A Vehicular Wireless Sensor Network for Vehicle Emissions Monitoring

A VEHICULAR WIRELESS SENSOR NETWORK FOR VEHICLE EMISSIONS MONITORING

1. ABSTRACT

AIM:

The main aim of this project is to design a wireless sensor network for vehicle to calculate the

vehicle emissions using sensors.

PURPOSE:

The purpose of the project is to calculate the quantity of CO released from the vehicle and

to transmit this data to the concern R.T.A using GSM technologies.

BLOCK DIAGRAM:

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MICRO CONTOLLER

POWER SUPPLY

CO

SENSOR

ADC 0804

GSM

DC MOTOR DRIVERS

DC MOTORS

LCD


POWER SUPPLY:

DESCRIPTION:

In this project we are detecting gas released will be measured and given to the ADC as

input. ADC will convert this analogical data into digital format and forwards to the

controller. Microcontroller compares this data with predefined data; if it exceeds the

threshold then GSM is activated. GSM modules will transmits this data to the mobile no

which is located in the R.T.A office.

SOFTWARES:

1. EMBEDDED C

2. KEIL IDE

3. UC-FLASH

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Step DownTransformer

BridgeRectifier

FilterCircuit

Regulator section


HARDWARES:

1. MICRO CONTROLLER

2. POWER SUPPLY

3. GSM

4. LCD

5. DC MOTOR DRIVERS

6. DC MOTORS

RESULT:

As a result vehicular wireless sensor network is useful to monitor the vehicle emissions

and track the vehicle position. By this project information regarding vehicle is

transmitted to the RTA when they exceeds threshold.

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2. I NTRODUCTION

An embedded system is a special-purpose system in which the computer is

completely encapsulated by or dedicated to the device or system it controls. Unlike a

general-purpose computer, such as a personal computer, an embedded system performs

one or a few pre-defined tasks, usually with very specific requirements. Since the system

is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost

of the product. Embedded systems are often mass-produced, benefiting from economies

of scale.

Introduction to GSM:

Global System for Mobile Communication (GSM) is a set of ETSI standards

specifying the infrastructure for a digital cellular service. The standard is used in approx.

85 countries in the world including such locations as India, Europe, Japan and Australia1.

GSM (Global System for Mobile communication) is a digital mobile telephone

system that is widely used in many parts of the world. GSM uses a variation of

Frequency Division Multiple Access (FDMA) and is the most widely used of the three

digital wireless telephone technologies (TDMA, GSM, and CDMA). GSM digitizes and

compresses data, then sends it down a channel with two other streams of user data, each

in its own time slot. GSM operates in the 900MHz, 1800MHz, or 1900 MHz frequency

bands.

GSM has been the backbone of the phenomenal success in mobile telecoms

over the last decade. Now, at the dawn of the era of true broadband services, GSM

continues to evolve to meet new demands. One of GSM's great strengths is its

international roaming capability, giving consumers a seamless service. This has been a

vital driver in growth, with around 300 million. In the Americas, today's 7 million

subscribers are set to grow rapidly, with market potential of 500 million in population,

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http://en.wikipedia.org/wiki/Economies_of_scale

http://en.wikipedia.org/wiki/Economies_of_scale

http://en.wikipedia.org/wiki/Personal_computer

http://en.wikipedia.org/wiki/Computer


due to the introduction of GSM 800, which allows operators using the 800 MHz band to

have access to GSM technology too.

GSM together with other technologies is part of an evolution of wireless mobile

telecommunication that includes High-Speed Circuit-Switched Data (HCSD), General

Packet Radio System (GPRS), Enhanced Data GSM Environment (EDGE), and

Universal Mobile Telecommunications Service (UMTS).

Architecture:

When a user dials a GSM mobile subscriber's MSISDN, the PSTN routes the call

to the Home MSC based on the dialed telephone number. The MSC must then query the

HLR based on the MSISDN, to attain routing information required to route the call to the

subscribers' current location.

The MSC stores global title translation tables that are used to determine the HLR

associated with the MSISDN. When only one HLR exists, the translation tables are

trivial. When more than one HLR is used however, the translations become extremely

challenging; with one translation record per subscriber (see the example below). Having

determined the appropriate HLR address, the MSC sends a Routing Information Request

to it.

When the HLR receives the Routing Information Request, it maps the MSISDN

to the IMSI, and ascertains the subscribers' profile including the current VLR at which

the subscriber is registered. The HLR then queries the VLR for a Mobile Station

Roaming Number (MSRN). The MSRN is essentially an ISDN telephone number at

which the mobile subscriber can currently be reached. The MSRN is a temporary number

that is valid only for the duration of a single call.

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The HLR generates a response message, which includes the MSRN, and sends it

back across the SS7 network to the MSC. Finally, the MSC attempts to complete the call

using the MSRN provided.

GSM security issues such as theft of service, privacy, and legal interception

continue to raise significant interest in the GSM community. The purpose of this portal is

to raise awareness of these issues with GSM security.

The mobile communications has become one of the driving forces of the

digital revolution. Everyday, millions of people are making phone calls by pressing a few

buttons. Little is known about how one person's voice reaches the other person's phone

that is thousands of miles away. Even less is known about the security measures and

protection behind the system. The complexity of the cell phone is increasing as people

begin sending text messages and digital pictures to their friends and family. The cell

phone is slowly turning into a handheld computer. All the features and advancements in

cell phone technology require a backbone to support it. The system has to provide

security and the capability for growth to accommodate future enhancements. General

System for Mobile Communications, GSM, is one of the many solutions out there. GSM

has been dubbed the "Wireless Revolution" and it doesn't take much to realize why GSM

provides a secure and confidential method of communication.

The present project A VEHICULAR WIRELESS SENSOR NETWORK FOR VEHICLE

EMISSIONS MONITORING” is the one which gives the information of the parameters

if any sensed parameter is out of pre-defined threshold value indicating pre-disaster, then

microcontroller sends the SMS to pre-stored mobile no. indicating Pre-Disaster.

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http://www.tech-faq.com/cell-phone-reviews.shtml


3. Block Diagram:

Fig.1: Block diagram

4.BLOCK DIAGRAM EXPLINATION

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MICRO CONTOLLER

POWER SUPPLY

CO

SENSOR

ADC 0804

GSM

DC MOTOR DRIVERS

DC MOTORS

LCD


MAX- 232:

To allow compatibility among data communication equipment made by various

manufactures, an interfacing standard called RS232 was set by the Electronic Industries

Association (EIA).This RS-232 standard is used in PCs and numerous types of equipment

.However, since the standard was set long before the advent of the TTL logic family, its

input and output voltage levels are not TTL compatible. In RS-232 ,a 1 is represented by

-3 to -25V,while a 0 bit is +3 to +25V,making -3 to +3 undefined. For this reason, to

connect any RS-232 to a microcontroller system we must use voltage converters such as

MAX232 to convert the TTL logic levels to the RS-232 voltage levels and vice versa.

So here we are using this MAX-232 to have compatibility between the GSM and

microcontroller.

GSM MODEM

Here we are using GSM MODEM to communicate with the mobile phone to

which we are going to send the message. Here modem is used to send the messages to the

concern person if any pre disaster is occurred in the industry.

GSM consists of some AT commands using which messages are generated.

POWER SUPPLY

A variable regulated power supply, also called a variable bench power supply, is

one where you can continuously adjust the output voltage to your requirements. Varying

the output of the power supply is the recommended way to test a project after having

double checked parts placement against circuit drawings and the parts placement guide.

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This type of regulation is ideal for having a simple variable bench power supply. Actually

this is quite important because one of the first projects a hobbyist should undertake is the

construction of a variable regulated power supply. While a dedicated supply is quite

handy e.g. 5V or 12V, it's much handier to have a variable supply on hand, especially for

testing. Most digital logic circuits and processors need a 5 volt power supply. To use

these parts we need to build a regulated 5 volt source. Usually you start with an

unregulated power supply ranging from 9 volts to 24 volts DC (A 12 volt power supply is

included with the Beginner Kit and the Microcontroller Beginner Kit.). To make a 5 volt

power supply, we use a LM7805 voltage regulator IC.

The LM7805 is simple to use. You simply connect the positive lead of your

unregulated DC power supply (anything from 9VDC to 24VDC) to the Input pin, connect

the negative lead to the Common pin and then when you turn on the power, you get a 5

volt supply from the Output pin.

CO SENSOR

Here a gas sensor is used to identify if any gas leakage. If any gas leakage occurs

then a message will be sent to the concern person.

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http://www.iguanalabs.com/mbkit.htm

http://www.iguanalabs.com/1stled.htm


5. Schematic

Fig.2: Schematic

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6. Schematic Description

9th pin is connected reset circuit which includes a capacitor and a resister.

MAX232:

The 11th and 12th pins of MAX are interfaced to 11th and 10th pins of controller

respectively.

The 13th and 14th pins of MAX are interfaced to 3rd and 2nd pins of DB9 connector

which is indirectly fitted to GSM modem.

The 5th pin DB9 is GND.

CO sensor is connected to P1.0 and DC motor is connected to P1.1.

LCD is connected to P0. And lcd control pins are connected to P2.5, P2.6, P2.7

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7. Hardware Components

INTRODUCTION TO 8051MICROCONTROLLER

In 1981,Intel corporation introduced an 8 bit microcontroller called the 8051.This

microcontroller had 128 bytes of RAM,4K bytes of on-chip ROM, two timers, one serial

port ,and 4 ports(each 8-bits wide)all on single chip. At that time it was also referred to as

a “system on a chip”.

The 8051 is an 8-bit processor, meaning that the CPU can work

on only 8-bits of data at a time. Data larger than 8-bits has to be broken into 8-bit pieces

to be processed by the CPU. The 8051 can have a maximum of 64K bytes of ROM, many

manufacturers have put only 4Kbytes on chip.

Features:

Compatible with MCS-51 Products

4K Bytes of In-System Reprogrammable Flash Memory – Endurance: 1000

Write/Erase Cycles.

Fully Static Operation: 0Hz to 24MHz

Three-level Program Memory Lock

128 x 8- bit Internal RAM

32 Programmable I/O Lines

Two 16-bit Timer/Counters

Six Interrupt Sources

Programmable Serial Channel

Low-power Idle and Power-down Modes

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INTRODUCTION TO ATMEL MICROCONTROLLER:

SERIES: 89C51 Family, TECHNOLOGY: CMOS

The major Features of 8-bit Micro controller ATMEL 89C51 :

8 Bit CPU optimized for control applications

Extensive Boolean processing (Single - bit Logic ) Capabilities.

On - Chip Flash Program Memory

On - Chip Data RAM

Bi-directional and Individually Addressable I/O Lines

Multiple 16-Bit Timer/Counters

Full Duplex UART

Multiple Source / Vector / Priority Interrupt Structure

On - Chip Oscillator and Clock circuitry.

On - Chip EEPROM

SPI Serial Bus Interface

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Fig.3: Block Diagram

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COUNTERINPUTS

EXTERNALINTERRUPT

S

INTERRUPTCONTROL

ON-CHIPFLASH ON-CHIP

RAM

TIMER 1

TIMER 0

CPU

OSC BUSCONTROL

4 I/O PORTS

SERILPORT

PO P2 P1 P3 TXD RXD

ON-CHIPRAM


For more information on the individual devices and features, refer to the

Hardware Descriptions and Data Sheets of the specific device.

Fig. 4: Oscillator Connection.

The P89C51 provides the following standard features: 4K bytes of Flash, 128

bytes of RAM, 32 I/O lines, two 16-bit timer/counters, five vector two-level interrupt

architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition,

the P89C51 is designed with static logic for operation down to zero frequency and

supports two software selectable power saving modes. The Idle Mode stops the CPU

while allowing the RAM, timer/counters, serial port and interrupt system to continue

functioning. The Power-down Mode saves the RAM contents but freezes the oscillator

disabling all other chip functions until the next hardware reset.

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Memory Organization

Fig.5: Memory Structure of the 8051

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External

EA = 0

External

EA = 1

External

FFFFH

0000

INTERNAL

FF

00

EXTERNAL

FFFFH

PROGRAM MEMORY

DATA MEMORY

RD WRPSEN


Memory Organization

Program Memory:

Figure 4 shows a map of the lower part of the program memory.

After reset, the CPU begins execution from location 0000H. As shown in fig.4, each

interrupt is assigned a fixed location in program memory. The interrupt causes the CPU

to jump to that location, where it executes the service routine. External Interrupt 0, for

example, is assigned to location 0003H. If External Interrupt 0 is used, its service routine

must begin at location 0003H. If the interrupt is not used, its service location is available

as general purpose.

Fig.6: Program Memory

Program memory addresses are always 16 bits wide, even though the actual

amount o program memory used may be less than 64Kbytes. External program execution

sacrifices two of the 8-bit ports, P0 and P2, to the function of addressing the program

memory.

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(0033)H

002BH

0023H

001BH

0013H

000BH

0003H

0000H

8 bytesINTERRUPT LOCATIONS

RESET


Data Memory

The right half of Figure 3 shows the internal and external data memory spaces

available on Philips Flash microcontrollers. Fig.6 shows a hardware configuration for

accessing up to 2K bytes of external RAM. In this case, the CPU executes from internal

flash. Port0 serves as a multiplexed address/data bus to the RAM, and 3 lines of Port 2

are used to page the RAM. The CPU generates RD and WR signals as needed during

external RAM accesses. You can assign up to 64K bytes of external data memory.

External data memory addresses can be either 1 or 2bytes wide. One-byte addresses are

often used in conjunction with one or more other I/O lines to page the RAM, as shown in

Fig.6. Two-byte addresses can also be used, in which case the high address byte is

emitted at Port2.

Internal data memory addresses are always 1 byte wide, which implies an address

space of only 256bytes. However, the addressing modes for internal RAM can infact

accommodate 384 bytes. Direct addresses higher than 7FH access one memory space and

indirect addresses higher than 7FH access a different memory space. Thus, Figure.7

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ACCESSIBLE BY INDIRECT ADDRESSING

ONLY.

ACCESSIBLE BY DIRECT

ADDRESSING ONLY

ACCESSIBLE BY INDIRECT ADDRESSING AND DIRECT ADDRESSING

Fig.7: Internal Data Memory

Upper 128

Lower 128

80H7FH

00

FFH FFH

80H

Special register function

PortsStatus and control bitsTimersRegistersStack pointerAccumulator(etc)


shows the Upper 128 and SFR space occupying the same block of addresses, 80H

through FFH, although they are physically separate entities. Figure.8 shows how the

lower 128 bytes of RAM are mapped. The lowest 32 bytes are grouped into 4 banks of 8

registers. Program instructions call out these registers as R0 through R7. Two bits in the

Program Status Word (PSW) select which register bank is in use. This architecture allows

more efficient use of code space, since register instructions are shorter than instructions

that use direct addressing.

Fig.8: The lower 128 bytes of Internal RAM

The next 16 bytes above the register banks form a block of bit-addressable

memory space. The microcontroller instruction set includes a wide selection of single-bit

instructions, and these instructions can directly address the 128 bits in this area. These bit

addresses are 00H through 7FH. All of the bytes in the Lower 128 can be accessed by

either direct or indirect addressing.

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The major Features of 8-bit Micro controller ATMEL 89C51 :

8 Bit CPU optimized for control applications

Extensive Boolean processing (Single - bit Logic) Capabilities.

On - Chip Flash Program Memory

On - Chip Data RAM

Bi-directional and Individually Addressable I/O Lines

Multiple 16-Bit Timer/Counters

Full Duplex UART

Multiple Source / Vector / Priority Interrupt Structure

On - Chip Oscillator and Clock circuitry.

On - Chip EEPROM

SPI Serial Bus Interface

GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS

Definition:

Global system for mobile communication (GSM) is a globally accepted standard

for digital cellular communication. GSM is the name of a standardization group

established in 1982 to create a common European mobile telephone standard that would

formulate specifications for a pan-European mobile cellular radio system operating at 900

MHz It is estimated that many countries outside of Europe will join the GSM partnership.

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Description:

GSM, the Global System for Mobile communications, is a digital cellular

communications system, which has rapidly gained acceptance and market share

worldwide, although it was initially developed in a European context. In addition to

digital transmission, GSM incorporates many advanced services and features, including

ISDN compatibility and worldwide roaming in other GSM networks. The advanced

services and architecture of GSM have made it a model for future third-generation

cellular systems, such as UMTS. This paper will give an overview of the services offered

by GSM, the system architecture, the radio transmission

ISDN compatibility and worldwide roaming in other GSM networks. The advanced

services and architecture of GSM have made it a model for future third-generation

cellular systems, such as UMTS. This paper will give an overview of the services offered

by GSM, the system architecture, the radio transmission

Fig.9: structure of a GSM network

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GSM Modems:

A GSM modem can be an external modem device, such as the Wavecom FASTRACK

Modem. Insert a GSM SIM card into this modem, and connect the modem to an

available serial port on your computer.

A GSM modem can be a PC Card installed in a notebook computer, such as the Nokia

Card Phone.

A GSM modem could also be a standard GSM mobile phone with the appropriate cable

and software driver to connect to a serial port on your computer. Phones such as the

Nokia 7110 with a DLR-3 cable, or various Ericsson phones, are often used for this

purpose.

A dedicated GSM modem (external or PC Card) is usually preferable to a GSM mobile

phone. This is because of some compatibility issues that can exist with mobile phones.

For example, if you wish to be able to receive inbound MMS messages with your

gateway, and you are using a mobile phone as your modem, you must utilize a mobile

phone that does not support WAP push or MMS. This is because the mobile phone

automatically processes these messages, without forwarding them via the modem

interface. Similarly some mobile phones will not allow you to correctly receive SMS text

messages longer than 160 bytes (known as “concatenated SMS” or “long SMS”). This is

because these long messages are actually sent as separate SMS messages, and the phone

attempts to reassemble the message before forwarding via the modem interface. (We’ve

observed this latter problem utilizing the Ericsson R380, while it does not appear to be a

problem with many other Ericsson models.)

When you install your GSM modem, or connect your GSM mobile phone to the

computer, be sure to install the appropriate Windows modem driver from the device

manufacturer. To simplify configuration, the Now SMS/MMS Gateway will

communicate with the device via this driver. An additional benefit of utilizing this driver

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is that you can use Windows diagnostics to ensure that the modem is communicating

properly with the computer.

The Now SMS/MMS gateway can simultaneously support multiple modems, provided

that your computer hardware has the available communications port resources.

Fig.10: GSM smart modem

Architecture of the GSM network

A GSM network is composed of several functional entities, whose functions and

interfaces are specified. Figure 1 shows the layout of a generic GSM network. The GSM

network can be divided into three broad parts. The Mobile Station is carried by the

subscriber. The Base Station Subsystem controls the radio link with the Mobile Station.

The Network Subsystem, the main part of which is the Mobile services Switching Center

(MSC), performs the switching of calls between the mobile users, and between mobile

and fixed network users. The MSC also handles the mobility management operations.

Not shown are the Operations

A GSM network is composed of several functional entities, whose functions and

interfaces are specified. Figure 1 shows the layout of a generic GSM network. The GSM

network can be divided into three broad parts. Subscriber carries the Mobile Station. The

Base Station Subsystem controls the radio link with the Mobile Station. The Network

Subsystem, the main part of which is the Mobile services Switching Center (MSC),

23S.R.T.I.S.T-ECE


performs the switching of calls between the mobile users, and between mobile and fixed

network users. The MSC also handles the mobility management operations. Not shown is

the Operations intendance Center, which oversees the proper operation and setup of the

network. The Mobile Station and the Base Station Subsystem communicate across the

Um interface, also known as the air interface or radio link. The Base Station Subsystem

communicates with the Mobile services Switching Center across the A interface.

Fig.11: General architecture of a GSM network

Mobile Station:

The mobile station (MS) consists of the mobile equipment (the terminal) and a smart card

called the Subscriber Identity Module (SIM). The SIM provides personal mobility, so that

the user can have access to subscribed services irrespective of a specific terminal. By

inserting the SIM card into another GSM terminal, the user is able to receive calls at that

terminal, make calls from that terminal, and receive other subscribed services.

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The mobile equipment is uniquely identified by the International Mobile Equipment

Identity (IMEI). The SIM card contains the International Mobile Subscriber Identity

(IMSI) used to identify the subscriber to the system, a secret key for authentication, and

other information. The IMEI and the IMSI are independent, thereby allowing personal

mobility. The SIM card may be protected against unauthorized use by a password or

personal identity number.

Base Station Subsystem:

The Base Station Subsystem is composed of two parts, the Base Transceiver Station

(BTS) and the Base Station Controller (BSC). These communicate across the

standardized Abis interface, allowing (as in the rest of the system) operation between

components made by different suppliers.

The Base Transceiver Station houses the radio transceivers that define a cell and handles

the radio-link protocols with the Mobile Station. In a large urban area, there will

potentially be a large number of BTSs deployed, thus the requirements for a BTS are

ruggedness, reliability, portability, and minimum cost.

The Base Station Controller manages the radio resources for one or more BTSs. It

handles radio-channel setup, frequency hopping, and handovers, as described below. The

BSC is the connection between the mobile station and the Mobile service Switching

Center (MSC).

Network Subsystem

The central component of the Network Subsystem is the Mobile services Switching

Center (MSC). It acts like a normal switching node of the PSTN or ISDN, and

additionally provides all the functionality needed to handle a mobile subscriber, such as

registration, authentication, location updating, handovers, and call routing to a roaming

subscriber. These services are provided in conjunction with several functional entities,

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which together form the Network Subsystem. The MSC provides the connection to the

fixed networks (such as the PSTN or ISDN). Signaling between functional entities in the

Network Subsystem uses Signaling System Number 7 (SS7), used for trunk signaling in

ISDN and widely used in current public networks.

The Home Location Register (HLR) and Visitor Location Register (VLR), together with

the MSC, provide the call-routing and roaming capabilities of GSM. The HLR contains

all the administrative information of each subscriber registered in the corresponding

GSM network, along with the current location of the mobile. The location of the mobile

is typically in the form of the signaling address of the VLR associated with the mobile as

a distributed database. Station. The actual routing procedure will be described later.

There is logically one HLR per GSM network, although it may be implemented

The Visitor Location Register (VLR) contains selected administrative information from

the HLR, necessary for call control and provision of the subscribed services, for each

mobile currently located in the geographical area controlled by the VLR. Although each

functional entity can be implemented as an independent unit, all manufacturers of

switching equipment to date implement the VLR together with the MSC, so that the

geographical area controlled by the MSC corresponds to that controlled by the VLR, thus

simplifying the signaling required. Note that the MSC contains no information about

particular mobile stations --- this information is stored in the location registers.

CO SENSOR

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FEATURES:

* High sensitivity to carbon monoxide

* Stable and long life

APPLICATION:

They are used in gas detecting equipment for carbon monoxide (CO) in family and

Industry or car.

SPECIFICATIONS:

A. Standard work condition

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OPERATION PRINCIPLE:

The surface resistance of the sensor Rs is obtained through effected voltage signal output

of the load resistance RL which series-wound. The relationship between them is

described:

Rs\RL = (Vc-VRL) / VRL

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shows alterable situation of RL signal output measured by using Fig. 2 circuit

output signal when the sensor is shifted from clean air to carbon monoxide (CO) , output

signal measurement is made within one or two complete heating period (2.5 minute from

high voltage to low voltage). Sensitive layer of MQ-7 gas sensitive components is made

of SnO2 with stability, So it has excellent long term stability. Its service life can reach 5

years under using condition.

SENSITVITY ADJUSTMENT

Resistance value of MQ-7 is difference to various kinds and various concentration

gases. So, When using this components, sensitivity adjustment is very necessary. we

recommend that you calibrate the detector for 200ppm CO in air and use value of Load

resistance that( RL) about 10 KΩ(5KΩ to 47 KΩ). When accurately measuring, the

proper alarm point for the gas detector should be determined after considering the

temperature and humidity influence. The sensitivity adjusting program:

a. Connect the sensor to the application circuit.

b. Turn on the power, keep preheating through electricity over 48 hours.

c. Adjust the load resistance RL until you get a signal value which is respond to a certain

Carbon monoxide concentration at the end point of 90 seconds.

d. Adjust the another load resistance RL until you get a signal value which is respond to a

CO concentration at the end point of 60 seconds .

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MAX-232:

Meet or Exceed TIA/EIA-232-F and ITU

Recommendation V.28

Operate With Single 5-V Power Supply

Operate Up to 120 kbit/s

Two Drivers and Two Receivers

30-V Input Levels

Low Supply Current . . . 8 mA Typical

Designed to be Interchangeable With Maxim MAX232

ESD Protection Exceeds JESD 22

2000-V Human-Body Model (A114-A)

Applications:

TIA/EIA-232-F

Battery-Powered Systems

Terminals

Modems

Computers

Description/ordering information:

The MAX232 is a dual driver/receiver that includes a capacitive voltage generator

to supply EIA-232 voltage levels from a single 5-V supply. Each receiver converts EIA-

232 inputs to 5-V TTL/CMOS levels. These receivers have a typical threshold of 1.3 V

and a typical hysteresis of 0.5 V, and can accept 30-V inputs. Each driver converts

TTL/CMOS input levels into EIA-232 levels. The driver, receiver, and voltage-generator

functions are available as cells in the Texas Instruments Lin ASIClibrary.

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Fig.12:Pin diagram of Max-232

Power supply:

The power supplies are designed to convert high voltage AC mains electricity to a

suitable low voltage supply for electronics circuits and other devices. A power supply can

31S.R.T.I.S.T-ECE


by broken down into a series of blocks, each of which performs a particular function. A

d.c power supply which maintains the output voltage constant irrespective of a.c mains

fluctuations or load variations is known as “Regulated D.C Power Supply”

For example a 5V regulated power supply system as shown below:

Fig.13: power supply

8. Circuit Description

In the above project discussed as far, we are not sure about actually the idea

regarding the project because , till now we had discussed about the different components

used in the project and their specifications, characteristics etc. but now we come across

32S.R.T.I.S.T-ECE


the flow of data or the sequence of the connections regarding these components with the

microcontroller.

In this flow the place goes to the power supply circuit and which is also used any

application where ever the controller is necessary. That means power supply plays a

major role in any project. It is easy and simple either to built or learn. When the question

comes, “what are the major components used in the circuit ……?” Immediately the

answer is “It consists of four important components such as

- A transformer which is step down

- A rectifier bridge.

- A Electrolytic Capacitor and

- The voltage regulator”

The total operation and the action of the power supply circuit as already discussed

earlier.

Here in this project we are using five different sensors as inputs for the maximum

data inputs such as

- CO sensor

As these all are made with analog in the name of data and the controller accepts

only the data which is in digital form we are using another component for converting

from analog data to the digital data and called as the analog to digital converter (ADC).

So, now the output of the ADC is in digital and was made to send to the controller. The

controller analysis the data according to the program written by the designer and forward

to the GSM modem. Actually here the data in the sense the output of the sensors. The

sensor gives output when the respective physical quantity crosses the set point that

indicates the pre disaster and they are mean to display in another place

. To make a display we are using GSM communication, the data from the

controller is forwarded to the modem through MAX232. for this communication of data

we have to under go a big process called a serial communication. For the serial com to be

a successful process we need two mediators in between such as MAX232 and the RS232.

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MAX is a 16 pin IC which is also called as a level converter, which means the voltage

levels of the controller are converted to the PC voltage levels and vise versa. RS232 is a

recommended standard cable used for the wire connection between the max and the GSM

modem. After all process the data is sent to our registered mobile number in the form of

SMS by the modem.

9.source code

#include <REGX51.H> sbit rs=P3^7; //P3^7; 4th pin of LCD RSsbit rw=P3^6; // P3^6; 5th pin of LCD R/Wsbit en=P3^5; // P3^5; 6th pin of LCD E

Void lcd_cmd(unsigned char);Void lcd_data(unsigned char);void lcd_string(char *s);void Delay_ms(unsigned int x);void lcd_init();

void init_serial_port (); void str_tx(unsigned char *p); void tx(unsigned char val); void SEND_GSM(unsigned char *msg,unsigned char *mno); sbit smoke=P1^0; sbit dc=P1^1; void main(){ lcd_init(); init_serial_port(); lcd_cmd(0x80); //first line first pos Delay_ms(5); lcd_string(" WELCOME "); Delay_ms(5); while(1){ if(smoke==0){ lcd_cmd(0x80);

lcd_string(" Sending SMS.... "); Delay_ms(30); SEND_GSM("SMOKE DETECTED","9550140850");

lcd_cmd(0x80);

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lcd_string(" Message Sent ");Delay_ms(50);

dc=1; } else if(smoke==1){ lcd_cmd(0x80);

lcd_string("NO SMOKE DETECTED "); Delay_ms(5);

dc=0; } }}void SEND_GSM(unsigned char *msg,unsigned char *mno){ str_tx("AT+CMGS=\""); // ( AT+CMGS=" ) will be sendstr_tx(mno); //

// " Delay_ms(10); str_tx(msg); // message tx(0x1a); // Ascii Code of the CTRL+Z tx(0x0d); // Ascii Code of the Enter Key Delay_ms(10); }void lcd_init(){ lcd_cmd(0x38);

Delay_ms(5);lcd_cmd(0x0C);Delay_ms(5);lcd_cmd(0x01);Delay_ms(5);lcd_cmd(0x06);Delay_ms(5);lcd_cmd(0x80);Delay_ms(5);

}void lcd_cmd(unsigned char value){

P2=value;rs = 0;rw = 0;en = 1;Delay_ms(20);en = 0;return;

}void lcd_data(unsigned char value){

P2=value;rs = 1;

35S.R.T.I.S.T-ECE


rw = 0;en = 1;Delay_ms(20);en = 0;return;

}void lcd_string(char *s){ while(*s)

lcd_data(*s++);Delay_ms(10);

} void Delay_ms(unsigned int x) { unsigned int i,j;

for(i=0;i<x;i++)for(j=0;j<1275;j++); /// unsigned int y;

/// for(y=0;y<=x;y++); }

10. Software Components

a. About Keil:

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1. Click on the Keil u Vision Icon on Desktop

2. The following fig will appear

3. Click on the Project menu from the title bar

4. Then Click on New Project

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5. Save the Project by typing suitable project name with no extension in u r own folder sited in either C:\ or D:\

6. Then Click on Save button above.

7. Select the component for u r project. i.e. Atmel……

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8. Click on the + Symbol beside of Atmel

9. Select AT89C51 as shown below

10. Then Click on “OK”

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11. The Following fig will appear

12. Then Click either YES or NO………mostly “NO”

13. Now your project is ready to USE

14. Now double click on the Target1, you would get another option “Source

group 1” as shown in next page.

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15. Click on the file option from menu bar and select “new”

16. The next screen will be as shown in next page, and just maximize it by double

clicking on its blue boarder.

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17. Now start writing program in either in “C” or “ASM”

18. For a program written in Assembly, then save it with extension “. asm” and

for “C” based program save it with extension “ .C”

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19. Now right click on Source group 1 and click on “Add files to Group Source”

20. Now you will get another window, on which by default “C” files will appear.

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21. Now select as per your file extension given while saving the file

22. Click only one time on option “ADD”

23. Now Press function key F7 to compile. Any error will appear if so happen.

24. If the file contains no error, then press Control+F5 simultaneously.

25. The new window is as follows

44S.R.T.I.S.T-ECE


25.Then Click “OK”

26. Now Click on the Peripherals from menu bar, and check your required port as

shown in fig below

27. Drag the port a side and click in the program file.

45S.R.T.I.S.T-ECE


28. Now keep Pressing function key “F11” slowly and observe.

29. You are running your program successfully

b. Embedded C:

Data Types:

U people have already come across the word “Data types” in C- Language. Here

also the functionality and the meaning of the word is same except a small change in the

prefix of their labels. Now we will discuss some of the widely used data types for

embedded C- programming.

Data Types Size in Bits Data Range/Usage

unsigned char 8-bit 0-255

signed char 8-bit -128 to +127

unsigned int 16-bit 0 to 65535

signed int 16-bit -32,768 to +32,767

sbit 1-bit SFR bit addressable only

Bit 1-bit RAM bit addressable only

Sfr 8-bit RAM addresses 80-FFH

only

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Unsigned char:

The unsigned char is an 8-bit data type that takes a value in the range of 0-255(00-

FFH). It is used in many situations, such as setting a counter value, where there is no

need for signed data we should use the unsigned char instead of the signed char.

Remember that C compilers use the signed char as the default if we do not put the key

word

Signed char:

The signed char is an 8-bit data type that uses the most significant bit (D7 of D7-

D0) to represent the – or + values. As a result, we have only 7 bits for the magnitude of

the signed number, giving us values from -128 to +127. In situations where + and – are

needed to represent a given quantity such as temperature, the use of the signed char data

type is a must.

Unsigned int:

The unsigned int is a 16-bit data type that takes a value in the range of 0 to 65535

(0000-FFFFH). It is also used to set counter values of more than 256. We must use the int

data type unless we have to. Since registers and memory are in 8-bit chunks, the misuse

of int variables will result in a larger hex file. To overcome this we can use the unsigned

char in place of unsigned.

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10. Conclusion

The project “A VEHICULAR WIRELESS SENSOR NETWORK FOR

VEHICLE EMISSIONS MONITORING” has been successfully designed and tested.

It has been developed by integrating features of all the hardware

components used. Presence of every module has been reasoned out and placed carefully

thus contributing to the best working of the unit.

Secondly, using highly advanced IC’s and with the help of growing technology the

project has been successfully implemented.

Finally we conclude that “ A VEHICULAR WIRELESS

SENSOR NETWORK FOR VEHICLE EMISSIONS MONITORING” is an emerging

field and there is a huge scope for research and development.

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11. FUTURE ENHANCEMENT

In this project “A VEHICULAR WIRELESS SENSOR NETWORK FOR

VEHICLE EMISSIONS MONITORING can be further modified by controlling the

equipments which we are monitoring regarding the disaster of that equipment by proper

measurements.

The controlling part can also be done by the same mobile keypad. When we dial a

number from that mobile the particular signal is passed to the dialed mobile and we can

control this system. So, here we can do the monitoring part and also the controlling part

by a little modification.

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12. Bibliography

The 8051 Micro controller and Embedded Systems -Muhammad Ali Mazidi Janice Gillispie Mazidi

The 8051 Micro controller Architecture, Programming & Applications

-Kenneth J.Ayala

Fundamentals of Micro processors and Micro computers

-B.Ram

Micro processor Architecture, Programming & Applications

-Ramesh S. Gaonkar

Electronic Components

-D.V. Prasad

Wireless Communications - Theodore S. Rappaport

Mobile Tele Communications - William C.Y. Lee

References on the Web:

www.national.comwww.atmel.comwww.microsoftsearch.comwww.geocities.com

50S.R.T.I.S.T-ECE

http://www.geocities.com/

http://www.microsoftsearch.com/

http://www.atmel.com/

http://www.national.com/

Documents

A Vehicular Wireless Sensor Network for Vehicle Emissions Monitoring