vtu final report draft for project on smart car parking security system

7/29/2019 Vtu Final Report Draft for project on smart car parking security system

1/56

CELL SITE MONITORING 2009-2010

DEPT OF T.E, VIT, BANGALORE Page 1

ABSTRACT

Mobile communication is made possible by sending and receiving various signals between

mobiles and cell sites. Due to high traffic, there are many cell sites which have their own

equipment. Hence constant monitoring of these equipments becomes a tedious job.

The goal of this project is to design an embedded device which is used to monitor and

control the equipment in the GSM cell site remotely with the help of GSM modem and

mobile phone.

To implement this, a programmed microcontroller is connected to a GSM modem which

would send a SMS at regular intervals of time to the concerned operator. This system

continuously monitors the parameters affecting the functioning of cell site like voltage,

temperature, fuel consumption and the results of this processing is sent through SMS to the

concerned operator. The microcontroller which is connected to the modem using serial

communication through RS232 can be used for transmission of measured parameters.

Field based service engineers and plant managers can receive and access real-time data from

the plant via mobile phones or GSM modems virtually anywhere in the world. This also

means that remote sites in areas where there are no reliable landlines can be monitored.

The systems can be configured to send SMS (Short Message Service) mobile text messages,

highlighting changes in plant status triggered by parameters moving outside preset limits.These may simply be to warn that product is running low in a particular silo or to highlight

more serious operational problems.


2/56




3/56



CHAPTER 1

INTRODUCTION

1.1 DESCRIPTION

Global System for Mobile communication (GSM) was formally initiated by European

commission in the form of a directive in 1987. The system chosen used digital

technology and became known as GSM cellular system.

GSM technology has become the most popular cellular telephone technology with

approximately 72% of worlds cellular customers subscribing to the services. GSM

technology uses TDMA to allow up to 8 users per channel. Channels are spaced 20 0 kHz

apart. The basic system uses frequencies in the 900 MHz band (GSM 900). The up

banded version of GSM 900 is at 1800 MHz (GSM 1800) and the US uses 1900 MHz

(GSM 1900) for PCS service. GSM service when first introduced supported circuits

switched data rates of up to 9.6 k Bps.

1.2 CELL SITE

1.2.1 WHAT ARE CELL SITES?

A cell site, otherwise known as a mobile phone base station is a low power radio transmitter

with an antenna to transmit radio waves to mobile phones. Often distinguished by tall masts

because radio waves travel in straight lines and can be interrupted or deflected by buildings

or terrain. It is the location where the wireless antenna and network communications

equipment is placed. A cell site consists of a transmitter/receiver, antenna tower,

transmission radios and radio controllers. A cell site is operated by a Wireless Service

Provider (WSP). A synonym for "cell site" is "cell tower", although many cell site antennas

are mounted on buildings rather than as towers. In GSM networks, the technically correct

term is Base Transceiver Station (BTS), and colloquial British English synonyms are "mobile
http://www.o2.com/cr/what_are_radio_waves.asphttp://en.wikipedia.org/wiki/Base_Transceiver_Stationhttp://en.wikipedia.org/wiki/British_Englishhttp://en.wikipedia.org/wiki/British_Englishhttp://en.wikipedia.org/wiki/Base_Transceiver_Stationhttp://www.o2.com/cr/what_are_radio_waves.asp


4/56



phone mast" or "base station". The term "base station site" might better reflect the increasing

co-location of multiple mobile operators, and therefore multiple base stations, at a single site.

Depending on an operator's technology, even a site hosting just a single mobile operator may

house multiple base stations, each to serve a different air interface technology (CDMA or

GSM, for example). Preserved trees capes can often hide cell towers inside an artificial tree

or preserved tree. These installations are generally referred to as concealed cell sites or

stealth cell sites.

1.2.2 RANGE

The working range of a cell site - the range within which mobile devices can connect to it

reliably is not a fixed figure. It will depend on a number of factors, including

The frequency of signal in use (i.e. the underlying technology). The transmitters rated power. The transmitter's size.
http://en.wikipedia.org/wiki/Base_stationhttp://en.wikipedia.org/wiki/CDMAhttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/CDMAhttp://en.wikipedia.org/wiki/Base_station


5/56



The array setup of panels may cause the transmitter to be directional or Omni-directional.

It may also be limited by local geographical or regulatory factors and weather conditions.

Generally, in areas where there are enough cell sites to cover a wide area, the range of each

one will be set to:

Ensure there is enough overlap for "handover" to/from other sites (moving the signal for amobile device from one cell site to another, for those technologies that can handle it - e.g.

making a GSM phone call while in a car or train).

Ensure that the overlap area is not too large, to minimize interference problems with othersites.

1.2.3 COST AND POWER USE-

A conventional base station costs about $100,000 and uses 3000 watts of power. New, more

efficient ones cost around $15,000 and use 100 watts of power.

1.2.4 TEMPORARY SET-UP
http://en.wikipedia.org/wiki/Directional_antennahttp://en.wikipedia.org/wiki/Omnidirectional_antennahttp://en.wikipedia.org/wiki/File:Cell_on_wheels.jpghttp://en.wikipedia.org/wiki/Omnidirectional_antennahttp://en.wikipedia.org/wiki/Directional_antenna


6/56



Although cell antennas are normally attached to permanent structures, cell providers maintain

a fleet of temporary cell sites. When mounted on a trailer, they are called a COW or Cell on

Wheels. These usually include a base station controller and a telescoping tower with antennas

attached. A generator may be included when electrical power isn't available, and an

additional backhaul antenna may be mounted to link the temporary tower into the network.

COWs are often used at the site of a permanent cell site. Floods, fires, terrorism, and other

disasters may destroy permanent antennas or base stations controllers, and fast dispatch of

COWs can maintain vital communications during an emergency. They are also used in

planned outages, such as when an antenna site is unavailable due to construction or

maintenance. Finally, they are often used to augment capacity when large numbers of

additional cell phone users are expected, such as at large sporting events.

1.2.5 EMERGENCY POWER-

Fuel cell backup power systems are added to critical cell sites or base stations to provide

emergency power. In reality though, few cell sites use fuel cells and use internal combustion

engine driven generator set.

1.2.6 TYPES OF CELLS-

A macro cell provides the largest area of coverage within a mobile network. Its antennas can

be mounted on ground-based masts, rooftops or other structures and must be high enough to

avoid obstruction. Macro cells provide radio coverage over varying distances, depending onthe frequency used, the number of calls and the physical terrain. Typically they have a power

output in tens of watts.
http://en.wikipedia.org/wiki/Cell_On_Wheelshttp://en.wikipedia.org/wiki/Cell_On_Wheelshttp://en.wikipedia.org/wiki/Backhaul_(telecommunications)http://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Backup_powerhttp://en.wikipedia.org/wiki/Base_stationshttp://en.wikipedia.org/wiki/Base_stationshttp://en.wikipedia.org/wiki/Backup_powerhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Backhaul_(telecommunications)http://en.wikipedia.org/wiki/Cell_On_Wheelshttp://en.wikipedia.org/wiki/Cell_On_Wheels


7/56



Microcells provide additional coverage and capacity in areas where there are high numbers

of users, urban and suburban areas, for example. The antennas for microcells are mounted at

street level, are smaller than macro cell antennas and can often be disguised as building

features so that they are less visually intrusive. Microcells provide radio coverage over

distances typically between 300m and 1000m and have lower output powers than

marocells, usually a few watts.

Pico cells provide more localized coverage. These are generally found inside buildings where

coverage is poor or where there is a dense population of users such as in airport terminals,

train stations and shopping centers.

Femtocell base stations allow mobile phone users to make calls inside their homes via their

Internet broadband connection. Femto-cells provide small area coverage solutions operating

at low transmit powers.


8/56



1.3 BLOCK DIAGRAM

Block Diagram

Microcontroller

Voltage Sensor

AC input

MUX/ADC

Fuellevel

sensor

Temperature

sensor

Memory

Power Supply

GSM

Modem

GSM

Modem

Data processing using C

RS232

PC

To all

components

The block diagram consist following section

1.Sensors

2.ADC

3.Microcontroller

4.GSM modem

5.PC


9/56



1.3.1 MICROCONTROLLER SECTION

A Microcontroller is memory oriented architecture. Any microcontroller basically has a

microprocessor with limited number of RAM, ROM, I/O ports and timer on a single

chip. All the required hardware for a system is combined together on a single chip.

Being a built-in-chip, it occupies less space, draws less current, and is cheaper. It has the

specified computational capabilities and enhanced I/O operation capabilities.

1.3.2 GSM MODEM SECTION

A GSM modem is a specialized type of modem which accepts a SIM card, and operates

over a subscription to a mobile operator, just like a mobile phone. A GSM modem can

be a dedicated modem device with a serial, USB or Bluetooth connection, or it may be a

mobile phone that provides GSM modem capabilities. GSM modems can be a quick and

efficient way to get started with SMS, because a special subscription to an SMS service

provider is not required. The mobile operator charges for this message sending and

receiving as if it was performed directly on a mobile phone. In most parts of the world,

GSM modems are a cost effective solution for receiving SMS messages, because the

sender is paying for the message delivery.

1.3.3 ADC SECTION

ADC (analog to digital converters) is among the most widely used devices for data

acquisition. Digital computers use binary (discrete) values, but in the physical world

everything is analog (continuous). Temperature, pressure (wind or liquid), humidity, and

velocity are a few examples of physical quantities that we deal with everyday. A

physical quantity is converted to electrical (voltage, current) signals using a device

called a transducer. Transducers are also referred to as sensors. Sensors for temperature,

velocity, pressure, light and many other natural quantities produce an output that is

voltage (or current). Therefore, we need an ADC to translate the analog signals to digital

numbers so that the microcontroller can read and process them.


10/56



CHAPTER 3

TRANSMITER SECTION

TEMPERATURE SENSORS LM35

3.1 GENERAL DESCRIPTION

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage

is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an

advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to

subtract a large constant voltage from its output to obtain convenient Centigrade scaling. The

LM35 does not require any external calibration or trimming to provide typical accuracies of14C at room temperature and 34C over a full 55 to +150C temperature range. The

LM35s low output impedance, linear output, and precise inherent calibration make

interfacing to readout or control circuitry especially easy. It can be used with single power

supplies, or with plus and minus supplies. As it draws only 60 A from its supply, it has very

low self-heating, less than 0.1C in still air. The LM35 is rated to operate over a 55 to

+150C temperature range.

3.2 FEATURES

Calibrated directly in Celsius (Centigrade) Linear + 10.0 mV/C scale factor 0.5C accuracy guarantee able (at +25C) Rated for full 55 to +150C range Suitable for remote applications Operates from 4 to 30 volts Less than 60 A current drain Low self-heating, 0.08C in still air Nonlinearity only 14C typical Low impedance output, 0.1 W for 1 mA load


11/56



3.3 BASIC BLOCK DIAGRAM

Fig 1: Basic centigrade temperature sensor

(+2C to +150C)

Fig 2: Full range centigrade temperature sensor


12/56



Structure of LM35 temperature sensor

3.4 APPLICATION

The LM35 can be applied easily in the same way as other integrated-circuit temperature

sensors. It can be glued or cemented to a surface and its temperature will be within about

0.01C of the surface temperature. This presumes that the ambient air temperature is almost

the same as the surface temperature; if the air temperature were much higher or lower than

the surface temperature, the actual temperature of the LM35 die would be at an intermediate

temperature between the surface temperature and the air temperature. This is especially true

for the TO-92 plastic package, where the copper leads are the principal thermal path to carry

heat into the device, so its temperature might be closer to the air temperature than to the

surface temperature. To minimize this problem, be sure that the wiring to the LM35, as it

leaves the device, is held at the same temperature as the surface of interest.

3.5 ADC 0808

3.5.1 FEATURES

Easy interface to all microprocessors Operates ratio metrically or with 5 VDC or analog span adjusted voltage reference No zero or full-scale adjust required


13/56



8-channel multiplexer with address logic 0V to 5V input range with single 5V power supply Outputs meet TTL voltage level specifications Standard hermetic or molded 28-pin DIP package 28-pin molded chip carrier package ADC0808 equivalent to MM74C949 ADC0809 equivalent to MM74C949-1

3.5.2 KEY SPECIFICATIONS

Resolution 8 Bits Total Unadjusted Error 12 LSB and 1 LSB Single Supply 5 VDC Low Power 15 mW Conversion Time 100 s

3.5.3GENERAL DESCRIPTION

The ADC0808, ADC0809 data acquisition component is a monolithic CMOS device with an

8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor compatible

control logic. The 8-bit A/D converter uses successive approximation as the conversion

technique. The converter features a high impedance chopper stabilized comparator, a 256R

voltage divider with analog switch tree and a successive approximation register. The 8-

channel multiplexer can directly access any of 8-single-ended analog signals. The deviceeliminates the need for external zero and full-scale adjustments. Easy interfacing to

microprocessors is provided by the latched and decoded multiplexer address inputs and

latched TTL TRI-STATE outputs.


14/56



The design of the ADC0808, ADC0809 has been optimized by incorporating the most

desirable aspects of several A/D conversion techniques. The ADC0808, ADC0809 offers

high speed, high accuracy, minimal temperature dependence, excellent long-term accuracy

and repeatability, and consumes minimal power. These features make this device ideally

suited to applications from process and machine control to consumer and automotive

applications.

3.5.4 PIN DIAGRAM

3.5.5 FUNCTIONAL DESCRIPTION

The device contains an 8-channel single-ended analog signal multiplexer. A particular input

channel is selected by using the address decoder. Table 1 shows the input States for the

address lines to select any channel. The address is latched into the decoder on the low-to-high

transition of the address latch enable signal.


15/56



TABLE 3.1

SELECTED ADDRESS LINE ANALOG CHANNEL

C B A

IN0 L L L

IN1 L L H

IN2 L H L

IN3 L H H

IN4 H L L

IN5 H L H

IN6 H H L

IN7 H H H

3.6 7805 VOLTAGE REGULATOR

This is most common voltage regulator that is still used in embedded designs. LM7805

voltage regulator is a linear regulator made by several manufacturers like Fairchild, or ST

Microelectronics. They can come in several types of packages. For output current up to 1A

there may be two types of packages: TO-220 (vertical) and D-PAK (horizontal).

With proper heat sink these LM78xx types can handle even more than 1A current. They also

have Thermal overload protection, Short circuit protection.
http://www.scienceprog.com/7805-voltage-regulator-for-your-design/http://www.scienceprog.com/7805-voltage-regulator-for-your-design/


16/56



Typical Connection is very simple:

Couples decoupling capacitors (between 10 of and 47 uF) are required on the input (V-IN)

and output (V-OUT) connected to ground.

There are negative voltage regulators that work the same way. They are marked as LM79xx.


17/56



CHAPTER 4

MICROCONTROLLER SECTION

4.1 FEATURES

4K Bytes of In-System Programmable (ISP) Flash Memory

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

128 x 8-bit Internal RAM

32 Programmable I/O Lines

Two 16-bit Timer/Counters

Full Duplex UART Serial Channel

Low-power Idle and Power-down Modes

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)


18/56



4.2 DESCRIPTION

The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes

of in-system programmable Flash memory. The device is manufactured using Atmels high-

density nonvolatile memory technology and is compatible with the industry- standard 80C51

instruction set and pin out. The on-chip Flash allows the program memory to be

reprogrammed in-system or by a conventional nonvolatile memory programmer. By

combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip,

the Atmel AT89S51 is a powerful microcontroller which provides a highly-flexible and cost-

effective solution to many embedded control applications.

The AT89S51 provides the following standard features: 4K bytes of Flash, 128 bytes of

RAM, 32 I/O lines, Watchdog timer, two data pointers, two 16-bit timer/counters, a five-

vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock

circuitry. In addition, the AT89S51 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 external interrupt or hardware

reset.


19/56



4.3 8-BIT MICROCONTROLLER WITH 4K BYTES IN-SYSTEM

PROGRAMMABLE FLASH

Pin Description

VCC

Supply voltage.

GND

Ground.


20/56



Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight

TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance

inputs.

Port 0 can also be configured to be the multiplexed low-order address/data bus during

accesses to external program and data memory. In this mode, P0 has internal pull-ups.

Port 0 also receives the code bytes during Flash programming and outputs the code bytes

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

Port 1

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

sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the

internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. Port 1 also receives the

low-order address bytes during Flash programming and verification.

Port Pin Alternate Functions

P1.5 MOSI (used for In-System Programming)

P1.6 MISO (used for In-System Programming)

P1.7 SCK (used for In-System Programming)

Port 2




21/56




pulled low will source current (IIL) because of the internal pull-ups.

Port 2 emits the high-order address byte during fetches from external program memory and

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

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

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

the P2 Special Function Register. Port 2 also receives the high-order address bits and some

control signals during Flash programming and verification.

Port 3




pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control

signals for Flash programming and verification. Port 3 also serves the functions of various

special features of the AT89S51, as shown in the figure.

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)


22/56



P3.5 T1 (timer 1 external input)

P3.6 WR (external data memory write strobe)

P3.7 RD (external data memory read strobe)

RST Reset input.

A high on this pin for two machine cycles while the oscillator is running resets the device.

This pin drives High for 98 oscillator periods after the Watchdog times out. The DISRTO bit

in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit

DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG

Address Latch Enable (ALE) is an output pulse for latching the low byte of the address

during accesses to external memory. This pin is also the program pulse input (PROG) during

Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the

oscillator frequency and may be used for external timing or clocking purposes. Note,

however, that one ALE pulse is skipped during each access to external data memory. If

desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit

set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly

pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external

execution mode.

PSEN

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

AT89S51 is executing code from external program memory, PSEN is activated twice each


23/56



machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA/VPP External Access Enable

EA must be strapped to GND in order to enable the device to fetch code from external

program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1

is programmed, EA will be internally latched on reset. EA should be strapped to VCC for

internal program executions. This pin also receives the 12-volt programming enable voltage

(VPP) during Flash programming.

XTAL1

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

XTAL2

Output from the inverting oscillator amplifier


24/56


25/56



Name (V24) 9pin Dir Full name Remarks

-----------------------------------------------------------

TxD 3 o Transmit Data

RxD 2 i Receive Data

RTS 7 o Request To Send

CTS 8 i Clear To Send

DTR 4 o Data Terminal Ready

DSR 6 i Data Set Ready

RI 9 i Ring Indicator

DCD 1 i Data Carrier Detect

GND 5 - Signal ground

4.4.3 TRANSMITTED SIGNAL

VOLTAGE LEVELS:

Binary 0: +5 to +15 Vdc

(called a space or on)

Binary 1: -5 to -15 Vdc

(called a mark or off)


26/56



RECEIVED SIGNAL

VOLTAGE LEVELS:

Binary 0: +3 to +13 Vdc

Binary 1: -3 to -13 Vdc

4.4 MAX232

When communicating with various micro processors one needs to convert the RS232 levels

down to lower levels, typically 3.3 or 5.0 Volts. Serial RS-232 communication works with

voltages -15V to +15V for high and low. On the other hand , TTL logic operates between 0Vand +5V. Modern low power consumption logic operates in the range of 0V and +3.3V or

even lower.

Thus the RS-232 signal levels are far too high TTL electronics, and the negative RS-232

voltage for high cant be handled by computer logic. To receive serial data from an RS-232

interface the voltage has to be reduced. Also the low and high voltage level has to be

inverted.

The MAX232 converts from RS232 voltage levels to TTL levels and vice versa. The

MAX232 chip uses a 5V power source which is as same as the microcontroller. Hence there

is no need for dual power supply.

The MAX232 has two sets of drivers for transferring and receiving. The line drivers used for

TxD are called T1 and T2, while the line driver used for RxD are designated as R1 and

RS-232 TTL Logic

-15V -3V +2V +5V High

+3V +15V 0V +0.8V Low
http://sodoityourself.com/max232-serial-level-converter/http://sodoityourself.com/max232-serial-level-converter/http://sodoityourself.com/max232-serial-level-converter/http://sodoityourself.com/max232-serial-level-converter/


27/56



R2.The T1in pin is the TTL side and is connected to TxD of microcontroller, while T1out is

the pin connected to RS232 side that is connected to RxD pin. R1in is the RS232 side that is

connected to TxD pin of RS232 DB connector and R1out is the TTL side connected to RxD

pin of the microcontroller.


28/56



CHAPTER 5

GSM (Global System for Mobile communication)

5.1 HISTORY OF GSM

During the early 1980s, analog cellular telephone systems were experiencing rapid growth in

Europe, particularly in Scandinavia and the United Kingdom, but also in France and

Germany. Each country developed its own system, which was incompatible with everyone

else's in equipment and operation. This was an undesirable situation, because not only was

the mobile equipment limited to operation within national boundaries, which in a unified

Europe were increasingly unimportant, but there was also a very limited market for each type

of equipment, so economies of scale and the subsequent savings could not be realized.

The Europeans realized this early on, and in 1982 the Conference of European Posts and

Telegraphs (CEPT) formed a study group called the Grouped Special Mobile (GSM) to study

and develop a pan-European public land mobile system. The proposed system had to meet

certain criteria:

Good subjective speech quality Low terminal and service cost Support for international roaming Ability to support handheld terminals Support for range of new services and facilities Spectral efficiency ISDN compatibility

In 1989, GSM responsibility was transferred to the European Telecommunication Standards

Institute (ETSI), and phase I of the GSM specifications were published in 1990. Commercial

service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries.

Although standardized in Europe, GSM is not only a European standard. Over 200 GSM


29/56



networks (including DCS1800 and PCS1900) are operational in 110 countries around the

world. In the beginning of 1994, there were 1.3 million subscribers worldwide, which had

grown to more than 55 million by October 1997. With North America making a delayed

entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on

every continent, and the acronym GSM now aptly stands for Global System for Mobile

communications.

The developers of GSM chose an unproven (at the time) digital system, as opposed to the

then-standard analog cellular systems like AMPS in the United States and TACS in the

United Kingdom. They had faith that advancements in compression algorithms and digital

signal processors would allow the fulfillment of the original criteria and the continual

improvement of the system in terms of quality and cost. The over 8000 pages of GSM

recommendations try to allow flexibility and competitive innovation among suppliers, but

provide enough standardization to guarantee proper interworking between the components of

the system. This is done by providing functional and interface descriptions for each of the

functional entities defined in the system.

5.2ADVANTAGES OF GSM: GSM is more stable network with robust features. These have less signal disturbance inside the buildings. The availability ofsubscribers identity modules allows user to switch network and

handsets at will.

GSM covers vertically all parts of world. So, International roaming is not aproblem.

5.4 DISADVANTAGES OF GSM:

GSM has a fixed maximum cell site range of 35km which is imposed by technicallimitation.


30/56



5.5 APPLICATIONS:

One of the applications which can be considered by using GSM technology is

accessing control devices which can communicate with servers and security staff

through SMS messaging complete log of transaction is available at the head office.

5.6 GSM MODEMS

A GSM modem can be an external modem device, such as the Siemens MC35 or Wavecom

FASTRACK external modems. 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 Sierra Wireless Aircard 750.

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

software driver to connect to a serial port or USB port on your computer. Any phone that

supports the "extended AT command set" for sending/receiving SMS messages, as defined in

the ETSI GSM 07.05 Specification can be supported by the Now SMS/MMS Gateway.

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, most

GSM phones will only allow you to send MMS messgaes. This is because the mobile phone

automatically processes received MMS message notifications these messages, without

forwarding them via the modem interface. Similarly some mobile phones will not allow youto 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.)


31/56



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. If a Windows driver is not available for your modem, you can use either the

"Standard" or "Generic" 19200 bps modem driver that is built into windows. A benefit of

utilizing a Windows modem driver 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.

5.7 AT COMMANDS

AT commands are also known as Hayes AT commands. There are different views to

understand the meanings of "AT". AT commands (attention commands) are instructions used

to control a modem. Every command line starts with AT or at. That is why modem

commands are called AT commands. Some call it "Attention Telephone", whereas others

interpret it as "Attention Terminal" commands.

AT commands allow giving instructions to both mobile devices and ordinary landline

telephones. The commands are sent to the phone's modem, which can be a GSM modem or

PC modem. Different manufacturers may have different sets of AT commands. Fortunately,


32/56



many AT commands are the same. Mobile device manufacturers may also give attention to

operators to allow or not to allow some commands on phones.

AT commands can be used for operations that are usually done from the keypad, for instance

calling a number, sending, reading, or deleting an SMS, setting the SMSC number, looking

for a GPRS access point, reading and deleting phonebook data, reading the battery status,

reading the signal strength, and so on. When you want to make a PC-based application to

interface a mobile phone using USB, IR, or Bluetooth, these commands are needed to

communicate with mobile phones.

ATE Command echo (ver. 2)

Description: Determines if the DCE echoes characters received from the DTE during

command state and online command state.

Set command: ATE []

Read command: ATE? Displays the current setting.

Test command: ATE=? Shows if the command is supported.

Test command response: E: (list of supported s)

Parameter:


33/56



:

Description

0 DCE does not echo characters during command

state and online command state

1 DCE echoes characters during command state and

online command state. Default value

AT+CMGR Read message (ver. 2)

Description: Returns message with location value from preferred message

storage to the TE. Status of the message and entire message

data unit is returned. Ifstatus of the message is received unread,

status in the storage changes to received read.

Execution command: AT+CMGR=

Execution command response: +CMGR: ,[],

Test command: AT+CMGR=? Shows if the command is supported.


34/56



Parameters:

:

Description

0 Received unread message (new message)

1 Received read message

2 Stored unsent message. (Only applicable to SMs)

3 Stored sent message. (Only applicable to SMs)

16 Template message

Integer type in PDU mode (default 0), indicates the status of message in memory.

:

Description

Integer type Value in the range of location numbers supported by the

Associated memory

:

Description

String type manufacturing specific. Should be left empty but

not omitted, that is, commas should mark the place

where it should be.

:

Description

Integer type Value indicating in PDU mode (AT+CMGF=0), the

length of the actual TP data unit in octets. The RP


35/56



layer SMSC address octets are not counted in the length)

:

Description

Hexadecimal value In the case of SMS: GSM 04.11 SC address followed

by GSM 03.40 TPDU in hexadecimal format.

ME/TA converts each octet of TP data unit into two

IRA character long hexadecimal number, for example,

octet with integer value 42 is presented to TE

as two characters 2A (IRA 50 and 65).

: See AT+CPMS

AT+CPMS Preferred message storage (ver. 4)

Description: Set command selects memory storage , and

to be used for reading, writing, and so on. If chosen storage is not

appropriate for the ME (but is supported by the TA), final result code

+CMS ERROR: is returned.

Set command: AT+CPMS=[,[,]]

Set command

Response: +CPMS: ,,,,,


36/56



Read command: AT+CPMS? Displays the current ,,,

,,,,, values.

Test command: AT+CPMS=? Shows if the command is supported.

Test command

Response: +CPMS: (list of supported s), (list of supported s),

(list of supported s)

Parameters:

:

Description

string type Memory from which messages are read and

deleted (commands List Messages AT+CMGL,

Read Messages AT+CMGR and Delete Messages

AT+CMGD)

ME Phone message storage

SM SIM message storage

:

Description

string type Memory to which writing and sending operations

are made ( commands Send Message from


37/56



Storage AT+CMSS and Write Message to Memory

AT+CMGW)

ME Phone message storage


:

Description

string type Memory to which received SMs are preferred to be

stored (unless forwarded directly to terminal

equipment). Received CBMs (Cell Broadcast

Messages) are always stored in BM (Broadcast

Message storage) or some manufacturer specific

storage, unless directly forwarded to terminal

equipment

ME Phone message storage.


,,:

, , Description

Integer type Total number of messages currently in ,

and respectively


38/56



, , :

, , Description

Integer type Total number of messages that can be stored in

, and respectively


39/56



CHAPTER 6

RECEIVER SECTION

6.1 BLUETOOTH

Bluetooth is a high-speed, low-power microwave wireless link technology, designed to

connect phones, laptops, PDAs and other portable equipment together with little or no work

by the user. Bluetooth is the name for a short-range radio frequency (RF) technology that

operates at 2.4 GHz and is capable of transmitting voice and data. The effective range of

Bluetooth devices is 32 feet (10 meters). Bluetooth transfers data at the rate of 1 Mbps, which

is from three to eight times the average speed of parallel and serial ports, respectively. It is

also known as the IEEE 802.15 standards.

It was invented to get rid of wires. Bluetooth is more suited for connecting two point-to-point

devices, whereas Wi-Fi is an IEEE standard intended for networking.

Bluetooth can be used to wirelessly synchronize and transfer data among devices. Bluetooth

can be thought of as a cable replacement technology. Typical uses include automatically

synchronizing contact and calendar information among desktop, notebook and palmtop

computers without connecting cables. Bluetooth can also be used to access a network or theInternet with a notebook computer by connecting wirelessly to a cellular phone.

6.1.1 HOW BLUETOOTH WORKS?

When you usecomputers, entertainment systems or telephones, the various pieces and parts

of the systems make up a community of electronic devices. These devices communicate with

each other using a variety of wires, cables, radiosignals and infrared light beams, and an

even greater variety of connectors, plugs and protocols.
http://electronics.howstuffworks.com/pc.htmhttp://electronics.howstuffworks.com/pc.htmhttp://electronics.howstuffworks.com/home-theater.htmhttp://electronics.howstuffworks.com/telephone.htmhttp://electronics.howstuffworks.com/radio-spectrum.htmhttp://electronics.howstuffworks.com/radio-spectrum.htmhttp://electronics.howstuffworks.com/radio-spectrum.htmhttp://electronics.howstuffworks.com/telephone.htmhttp://electronics.howstuffworks.com/home-theater.htmhttp://electronics.howstuffworks.com/pc.htm


40/56



There are lots of different ways that electronic devices can connect to one another. For

example:

Component cables Electrical wires Ethernet cables Wi Fi

The art of connecting things is becoming more and more complex every day. We will look at

a method of connecting devices, called Bluetooth, that can streamline the process. A

Bluetooth connection is wireless and automatic, and it has a number of interesting features

that can simplify our daily lives.
http://electronics.howstuffworks.com/wireless-internet.htmhttp://electronics.howstuffworks.com/wireless-internet.htm


41/56



6.2 SHORT MESSAGE SERVICE

6.2.1 DESCRIPTION

The SMS message, as specified by the ETSI organization (documents GSM 03.40 and GSM

03.38), can be up to 160 characters long, where each character is 7 bits according to the 7-bit

default alphabet. Eight-bit messages (max 140 characters) are usually not viewable by the

phones as text messages; instead they are used for data in e.g. smart messaging (images and

ringing tones).

6.3 THE PDU FORMAT

There are two ways of sending and receiving SMS messages: by text mode and by PDU

(protocol description unit) mode. The text mode (unavailable on some phones) is just an

encoding of the bit stream represented by the PDU mode. Alphabets may differ and there are

several encoding alternatives when displaying an SMS message. The most common options

are "8859-1", "IRA" and "GSM". These are all set by the at-command AT+CSCS, when you

read the message in a computer application. If you read the message on your phone, the

phone will choose a proper encoding. An application capable of reading an incoming SMS

message can thus use text mode or PDU mode. If text mode is used, the application is bound

to the set of preset encoding options. If PDU mode is used, any encoding can be

implemented.

6.3.1 RECEIVING A MESSAGE IN THE PDU MODE

The PDU string contains not only the message, but also a lot of meta-information about the

sender, his SMS service center, the time stamp etc. It is all in the form of hexa-

decimal octets or decimal semi-octets. Let us take an example of the text message of

hellohello".
http://www.dreamfabric.com/sms/default_alphabet.htmlhttp://www.dreamfabric.com/sms/default_alphabet.htmlhttp://www.fastlogic.co.za/faq59.htmhttp://www.fastlogic.co.za/faq59.htmhttp://www.dreamfabric.com/sms/default_alphabet.htmlhttp://www.dreamfabric.com/sms/default_alphabet.html


42/56



In PDU mode the SMS looks like:

07917283010010F5040BC87238880900F10000993092516195800AE8329BFD4697D9EC3

7

This octet sequence consists of three parts: An initial octet indicating the length of the SMSC

information ("07"), the SMSC information itself ("917283010010F5"), and the

SMS_DELIVER part (specified by ETSI in GSM 03.40).

Octet(s) Description

07 Length of the SMSC information (in this case 7 octets)

91 Type-of-address of the SMSC

72 83 01 00 10 F5

Service center number (in decimal semi-octets). The length of the

phone number is odd (11), so a trailing F has been added to form

proper octets. The phone number of this service center is

"+27381000015"

04 First octet of this SMS-DELIVER message

0B Length of the sender number (0B hex = 11 dec)

C8 Type-of-address of the sender number

72 38 88 09 00 F1 Sender number (decimal semi-octets), with a trailing F

00 TP-PID. Protocol identifier

00 TP-DCS Data coding scheme

99 30 92 51 61 95 80 TP-SCTS. Time stamp (semi-octets)

0A TP-UDL. User data length, length of message

E8329BFD4697D9EC37 Message:"hellohello" 8-bit octets representing 7-bit data.

All the octets above are hexa-decimal 8-bit octets, except the Service center number, the

sender number and the timestamp; they are decimal semi-octets. The message part in the end

of the PDU string consists of hexa-decimal 8-bit octets, but these octets represent 7-bit data.

The semi-octets are decimal, and e.g. the sender number is obtained by performing internal
http://www.dreamfabric.com/sms/type_of_address.htmlhttp://www.dreamfabric.com/sms/pid.htmlhttp://www.dreamfabric.com/sms/dcs.htmlhttp://www.dreamfabric.com/sms/scts.htmlhttp://www.dreamfabric.com/sms/scts.htmlhttp://www.dreamfabric.com/sms/dcs.htmlhttp://www.dreamfabric.com/sms/pid.htmlhttp://www.dreamfabric.com/sms/type_of_address.html


43/56



swapping within the semi-octets from "72 38 88 09 00 F1" to "27 83 88 90 00 1F". The

length of the phone number is odd, so a proper octet sequence cannot be formed by this

number. This is the reason why the trailing F has been added. The time stamp, when parsed,

equals "99 03 29 15 16 59 08", where the 6 first characters represent date, the following 6

represents time, and the last two represents time-zone related to GMT.


44/56



CHAPTER 7

CIRCUIT IMPLEMENTATION

7.1 PCB FABRICATION

The PCB used the system is a single board PCB. All these components can be housed on the

PCB and there is no external circuitry required expect for the power supply. There is only

one component side so all the components can be viewed directly on one side. The integer

circuits (ICs) are fixed on IC bases. These bases are soldered first and then the ICs are fixed

on the bases. This is done to avoid damaging the ICs by directly heating them while

soldering.

The art work is the first step towards developing the PCB. For doing an art work the circuit

has to be understood first and step by step designed procedure is to be followed. The

important component should be taken care first such as the addresses/data lines of the

MICROCONTROLLER and EPROM. Such lines should all be placed on the same side of

the PCB. The power supply lines should be on the either side of the PCB preferably to avoid

any dangerous shorting while soldering.

After the artwork is done the PCB size is to be selected and the lines are drawn on to it

according to the art design. This is then printed on to the board using techniques such as

screen printing.

Now the holes have to be drilled at the right places to house the components in safe manner.

After the holes have been drilled, then a continuity check is done to detect any shorted or

open lines.


45/56



Now the PCB is ready to be soldered on. While soldering care should be taken to avoid any

shorting of lines or points since the pines on the ICs are placed very close to each other. The

ADC on the PCB is kept at one side to provide isolation. The ICs are fixed on to their bases

and after a last checking the power supply is given and the system is tested for proper

functions.


46/56



7.3 DESIGN OF PCB SCHEMATIC LAYOUT


47/56




48/56



7.4 WORKING AND IMPLEMENTATION

The input to the voltage sensor is the ac input. The voltage sensor is used to sense the voltage

of the system. The fuel level potentiometer sensor is used for sensing the fuel level in diesel

generator. The temperature sensor is used for sensing the temperature of the system. Theseparameters are monitored continuously and fed as input to ADC which are further

multiplexed and fed to the microcontroller for further processing. These values are stored in

the memory. The average of each of these parameters over a 10min period is calculated and

is fed to the GSM modem at the transmitter site, where it is modulated and then transmitted

over the air interface. At the receiver site, the antenna collects the data which is fed into the

GSM modem where it is demodulated. This demodulated data is then further processed in the

computer. Hence, the operator monitoring this cell site gets the information of the parameters

affecting the functioning of the system at regular intervals of time (1 hour).

At any point in the operation of this system, if the value of voltage exceeds a certain

threshold, an alarm is raised using the alarm module and an SMS is immediately sent to the

operator through the GSM modem so that the operator can take the necessary steps to prevent

mechanical failure of the system.

The power supply block at the cell site consists of the diesel generator and the battery

backup. Power to the system components is provided by the commercial supply. When this

supply goes down, the battery backup provides immediate power till the diesel generator gets

started after which the diesel generator powers the system till the commercial supply is

restored.


49/56




50/56




51/56




52/56




53/56



CONCLUSION

PRECAUTIONS

It should be taken care that the baud rate set initially should be changed to a lower value to(9600 baud) to communicate with the board. Because, there is bit error generated at higher

baud rates and may cause generation of faulty outputs. During the setup of the modem it

should be noted that to send TX_IN to be high for about 0.2 sec to get the modem started.

After inserting the SIM card wait for some time to initialize the SIM card. When the modemis ready the green LED on the modem starts blinking


54/56



APPLICATIONS

The following are the applications that can be accomplished using this system:

FUEL CONSUMPTION:

This is a cost effective method wherein the system periodically measures the fuel used by the

equipment, which helps in knowing the amount of fuel required by the generator for longer

durations. This helps in keeping a track of the fuel used, hence preventing misuse of fuel and

detection of leakage.

VOLTAGE MEASUREMENT:

The system voltage is constantly monitored over every 10 minute interval and the report of

the average over 1 hour is sent to the operator. If at any time there is a voltage fluctuation, an

alarm is raised and the operator gets the report through SMS.

TEMPERATURE VARIATION:

An optimum temperature should be maintained for effective functioning of the system. Any

unexpected variations in temperature are reported to the operator.


55/56



FUTURESCOPE

1. One advancement of remote monitoring system is ability to use wireless sensors in a cell

site. Sensors must be attached to each equipment that needs to be monitored. Previously

sensors were connected by wires to the monitoring system.

2. This system monitors and manages the critical elements of a remote cell site bringing

various data together to a central control module remotely via variety of protocols.

3. We can use a three phase supply for increasing the efficiency of the system.

4. We may propose a security alarm system along with a card identification program to

monitor access to the facility.

5. The fact that changes in status are high lightened when they happen means that effective

risk assessment can be made before serious problems arise.


56/56


BIBLIOGRAPHY

TEXT BOOKS

8051 Microcontroller and Embedded Systems Using Assembly and C by Mohammad AliMazidi , Janice Gillispie Mazidi , Rolin D. Mckinlay. -Chapter 3, Chapter 4, Chapter 5,

chapter 6.

Programming in C by Balaguruswamy

WEBSITES

http://developer.sonyericsson.com/getDocument.do?docId=65054 http://en.wikipedia.org/wiki/GSM http://www.camiresearch.com/Data_Com_Basics/RS232_standard .html http://www.gsm-modem.de/sms-text-mode.html www.atmel.com
http://developer.sonyericsson.com/getDocument.do?docId=65054http://developer.sonyericsson.com/getDocument.do?docId=65054http://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/GSMhttp://www.camiresearch.com/Data_Com_Basics/RS232_standard%20.htmlhttp://www.camiresearch.com/Data_Com_Basics/RS232_standard%20.htmlhttp://www.gsm-modem.de/sms-text-mode.htmlhttp://www.gsm-modem.de/sms-text-mode.htmlhttp://www.gsm-modem.de/sms-text-mode.htmlhttp://www.camiresearch.com/Data_Com_Basics/RS232_standard%20.htmlhttp://en.wikipedia.org/wiki/GSMhttp://developer.sonyericsson.com/getDocument.do?docId=65054

vtu final report draft for project on smart car parking security system

Documents