);

void delay_ms1(unsigned int t);

void send(unsigned char k);

void int_fun();

//void ck_status();

unsigned int x1,cnt1,eepromid;

unsigned int cnt,cnt2;

int cvl;

char redata;

unsigned int dst,dst1,dst2,dst3;

void ms_delay(unsigned int t)

{

void decdate()

{

//unsigned char i;

sdate=sdate-1;

void incmin()

{

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//unsigned char i;

smin=smin+1;

}

void dechour()

{

//unsigned char i;

shour=shour-1;

if(shour<0)

{

shour=23;

}

else

{

shour=shour;

}

void save(unsigned int eeprom,unsigned int addr,unsigned int val)

{

unsigned int r,s;

r=val/256; //separate out 16bit data for loading

s=val%256; //devide by 256 to fit 8 bit data//

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//addr=addr;

EEPROM_set(eeprom,addr,r); //save on 1st(0x00) loc.of mem

ms_delay(120);

//disp_vl(11,x2);

addr++;

EEPROM_set(eeprom,addr,s);

//disp_vl(11,x2);

}

for(i=0;i<13;i++)

{

lcd_data(date[i]);

}

ms_delay(2000);

}

void set_year()

{

unsigned char j,l;

syear=DS1307_get(YEAR);

for(j=0;j<3;j++)

{

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//disp_para(4,19,20,syear);

dis_date(syear,11);

setd_dis();

}

for(l=0;l<250;l++)

{

for(j=0;j<1;j++)

{

//disp_para(4,19,20,syear);

dis_date(syear,11);

//display();

setd_dis();

}

ms_delay(20000);*/

switch(distance1[11])

}

if(P3_4==0)

{

dis1();

//dis1();

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P1_4=1;

}

if(P3_5==0)

{

dis2();

//dis2();

P1_5=1;

}

if(P3_6==0)

{

dis3();

//dis3();

P1_6=1;

}

if(P3_7==0)

{

dis4();

//dis4();

P1_7=1;

}

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}

for(i=0;i<12;i++)

{

lcd_data(data7[i]);

}

ms_delay(20000);

}

/*void run_mode()

{

//unsigned char l,m,n;

while(1)

{

display();

display();

//work();

//motor();

switch(distance1[11])

{

case 'C':

P2_0=0;

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P2_7=1;

distance1[11]=0;

break;

case 'D':

P2_1=0;

P2_6=1;

distance1[11]=0;

break;

case 'F':

P2_2=0;

P2_5=1;

distance1[11]=0;

break;

case '3':

P2_3=0;

P2_4=1;

distance1[11]=0;

break;

}

if(P2_4==0)

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{

dis1();

//dis1();

P2_3=1;

}

if(P2_5==0)

{

dis2();

//dis2();

P2_2=1;

}

if(P2_6==0)

{

dis3();

//dis3();

P2_1=1;

}

if(P2_7==0)

{

dis4();

//dis4();

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P2_0=1;

}

}

{

lcd_data(data1[i]);

}

ms_delay(5000);

}

//unsigned char i;

TCON=0x00;

PCON=0x00;

dst2=0;

/*TMOD=0x21;//for serial & interrupt function

SCON=0x50;

TH0=0x4B;//for 1 sec

TL0=0xFD;

TH1=0xFD;

IE=0x92;

TR0=1;

TR1=1;*/

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lcd_cmd(0x38);

disp_start();

2.10 CIRCUIT DIAGRAM

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Fig 2.14 Circuit diagram

CHAPTER 3

PCB DESIGNING AND PLANNING

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3.1 INTRODUCTION TO PCB ARTIST

Printed Circuit Boards Basics

PCB’s are the backbone of any electronic devices, and therefore knowledge of PCB

layout tools can be a vital skill. Both analog and digital circuits used in PCBs depending

on the application, and with different types of circuits, the designer must take into

account certain design considerations. More Advance circuits like RF circuits or Power

circuits take more thought in the layout and design because the circuit is more sensitive to

component placement and the lengths of the connections between them.

The process for PCB design is to first create a list of parts you will use in the circuit, and

then take the footprint of the component from libraries available. After taking footprint,

you have to connect that component by track. Then finally place all the components’ in

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this manner and connect them physically how you want them to be fabricated on the

board.

3.2 LAYOUT PLANNING:

The layout of PCB has to in co-operate all possible information and components on the

circuit board, as given in the circuit diagram. After that one can proceed to artwork

preparation.

LAYOUT SCALE:

Depending upon the accuracy in the layout artwork is done according to scale selected.

Scales selected may be 1:1, 2:1 or4:1 which is four times or sixteen times of the actual

PCB. The layout is best prepared using the same scale.

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3.3 LAYOUT PROCEDURE:

While preparing any layout of an electronic circuit the first rule is to be remembered is

not to start the designing of the layout unless and until an absolutely clear and is not

available. Another important note is to prepare a before a hand PCB layout from

component side. This minimizes any further complication. Among the larger ones are

placed first and the space in between is filled with smaller ones. All components are not

necessary if they have to be replaced.

• To take distance between terminal leads of each component.

• To take size of the components into consideration.

Smaller components like IC’s resistance etc. are placed in the center of the layout and

bigger component like electronic capacitor are placed in the outskirts. All components are

placed in such a manner that disordering is possible. This they help in fast testing of

circuit.

LAYOUT SKETCH:

The end product of layout designing is a pencil sketch on the copper clad sheet and

conductor draw in which is labeled as layout sketch which contain of reluctant

information for preparation of artwork.

ARTWORK PREPARATION:

The preparation of artwork is considered as the first step in preparation of PCB, different

procedure is available to prepare a good network. Some of them are listed below.

• Use of paint or marker for preparation of artwork.

• Use of black tape on transparent base toil.

• Use of PCB drifting aid.

• Screen-printing.

ETCHING

After the artwork is prepared on the circuit board, all excessive copper on the copper clad

sheet is to be removed, only copper tracks remaining on the copper clad. The copper clad

sheets are the once on etching tape of paint is applied.

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During the etching process it is understood that the process happen vertically however

practically, the etching action is always sideways.

ECHENTS

Among the etchants uses ferric chloride (Fecl3) is the most common etchants used

because of its hygroscopic non-volatile and good solubility with wafer. The following

reaction takes place during the etching process.

Fecl3 + Cu Fecl2 +cucl

Due to high corrosiveness of fecl3 etching is faster.

RINSING

After etching is done fecl2 contaminated surface should be cleaned. The usual practice

follows rinsing by wafer and cleaning by oxalic acid. A vigorous final wafer rinse has to

follow.

DRILLING

Drilling mechanical holes is also an important operation. Drilling is done by using drill

bits from 0.8mm to 2mm as per components, drilling can be done by using hand drill or

an electric drill. To compensate for the lamination a drill bit 0.04mm bigger than the

whole diameter is chosen.

SOLDERING

Soldering is the stage for completion of any circuit. It is the process in which the alloy of

tin and lead is heated of about 300 to melt and set itself around the components lead

surface.

There are two types of soldering techniques:

• Manual Soldering

• Wave Soldering

Manual soldering is the technique which is operated by us for soldering very few

components whereas wave soldering is used to solder mass number of components. Wave

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soldering is done by special machines.Care should be taken that flux or solder paste is

applied to surface where soldering to be done so as to quicken the process.

3.4 PCB LAYOUT

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Fig 2.16 PCB layout

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CHAPTER 4

FEATURES

It is a RFID Enabled & contactless system.

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RFID technology has following features

RFID tags don’t need to be positioned in a line of sight with the scanner.

RFID tags can be read at a faster rate; as approximately 40 RFID tags can be read

at the same time.

RFID tags can work within much greater distances; information can be read from

a tag at up to 300 ft.

RFID tags are read/write devices.

RFID contain high levels of security; data can be encrypted, password protected

or set to include a ‘kill’ feature to remove data permanently.

RFID tags carry large data capabilities such as product maintenance, shipping

histories and expiry dates; which can all be programmed to the tag.

Once these are set up; it can be run with minimal human participation.

RFID tags are more reusable and rugged as they are protected by a plastic cover.

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CHAPTER 5

CONCLUSION & FUTURE EXPANSION

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CONCLUSION

Thus we have studied RFID based bus stop automation. We got that this is very

useful in present and future demand. It is simple to operate & can be installed

conveniently. In this project we can control the data which is sending from

transmitter to receiver by using microcontroller AT89S52.

FUTURE EXPANSION

Using GSM, this project can be made wireless.

Generalized version of this project is also possible with some variations in

programming.

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REFRENCES

www.8051microcontroller.com

www.wikipedia.org

RFID reader

RFID tags & contactless smart card technology

Smartcard alliance

www.alldatasheets.in

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APPENDIX

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52

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