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A Project Report on

ROLLING DISPLAY USING 89C51

Submitted by

Rahul S Thombre

Poonam B Wagh

Addala Shashank V Rao

In fulfilment for the award of

Bachelor of Engineering

( Electronics and Tele-communication )North Maharashtra University,

Jalgaon (M.S).

Department Of Electronics and Telecommunication

Government College of Engineering ,Jalgaon.

(2010-2011)

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CERTIFICATE

This to certify that, the dissertation ROLLING DISPLAY USING 89C51

submitted by

Jayashree N. Sonar

Neha P. Patil

Rupali D. Rane

Is a bonafide work completed under my supervision and guidance in partial fulfillment

for the award of Bachelor of Engineering (Electronics and Telecommunication) Degree of North

Maharashtra university, Jalgaon.

Place: Jalgaon

Date:

Mrs. Y.D.Kapse Mr. G. K. Andurkar

(Project Guide) (Head of Department)

Electronics and Telecommunication Electronics and Telecommunication

Dr.D.S.Chaudhari

Principal

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SYNOPSIS

Gas leakage in any area such as domestic, industrial etc. creates

hazardous problems .The gas leakage can form a gas clouds and any kind of spark

generated in this cloud will make explosion .This explosion can cause much of

damages to the industry .Suppose the industry is located in the city or area having

crowded population then it is important to inform people about gas leakage.so that

the people will take care that no spark are generated in that area.

To avoid the above stated problem we have develop the project.This is the gas leakage detection in remote areas .Where the presence of human

beings is rare such as a factory or any gas pipelines.The gas leakage can be

detected by smell of gas,but for detection of gas in industrial areas a gas sensor is

used .This is an inexpensive permanently installed system capable of detecting

even the minutest of leaks in gas pipelines.

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INTRODUCTION

1.1 PROBLEM STATEMENT

Gas leakage in area such as domestic industrial and etc. creates hazardous

problems .The gas leakage can form a gas clouds and any kind of spark generated

in this clouds will make explosion. This explosion can cause much of damages to

the industry .Suppose the industry is located in the city or area having crowded

population then it is important to inform about gas leakage. So that the people will

take care that no spark are generated in that area .

1.2 SOLUTION

To avoid the above stated problem we have developed project .This is the gas

leakage detection in remote area ,where the presence of human being is rare such

as factory or any gas pipelines. The gas leakage can be detected by smell of gas.

But for detection of gas in industrial areas a sensor is used. This is an inexpensive,

permanently installed system capable of detecting even a minutest of leaks in gas

pipelines.

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HISTORY

In order to detect gas leaks with trasitional methods,The gas itself must either

be in close proximity to the detector or within a pre-defined area.Outdoor

environmental condition such as changing wind direction and quick dispersion of

potential gas cloud, which can be found e.g,. on an offshore platform can result in

undetected gas leaks, leading to extremely dangerous situations.

METHODS USED TO FIND AND IDENTIFY POINTS OF GAS LEAKS IN A

GAS PIPEING DISTRIBUTION SYSTEM OR AT A GAS APPLIANCE

1. Gas odors observed during gas piping inspection

2. Soap solution bubble tests for gas leaks : a solution of soapy water is

the most common method used to test for gas leaks .

3. Soap solution is applied at every piping joints or connection and the

technician watches the soaped connection to see if soap bubbles are formed.

Experts warn that this method requires some experience and care. e.g. a large gas

leak may blow away the solution without forming a soap bubble, or bubbles may

be forming a location which is physically hard to see.

4. Soap solution is applied along gas piping to lengths of piping to test for

pinholes mechanical damage if no leaks are found at threaded or flared

connectors but when gas leaks are evident on the system.

5. Gas leaks at gas valves: We very often find very small gas leaks at the

seamed sides of some gas valves such as those commonly found on gas -fired

domestic water heaters. These leaks can be so miniscule that they do not show

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during a bubble test, and they are often present even on new valves. This may be

a source of some disagreement between a home inspector, building owner and gas

service technician.

LITERATURE SURVEY:

In order to detect gas leaks with traditional methods, the gas itself must

either be in close proximity to the detector or within a pre-defined area. Outdoor

environmental condition such as changing wind directions and quick dispersion of

a potential gas clouds .Which can be found e.g. on a offshore platform, can result

in undetected gas leaks, leading to extremely dangerous situations.

Causes of Leakages:

There are many causes which contributes to the leakage problems in

pipeline system.

a) Corrosion:

Corrosion is not only contributing to the leakage problem it also affect quality of

gas being transmitted. Corrosion can occur inside or outside a pipe and causes a

pipe to become weaker in supporting the outer force exerted on it. Corrosion

which happens outside the pipe is mainly due to the environmental effect, while

gas quality and corrosion protection layer are the factors affecting corrosion

happening inside the pipe.

b) Material Defect:

Material of the pipeline used may not comply with the standard requirement. Thismeans that it may not be able to sustain the designed gas pressure and designed

traffic load so it stands a high potential to get burst and causes leakages problem.

c) Faulty Installations:

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Every pipe needs to be installed properly so that they can take up gas pressure and

traffic load designed. Poor workmanship on the pipes installation will greatly

reduce the capability of pipes to take up load exerted on it and eventually causes

leakage problem.

d) Excessive gas pressure:

Excessive gas resulting pipes with small thickness to be easily burst and causes

leakage problem .

e) Old & poorly constructed pipelines this is due to long term usage of

pipelines which is no longer sufficient in providing its service to gas supply. The

project relates to a method and system for detecting leaks from gas pipelines or

tankers .Gas pipeline leak detection can be sensed by smell (if an odourous

additive is present),detection by smell requires the presence of a person. It is

therefore an object of present invention to provide an inexpensive, permanently

installed system, capable of detecting even the minutest of leaks in gas

pipelines .A further object is to provide a method for detecting leaks from holes in

pressurized gas pipelines an indicating the vicinity of such leak..

Future Development:

1. As future point of view we can visualize system.

2. We can pinpoint the exact location of gas leakage .

3. Also by using BPA laser technology we can prevent environment from

Greenhouse gas.

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BLOCK DIAGRAM

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BLOCK DIAGRAM OPERATION

Figure shows basic Block Diagram ofGas and smoke detection and SMS

alert system. In this project there are following blocks .

1) Gas sensor

2) Smoke sensor

3) Micro controller

4) Display

5) Buzzer

6) Crystal and oscillator circuit

7) Regulated power supply

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1. Gas Sensor

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Gas Sensor Specification:-

Parameter Value Unit

Target Gas iso-butane, Propane, LPG

Detection Range 100 to 10000 ppm (part per millions)

Calibrated Gas 1000ppm iso-butane

Sensitivity Rin air / Rin typical gas5

Sensing Resistance 40 to 400K in air Ohms

Response Time 10s Seconds

Resume Time 30s Seconds

Heating Resistance 313 Ohms

Heating Current 180mA mA

Heater Voltage 5V0.2V Volts

Heating Consumption 900mW mW

Circuit Voltage 15V Volts

The gas leakage is out put is zero to one, which is detected by directly to

microcontroller 89C52.

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2.Smoke sensor

When smoke is raises near ceiling and ventilation of the room. To detect

the smoke, we use smoke detection sensor. When smoke passes through infrared

trins-receiver sensor conductivity between them. Ir receiver is detected change

pulse (zero to one). This pulse is sensed by micro controller unit directly.

3. Micro controller

This is the heart of our project so we select micro controller IC 89C52, due to

its number of advantages over other micro controller and microprocessor such as

inbuilt 4K electrical erasable programmable memory, 128 byte of RAM, four

external and three internal interrupts source, inbuilt two 16 bit timer and it is full

software and hardware compatible with industrial stander MCS51 family. The

software for this project is stored in its EEPROM and sensor; output devices are

connected to its input and output port.

we select 89C52 because of following advantages.

Computable with industrial most popular family MCS51 product

4K Bytes of In-System Reprogram able Downloadable Flash Memory

Endurance: 1,000 Write/Erase Cycles

4K Bytes EEPROM

Endurance: 100,000 Write/Erase Cycles

4V to 6V Operating Range

Fully Static Operation: 0 Hz to 24 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Nine Interrupt Sources

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Programmable UART Serial Channel

SPI Serial Interface

Low-power Idle and Power-down Modes

Interrupt Recovery from Power-down Programmable Watchdog Timer

Dual Data Pointer

4. Mobile decoder ( modem)

In our project we use mobile modem this mobile modem send SMS of daily

meter reading to pre define mobile number

5.LCD display

A Liquid Crystal Display is a thin, flat display device made up of any

number of colour or monochrome pixels arrayed in front of a light source or

reflector.It is prized by engineers because it uses very small amount of electric

power, and is therefore suitable for use in battery-powered electronic devices.

A very popular standard exist which allows us to communicate with the

vast majority of LCDs regardless of their manufacturers. The standard is referred

to as HD44780U, which refers to the controller chip which receives data from an

external source (in this case, the 8051 ) and communicates directly with the LCD.

The 44780 standard requires 3 control lines as well as either 4 or 8 I/O

lines for data bus.The user may select whether the LCD is to operate with a 4 bit

data bus. If a 4 bit data bus is used the LCD will require a total of 7 data lines (3

control lines plus the 4 lines for the data bus). If an 8- bit data bus is used the

LCD will require a total of 11 data lines (3 control lines plus the 8 lines for the

data bus).

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In our project to show power, we use 16x2 LCD alphanumeric display

with backlight. The advantages of this are that we write 32 characters on it and

due to backlight we can see it from long distance also. This display has 8 data line

and three control line through which micro controller write character on it.

6. Buzzer Unit

+ 6V dc buzzer is used for audio indication of smoke or gas leakage of

system. When gas leakage or smoke is detected, this unit produces sound to give

audio indication to nearby peoples to aware them about system.

7. Crystal & Reset Circuit

12MHz quartz ceramic crystal is connected between pin XTAL1, and

XTAL2 of micro controller to produce machine cycle for fetch and execution of

instruction. And at pin 9 RST pins we connect R.C n/w to provide reset pulse

when power is turn on so that programmed execution start from memory location

0000H.

8. Power Supply

For our all IC we require 5 v d.c. Supply, which can be generated by step

down transformer, full wave bridge rectifier, and filter condenser and voltage

regulator IC 7805.

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CIRCUIT DIAGRAM

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CIRCUIT OPERATION

Figure shows complete circuit Diagram of our project Gas and smoke

detection and SMS alert system, in this project we can monitor leakage of Gas

and detection of smoke for that purpose we use two type of sensor

1) Gas leakage 2) smoke detector.

Combustible Gas Sensor-

Used in gas leakage detecting equipments for detecting of LPG, iso-butane,

propane, LNG combustible gases. The sensor does not get trigger with the noise

of alcohol, cooking fumes and cigarette smoke.

The gas leakage is out put is zero to one, which is detected by

Microcontroller IC89C52 at pin P1.1.

Secondly we detect smoke, actually smoke sensor is very costly, then we

use self developed smoke sensor using a-stable multi-vibrator and out of that is

feed infrared transceiver cover in box.

For Smoke detection, we use infrared transmitter and receiver model. This

infrared sensor is operated at 36 KHz frequency. We use IC 555 as oscillator in

A-stable Multi-vibrator mode. At pin 3, i.e. output pin of this IC, we connect

infrared diode and by using variable resistance VR1 we can adjust 36 kHz

frequency of IC 555. Infrared diode emits infrared signal beam of 36 kHz

frequency, which is invisible to human eye. This beam falls on I.R. receiver. The

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receiver has three pins, +Vcc, GND & output. In normal condition i.e. when there

is beam, output of this sensor is zero i.e . logically low and when no beam falls on

sensor its output becomes +5V i.e. logically high. The output of sensor is

connected to ADC. This infrared transmitter and receiver are connected in front of

each other in closed box, so that in normal condition when there is no smoke, I.R.

beam falls on receiver and its output is logically low. When smoke occurs smoke

enters in the box through hole and gets collected in it. When density of smoke

increases, it cuts off the beam of I.R. and output of sensor changes from logically

low to high. This change of state is directly connected to pin no P1.2 of

microcontroller IC 89C52.

micro controller can read this status of signal and shown which system is detected

and shown on display 16x2 LCD,. This display has 8 data line D0 to D7 three

control line R/W, EN, RS and two supply line VCC and ground 1 contrast control

line and two line for backlight supply interfacing of display. At the same time

which system (gas leakage or smoke detect send message at remote location we

use SMS technology. The GSM network offers a wireless system, which extends

your reach to anywhere in the world. There are several means to tap onto this

SMS as a communication medium. One way is to use a direct data call to connect

a point-to-point data link from one place to another. Or, to log into the World-

Wide-Web via. GPRS. A simple method is also via Short Message System

(SMS). a system wants to exchange or send data or information from one point to

another.

We will describe here of how to use an AT command on mobile decoders to be as

a GSM communication information node. This will be the cheapest means to

create your own DIY remote messaging system. Connect the mobile decoder to

your micro controller via the Data Cable. You can connect it through the RS232

TTL converter, IC MAX 232 Which can convert signal from micro controller to

mobile decoder to its proper operating voltage +,- 12 volt D.C. Select the baud

rate of serial Communication to be 9600 bps (actually, the module will accept all

the baud rate setting, any selection will work). The other parameters are: Data

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Bits (8), Parity (None), With that, you are all set to test out the AT command with

the mobile decoder.

The following are some simple AT commands:

Call Control

AT Attention

ATA Answer Command

ATD Dial Command

ATH Hang Up Call

Send "AT" on serial port. The GSM mobile decoders will respond with an "OK".

This is the simplest command to tell the mobile decoder to go on attention. It

doesn't do anything. However, this is also a means to test if the decoder responds

on the baud rate and all the serial settings.

The following are some simple AT commands to do SMS.

SMS Commands

AT+CMGR Read Message

AT+CMGS Send Message

This mobile decoders circuit connects to the serial port of micro controller

through MAX 232 IC. Its function is to provide an input and an output port

capable of being remotely controlled using another mobile.

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Buzzer is used for audio indication for gas leakage and smoke detect, for

that purpose at microcontroller pin P1.7 is use, we use for driving buzzer driver

circuit is use which is detail of design folder control takes place by means of

sending SMS (Short text Messages Service). When the micro controller receives a

predefined of sensor(gas leakage or smoke detect) text message, like "gas is

leakage" or "smoke is detected", is send In this way we can receive massage at

remote station through SMS.

Capacitor Cr & R3 in fig are connected to RST pin of micro controller to

provide reset pulse when power is turn ON, so that program execution starts from

starting memory location 0000H. Quartz ceramic crystal is connected to pin 18 &

pin 19 for generation of machine cycle req. to execute an instruction ofmicrocontroller.

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D E S I G N I N G

Power supply design :

Power supply is the first and the most important part of our project. For our

project we require +5V regulated power supply with maximum current rating

500mA

Following basic building blocks are required to generate regulated power supply.

Step Down Transformer

Step down transformer is the first part of regulated power supply. To step down

the mains 230V A.C. we require step down transformer. Following are the main characteristic of

electronic transformer.

Step-

Rectifi Filter

Three

Terminal

Regulated O/P

VoltageMains 230 V

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1) Power transformers are usually designed to operate from source of low impedance

at a single freq.

2) It is required to construct with sufficient insulation of necessary dielectric

strength.

3) Transformer ratings are expressed in voltamp. The volt-amp of each secondary

winding or windings are added for the total secondary VA. To this are added the load

losses.

4) Temperature rise of a transformer is decided on two well-known factors i.e. losses

on transformer and heat dissipating or cooling facility provided unit.

Rectifier Unit

Rectifier unit is a ckt. which converts A.C. into pulsating D.C. Generally semi-

conducting diode is used as rectifying element due to its property of conducting current in one

direction only. Generally there are two types of rectifier.

1) Half wave rectifier

2) Full wave rectifier.

In half wave rectifier only half cycle of mains A.C. is rectified so its efficiency is

very poor. So we use full wave bridge type rectifier, in which four diodes are used. In each half

cycle, two diodes conduct at a time and we get maximum efficiency at o/p.

Following are the main advantages and disadvantages of a full-wave bridge type

rectifier ckt.

Advantages:

1) The need of center tapped transformer is eliminated.

2) The o/p is twice that of center tap circuit for the same secondary voltage.

3) The PIV rating of diode is half of the center tap circuit.

Disadvantages:

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1) It requires four diodes.

2) As during each half cycle of A.C. input, two diodes are conducting

therefore voltage drop in internal resistance of rectifying unit will be twice as

compared to center tap circuit.

Filter Circuit

Generally a rectifier is required to produce pure D.C. supply for using at various

places in the electronic circuit. However, the o/p of rectifier has pulsating character i.e. if such a

D.C. is applied to electronic circuit it will produce a hum i.e. it will contain A.C. and D.C.

components. The A.C. components are undesirable and must be kept away from the load. To do

so a filter circuit is used which removes (or filters out) the A.C. components reaching the load.

Obviously a filter circuit is installed between rectifier and voltage regulator. In our project we

use capacitor filter because of its low cost, small size and little weight and good characteristic.

Capacitors are connected in parallel to the rectifier o/p because it passes A.C. but does not pass

D.C. at all.

Three terminal voltage regulator

A voltage regulator is a ckt. that supplies constant voltage regardless of change in

load current. IC voltage regulators are versatile and relatively cheaper. The 7800 series consists

of three terminal positive voltage regulator. These ICs are designed as fixed voltage regulator

and with adequate heat sink, can deliver o/p current in excess of 1A. These devices do not

require external component. This IC also has internal thermal overload protection and internal

short circuit and current limiting protection. For our project we use 7805 voltage regulator IC.

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Design of Step down Transformer

The following information must be available to the designer before he

commences for the design of transformer.

1) Power Output.

2) Operating Voltage.

3) Frequency Range.

4) Efficiency and Regulation.

Size of core

Size of core is one of the first considerations in regard of weight and volume of

transformer. This depends on type of core and winding configuration used. Generally followingformula is used to find area or size of core.

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P1

Ai = -----------

0.87

Ai = Area of cross - section in Sq. cm. and

P1 = Primary voltage.

In transformer P1 = P2

For our project we required +5V regulated output. So transformer secondary

rating is 12V, 500mA.

So secondary power wattage is,

P2 = 12 x 500 x 10-3

w.

= 6w.

6

So Ai = 0.87

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= 2.62

Generally 10% of area should be added to core to accommodate all turns for low

Iron losses and compact size.

So Ai = 2.88.

Turns per volt

Turns per volt of transformer are given by relation

10,000

Turns / Volt = -----------------------

4.44 f Bm Ai

Here,

f is the frequency in Hz

Bm is flux density in Wb/m2

Ai is net area of cross section.

Following table gives the value of turns per volt for 50 Hz frequency.

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Flux density Wb/m2 1.14 1.01 0.91 0.83 0.76

Turns per volt 40/Ai 45/Ai 50/Ai 55/Ai 60/Ai

Generally lower the flux density better be quality of transformer.

For project for 50 Hz the turns per Volt for 0.91 Wb/m2 from above table.

Turns per Volt =50 / Ai

50

2.88

17

Thus for Primary winding = 220 x 17 = 3800.

& for Secondary winding = 12 x 17 = 204.

Wire size

As stated above size depends upon the current to be carried out by the winding,

which depends upon current density of 3.1 A/mm2. For less copper losses 1.6 A/mm2 or 2.4

A/mm2 may be used. Generally even size guage of wire are used.

Rectifier Design

R.M.S. Secondary voltage at secondary of transformer is 12V.

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So maximum voltage Vm across Secondary is

= Rms. Voltage x 2

= 12 x 2

= 16.97

D.C. O/p Voltage at rectifier O/p is

2 Vm

Vdc = ----------

2 x 16.97

= -----------------------

= 10.80 V

PIV rating of each diode is

PIV = 2 Vm.

= 2 x 16.97

= 34 V

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& maximum forward current which flow from each diode is 500mA.

So from above parameter we select diode IN 4007 from diode selection manual.

Design of Filter Capacitor

Formula for calculating filter capacitor is,

1

C = ----------------------

43 r f RL.

r = ripple present at o/p of rectifier.

(Which is maximum 0.1 for full wave rectifier.)

F = frequency of mains A.C.

RL = I/p impedance of voltage regulator IC.

1

C = ------------------------------

43 x 0.1 x 50 x 28= 1030 f

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1000 f.

And voltage rating of filter capacitor is double of Vdc i.e. rectifier o/p which is

20V. So we choose 1000 f / 25V filter capacitor.

IC 7805 (Voltage Regulator IC.)

1 2 3 Specifications :

Available o/p D.C. Voltage = + 5V.

Line Regulation = 0.03

Load Regulation = 0.5

Vin maximum = 35 V

Ripple Rejection = 66-80 (db)

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Design of I.R. Transmitter

In infrared transmission section IC 555 is wired as an As table multivibrator with

a center freq. Of an about 36 KHz. O/p of 555 is in square wave infrared LED is

connected to its o/p pin 3. The oscillator frequency. Can be shifted slightly using

variable resistance VR1.

For calculation of resistance, capacitor & o/p freq. Of As table

multivibrator using 555 the capacitor connected between pin 2.6 & GND is

periodically charge and discharge between 2 VCC/3 and VCC/3 respectively.

During charging period 0 < t < TC the voltage across capacitor will given

by

Vx = 2VCC/3 [ 1 exp { - t / RA + RB} C1] + VCC /3

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At time t = TC capacitor voltage Vx reaches to threshold

level of 2 VCC/3 so that

2/3 VCC = 2VCC/3 [ 1 exp { - TC /(RA + RB)C1} ] = VCC/3

solving charging time TC gives

TC = (RA + RB ) C1 Ln 2

= 0.693 (RA + RB) C1

During discharge period 0 < t < TD we have that

Vx = 2VCC /3 exp (-t1/ RBC1)

At time t1 = TD the voltage across the capacitor reaches the trigger level

of VCC/3 50 we have that Vx ( t = TD)

VCC/3 = 2VCC/3 exp ( -TD/ RBC1)

From this we obtain

TD = RBC1 ln2

= 0.693 RBC1

where,

TD & TC are charge & discharge Time so that total time T is

T = TD + TC

T = 0.693 (RA + 2RB) C1

So final equation for o/p freq. Is

F0 = 1/T

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= 1/ 0.693 (RA + 2RB) C1

F0 = 1.44

(RA + 2RB) C1

From this formula,

We know that req. freq. Of 36 KHz

We assume C1 = 0.001 uf

So 36 K Hz = 1.44

( RA + 2RB ) 0.001uf

(RA + 2RB = 1.44

36 x 103 x 0.001 x 10 -6

= 1.44

x 10-05

( RA + 2RB ) = 40 k ohm

if we again assume RA = 4.7 k ohm 50 2RB = 35.3 K ohm

so we select RB = 10 k ohm variable + 10 k ohm fix Resistance

i.e. RB = 20 k ohm

2 RB = 40 k ohm, = 35.3 K ohm

by charging RB variable 10 k ohm pot we adjust o/p freq. From 33 KHz

to 38 KHz . which is sufficient.

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The receiver uses an infrared sensor module which is commonly

used in color television for sensing the I. R. Signals from transmitter section.

Design for Buzzer Circuit

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Specification of buzzer is

Sound o/p > 95d at 12v d.c.

Oscillator frequency= 4 kHz

Current consumption

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So IC max =20 mA

Again we select transistor BC 547 for buzzer driver because its ic max is 80 mA

and it is low cost, easily available in market.

For common emitter configuration of transistor its current equation is

IB = Ic/

= 110 for BC 547 transistor

= 20 mA / 110

= 0.18mA

Applying kickoffs voltage low to loop of base of transistor

Vcc1 = IB RB + VBE

Vcc1=+5v dc VBE=0.7v for silicon transistor

RB = 5 - 0.7 / IB

RB = 4.3 / 0.18mA

RB = 23K

Selection for current limiting resistance for LED

As o/p of micro controller is equal to supply voltage i.e +5v dc

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If we directly connected LED to micro controller then very high current flowing

through it because internal resistance of led is very small about 5 to 8 ohm so it is

possibility to damage LED so we place current limiting resistance R in series with diode

the value of this resistance is calculated

From ohms low

V = R I

where

I= If safe forward current flowing through LED which normal intensity

glow and this value near about 8 to 10 mA

5 = R x 8mA

R = 625

So we select near about value 680 .

PCB DESIGNING

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Only two types of PCB boards are most popular

Single sided Boards

Double Sided Boards

1.Single Sided Boards:

Single Sided Boards are mostly used in entertainment electronics where

the manufacturing cost is to be kept minimum and there is no space limitation and

size limitation. In Single Sided Boards, component side doesnt have any track.

Also, on Single Sided Boards should be wherever a particular circuit can be

accommodated on such boards, the number of jumper wires on such boards are

more, but the designer should take care that the jumpers should be minimum.

2.Double Sided Boards: -

The Double Sided Boards are made with tracked on both sides; component

Seder is also having tracks. This is done to avoid jumpers and accommodation of

many components. These boards may be with plated through holes or without

plated through holes. If plated through holes are not there, the pad son both sides

of the PCB are to be connected by a connecting link. These are called as feed

through type boards.

PTH Printed Circuit Boards:

The Double Sided PCBs can be made with or without Plated Through

Holes. This means that the holes are made conductive. The two pads are

connected by the conducting material which avoids the need of feed through holes

is expensive. Therefore, PTH boards are only chosen where circuit complexity

and design do not leave any other choice. The size of PCB reduces drastically, as

the components can be mounted from both the sides. Once this board is developed

properly and proper workmanship is there, no faults and failures are there.

The problems of dry soldering, rewetting and birding are completely

eliminated by means of PTH boards. The cost of Soluble Dised PCB without

plated through holes is considerably low. In layout design, the care is taken that

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the component side have to be kept minimum in number of solder joints because

the replacing of such components is fairly difficult. A typical strategy is therefore

to realize the conductor as much as possible on the non- component side i.e.

trackside. These boards may be without or with masking i.e. green masking,

yellow masking, blue masking or red masking. Masking is done in order to avoid

the shorting of tracks and components, it also makes soldering easy, even amateur

mechanic or an inexperienced person can also do soldering on masked PCB. The

problem of signal interference due to close placement of tracks can be avoided by

masking he PCB.

General Rules For Designing Of PCB:

1) After selection of electronic circuit, make a block diagram of various circuits to

know various inter-connections required, which will help in reducing the number of

wires.

2) The designer should have the complete idea of the circuit regarding the function

and signal flows through.

3) Keep each and every component you need, while starting the designing.

4) Use of templates is essential if you are a new designer, if the design is manual i.e.

hand made and not with software such as Orcas, Auto CAD, pads, ideas, circuit maker,

etc.

5) Standard PCB size should be decided in the beginning only.

6) Preferably, layout ands artwork should be in 1:2 scales.

7) Sequential stages after PCB size is decided.

a) Component placement

b) Track routing i.e. lay-out

c) Artwork making with ink or ready-made tapes and pads.

8) While routing the tracks, carrying AC mains voltage, consider the safety rules

ands regulations.

9) In analog ands digital systems together, care should be taken that analog and

digital grounds will not mix with each other affecting the stability ands fluctuations in the

display.

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10) In power systems i.e. high current, the track width and the track spacing should

be as maximum as possible.

11) While placing the components on the PCB preferably the load on PCB, should be

evenly distributed to avoid the problems at completion stage during wave- soldering i.e.

warping of PCB etc.

12) To avoid weakening of the Pub tool, the perforation length should be kept

minimum i.e. < 40 mm.

13) For manually shouldered components vent i.e. cut pads should be provided to

avoid the blocking of holes during shouldering.

Component Placement:

14) Preferably, place the component in X-Y direction subjected to mechanical

construction.

15) All Components should be flat mounted i.e. flat placed to avoid of leads and for

easy requirements. However in case of space limitation the components such as resistors,

diodes, etc. may be mounted vertically which doesnt affect the performance.

16) In case of separate analog and digital ground; a capacitor should be connected in

between the analog and digital ground.

17) Orientation of multi-lead components (e.g. switches, ICs) should be such that axis

of component is perpendicular to the direction of solder wave.

18) Sufficient clearance is provided around component so that inversion or

replacement ands repair is easy.

19) The design should such that minimum jumpers are allowed.

20) It is preferable that, components like presets, coils, and trim pots, etc. which

alignment or calibration are placed in such that, they are accessible after the assembly of

the PCB on cabinet also.

21) If the components are not flush mounted, provide the sleeve for leads.

PCBTracks:

1.General tracks thickness should be 1.00 mm preferred.

2.For ground tracks thickness should be maximum.

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3.In case of space limitation, track thickness of 0.5 mm can be used except for

power tracks.

Always, ground > 2 Supply > 2 Signal

4.Generally, track length as short as possible; subjected to component placement.

5.Use copper patches, wherever possible to add strength of PCB.

6.Provide minimum 0.8 mm gap may be 0.5 mm except power tracks.

7.High frequency or high current or high voltage tracks should be away from each

other.

PCB LAYOUT

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Gas PCB :-

Power supply PCB

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Flow chart

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PROGRAM

'THIS IS PROGRAM FOR PROJECT GSM BASE GAS SMOKE DETECTION

SYSTEM

Buzzer Alias P1.1

Gas_sensor Alias P2.1

Smoke_sensor Alias P2.0

Reset Buzzer

Declare Sub Gas

Declare Sub Smoke

Declare Sub Send_sms_gas

Declare Sub Send_sms_smoke

Cls

Lcd "GSM Base Gas &"

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Lowerline

Lcd "Smoke Detection"

Wait 3

Cls

Do

Lcd "Searching For"

Lowerline

Lcd " Gas & Smoke"

If Gas_sensor = 0 Then

Gas

Elseif Smoke_sensor = 1 Then

Smoke

Loop

Sub Gas

Cls

Lcd " Gas is Detected"

Set Buzzer

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Wait 2

Lowerline

Lcd "SMS is send"

Send_sms_gas

Wait 2

Send_sms_gas

End Sub

Sub Smoke

Cls

Lcd " Smoke is Detected"

Set Buzzer

Wait 2

Lowerline

Lcd "SMS is send"

Send_sms_smoke

Wait 2

Send_sms_smoke

End Sub

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Sub Send_sms_gas

Print "AT+CMGF=1"

Print "AT+CMGS="9823264825"

Waitms 100

Print "Gas is Detected" ; Chr(26)

End Sub

Sub Send_sms_smoke

Print "AT+CMGF=1"

Print "AT+CMGS="9823264825"

Print "Smoke is Detected" ; Chr(26)

End Sub

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GSM

Global system for mobile communication. A digital cellular phone

technology based on TDMA that is the predominant system in Europe, but also

used worldwide. Developed in the 1980s, GSM was first deployed in7 European

countries in 1992. It operates in the 900 MHz & 1.8GHz bands in Europe & the

1.9 GHz in the US. Based on a circuit switched system that divides each 200kHz

time slots. GSM defines the entire cellular system, not just the TDMA air

interface. A fast growing communications technology, there were more than 250

million GSM users early in 2000. By mid-2004. The one billionth GSM customer

was connected,. There are 5 different cell sizes in a GSM network- macro, mirco,

pico, femto & umbrella cells. The coverage area of each cell varies according to

the implementation environment . Macro cells can be regarded as cells where the

base station antenna is installed on a mast or a building above average roof top

level. Miro cells are cells whose antenna height is under average roof top level;

they are mainly used indoors. Femto cells are cells designed for use in residential

or small business environments & connect to the service providers network via a

broadband internet connections. Umbrella cells are used to cover shadowedregions of smaller cells & fill in gaps in coverage between those cells.

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ADVANTAGES

1) Using any type of mobile we communicate with our project there is no

requirement of specific company mobile.

2) There is no limit of range to communicate with project at remote location.

3) Operation is so easy and simple.

4) Project operated on 5v dc so less power consumption operated on battery

also.

5) Using micro controller project is compact and portable.

6) It is aimed at human protection and hence vary economical.

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APPLICATIONS

1)In hazardous area SMS alert system.

2) After modifying same project we use it at security system.

3) By changing smoke sensor with carbon sensor we use In government rest

houses to maintain quality of air.

4) In Rural area .

LIMITATIONS

1) In our project we use poor quality sensor for demonstration.

2) The set point value is fix in program in case of change this value we can change

3) In our project we send SMS at only two mobile numbers.

4) We does not provide any type of battery back up to our system so in case of

power fail it does not work.

5) In case of micro controller failure our project become Dade.

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CONCLUSION

From this project we can conclude that this is permanently installed

system capable of detecting minutest gas leakage and prevent hazardous

problems. This project can be implemented at low cost and manpower is not

required .

From this system ,we can alert the people at service station , at nearby

places and also at remote places through GSM technology.

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TROUBLESHOOTING

1) After etching of P.C.B. make sure all P.C.B. track is connected to each other

using continuity test. If any one track damage then connect wire to it.

2) Connect project to mains 230v ac supply and turn on power and see status of

power on led of power supply if LED does not glow check mains quad, output of

step down transformer, out put of bridge rectifier and voltage regulator Ic.

3) Give supply to mobile decoder and check its output on TXD and RXD pin of

micro controller.

4) Give external volt to relay and check the o/p at relay contact by continuity.

5) Check Reset pulse at pin no 9 of micro controller ic 89c51 it must be high to

low when power is applied to it.

6) Check crystal frequency at pin 19 of micro controller ic it must be 11.059MHz.

7) Check out put of display section.

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GSM

Global system for mobile communication. A digital cellular phone

technology based on TDMA that is the predominant system in Europe, but also

used worldwide. Developed in the 1980s, GSM was first deployed in7 European

countries in 1992. It operates in the 900 MHz & 1.8GHz bands in Europe & the

1.9 GHz in the US. Based on a circuit switched system that divides each 200kHz

time slots. GSM defines the entire cellular system, not just the TDMA air

interface. A fast growing communications technology, there were more than 250

million GSM users early in 2000. By mid-2004. The one billionth GSM customer

was connected,. There are 5 different cell sizes in a GSM network- macro, mirco,

pico, femto & umbrella cells. The coverage area of each cell varies according to

the implementation environment . Macro cells can be regarded as cells where the

base station antenna is installed on a mast or a building above average roof top

level. Miro cells are cells whose antenna height is under average roof top level;

they are mainly used indoors. Femto cells are cells designed for use in residential

or small business environments & connect to the service providers network via a

broadband internet connections. Umbrella cells are used to cover shadowed

regions of smaller cells & fill in gaps in coverage between those cells.

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SIMCOM GSM/GPRS Modem

GSM GPRS modem for GSM 900 / GSM 1800 / GSM 1900

We are pleased to present the new fully featured SIMCOM GSM based Modem

with most of the functions taken care on board .This PCB is thoroughly tested and

qualified at Pulraj Electronics-Mumbai and ready to serve the customers.

This GSM modem is a highly flexible plug and play GSM 900 / GSM 1800 / GSM 1900

modem for direct and easy integration RS232, voltage range for the power supply

and audio interface make this device perfect solution for system integrators and

single user. Voice, Data/Fax, SMS,GPRS, integrated TCP/IP stack,RTC and other

features like the GSM / GPRS.

GSM modem characteristics

i. Triband GSM GPRS modem (EGSM 900/1800 / 1900 MHz )

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ii. Designed for GPRS, data, fax, SMS and voice applications

iii. GPRS multi-slot class 10

iv. GPRS mobile station class B

v. Designed for GPRS, data, fax, SMS and voice applications

vi. Fully compliant with GSM Phase 2/2+ specifications

vii. Built-in TCP/IP Protocol

viii. Built-in RTC in the module.

ix. AT Command based

Specifications for Data

i. GPRS class 10: max 85.6 kbps (downlink)

ii. PBCCH Support

iii. Coding schemes CS 1,2,3,4

iv. CDS up to 14.4 kbps

v. USSD

vi. Non transparent mode

vii. PPP - stack

Specifications for Fax

i. Group 3, Class 1

Specifications for SMS via GSM & GPRS

i. Point-to-point MO & MT

ii. SMS cell broadcast

iii. Text & PDU mode

Specifications for voice

i. Tricodec

ii. Half rate (HR)

iii. Full rate (FR)

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iv. Enhanced Full rate ( EFR)

v. Noise reduction

Power Supply:Use AC DC Power Adaptor with following ratings

i. Input AC Voltage: 230V

ii. Output DC Voltage : 12V

iii. Output DC Current : 2A

iv. Polarity : Centre +ve & Outside ve

General characteristics

i. Input voltage: 9V-12V

ii. Input current: 15mA in idle mode, 110mA in communication

iii. Temperature range: Operating -20 to +55 degree Celsius; Storage -25 to

+70 degree Celsius

Interfaces

i. RS-232 through D-TYPE 9 pin connector

ii. Serial port baud rate 1200 to 115200 bps

iii. RJ11 voice connector

iv. Power supply through DC jacket

v. SMA antenna connector

vi. Toggle spring/Flap Opening type SIM holder

vii. LED status of GSM / GPRS module

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LIST OF COMPONENTS

SEMICONDUCTOR ICs

Table :IC Components

Sr No. Components Value/Specification Cost Quantity

1. IC1 89C52 85/- 1

2. IC2 MAX232 35/- 1

3. IC3 555 8/- 1

4. IC4 7805 12/- 1

RESISTORS (All resistors of watt ,carbon film type)

1)Fixed resistances

Table :Fixed resistances of different values

Sr No. Component Value/Specification(Ohm) Cost Quantity

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1 R1 22K Rs.25paisa 1

2 R2 680 Rs.25paisa 1

3 R3 10K Rs.25paisa 1

4 RA 4.7K Rs.25paisa 1

5 RB 10K Rs.25paisa 1

6 R6

7 R7

8 R8

9 R9

10 R10

R11

2) Variable Resistances:Table: Variable resistances of different values

Sr No. Component Value/Specification Cost Quantity

1 VR1 10K Rs.3/- 1

2 VR2 10K Rs.3/- 1

3 VR3

4 VR4

5 VR5

6 VR6

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CAPACITORS

Sr No Component Value/Specification Cost Quantity

1 Cr 10uf/63v electrolytic Rs.4/- 1

2 Ca 33pf disk type ceramic Rs.1/- 1

3 Cb 33pf disk type ceramic Rs. 1/- 1

4 C1 0.001 disk type ceramic Rs.1/- 1

5 C2 0.01 disk type ceramic Rs.1/- 1

6 C4 1000uf/25v electrolytic Rs.8/- 1




10 C22 10uf/63v electrolytic Rs.4/- 111 C23 10uf/63v electrolytic Rs.4/- 1

12 C

DIODES

Table:Diodes with different values

Sr No. Component Value/Specification Cost Quantity

1 D1 1N4007(p-n junction) Rs.1/- 1

2 D2 1N4007(p-n junction) Rs.1/- 1

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BUZZER :

QUARTZ CERAMIC BUZZER :-Rs.40/-

16*2 ALPHANUMERIC LCD DISPLAY:-Rs.750/-

GAS SENSOR:-Rs.550/-

SMOKE SENSOR

IR TRANSMITTER-RECEIVER PAIR:-Rs.125/-

TRANSFORMER 230V PRIMARY TO 0-15V-1Asec:-Rs.85/-

GSM MODEM:-Rs.5000/-

MISCELANIOUS:-Rs.1000/-

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BIBLIOGRAPHY

1) Programming and customizing the 8051 micro controller

Author---Myke Predko

Publications---TATA McGraw-HILL

2) The 8051 Micro controller Architecture, Programming & Application

Author---Kenneth J.Ayala

Publication---Pen ram Inter national publication

3) Opto Electronic Ckt Manual

Author---R.M. Marston

Publication---B.P.B. publication

4) Microprocessor Data Hand book

B.P.B. Publication

5) Towers International Transistor Selector

B.P.B. Publication

6) A Monogram on Electronic circuit Design Principal

Author---N.C.GOYAL-- R.K.KHETANPublication--- KHANNA

publication

7) Linear Integrated circuit

Author---Ramakant Gayakwad

Publication--- PH hall publication

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8)Elecktor-Electronics (magazine)

European Telecommunications Standards Institute (ETSI):

http://www.etsi.org/

Ericsson developer zone:

http://www.ericsson.com/mobilityworld/

http://www.lancos.com/

Unofficial AT-command compatibility table for various phones:

http://gatling.ikk.sztaki.hu/~kissg/gsm/at+c.html

WWW.ATMEL.com
http://gatling.ikk.sztaki.hu/~kissg/gsm/at+c.htmlhttp://gatling.ikk.sztaki.hu/~kissg/gsm/at+c.html

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39989337-39506021-Project