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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. This
means 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 of Gas 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 gas≥5
Sensing Resistance 40 to 400KΩ in air Ω Ohms
Response Time ≤10s Seconds
Resume Time ≤30s Seconds
Heating Resistance 31Ω±3Ω Ω Ohms
Heating Current ≤180mA mA
Heater Voltage 5V±0.2V 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 of
microcontroller.
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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-down
Rectifier
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 volt–amp. 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 following
formula 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 = ----------
π
2 x 16.97
= -----------------------
π
= 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 = ----------------------
4√3 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 = ------------------------------
4√3 x 0.1 x 50 x 28
= 1030 µ f
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≅ 1000 µ f.
And voltage rating of filter capacitor is double of Vdc i.e. rectifier o/p which is
20V. So we choose 1000 µ 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<20mA
Operating temperature range = -20 deg. To +50 deg. Centigrade
Operating voltage range = 3v to 15 v dc
From specification of buzzer current consumption of buzzer coil is 20mA
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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/β
β = 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 = 23KΩ
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 Ω
So we select near about value 680Ω .
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 doesn’t 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 PCB’s 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 doesn’t 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.
PCB Tracks:
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 shadowed
regions 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 IC’s
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 ¼ 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
7 C19 10uf/63v electrolytic Rs.4/- 1
8 C20 10uf/63v electrolytic Rs.4/- 1
9 C21 10uf/63v electrolytic Rs.4/- 1
10 C22 10uf/63v electrolytic Rs.4/- 1
11 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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3 D3 1N4007(p-n junction) Rs.1/- 1
4 D4 1N4007(p-n junction) Rs.1/- 1
5 Zener diode 1
6 Zener diode 2
TRANSISTORS
Table of Transistors
Sr No. Component Value/Specification Cost Quantity
1 T1 BC547 Rs.4/- 1
2 T2
CRYSTALS
Table : Different crystal with their oscillating frequency.
Sr No. Component Value/Specification Cost Quantity
1 X1 11.0592MHz Rs.22/- 1
SWITHES:
1.PUSH TO ON TYPE PCB MOUNTED :-Rs.12/-
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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
