143728920 Rfid and Gsm Based Home Security System

HBeonLabs

Off. No. 46, 1st Floor, Kadamba Complex

Gamma-I, Greater Noida (India) - 201308

Contact us:

+91-120-4298000

+91-9212314779

[email protected]

[email protected] www. hbeonlabs.com

RFID AND GSM BASED HOME SECURITY

SYSTEM

Submitted By:

INTRODUCTION

This project RFID+GSM based Home/Office security system is

developed to build a security system for a home/office to

prevent the other persons to enter into the important

room/chamber by controlling radio frequency identification by

checking a suitable RFID card and their record through GSM.

The RFID tag gives the unique id whenever it reads the

card information. This id information is send to the micro

controller to check the correct card to take a security action. If

the card id matches with the original information, it allows

entering into the room and acknowledges the authorized, if not

gives the buzzer as an indication of wrong person tried to enter

into the room and a message regarding this also.

In present system there are no efficient methods for accurate

identifications, there are certain places where accuracy is

important mainly in banking, health care and government

sectors. This application will provide RFID tag based system

which uses microcontroller.

RFID is one the fast growing technology all over the world for

identifying and tracing goods. This system can help hospitals to

find expensive equipment in less time and provide better

services for patients. This technology is also widely used in

pharmaceuticals and logistics. As far as GSM is concerned, we

all know its capability and using this technology with RFID

provides solutions for long distance communication.

A BRIEF INTRODUCTION TO 8051

MICROCONTROLLER:

When we have to learn about a new computer we have to

familiarize about the machine capability we are using, and we

can do it by studying the internal hardware design (devices

architecture), and also to know about the size, number and the

size of the registers.

A microcontroller is a single chip that contains the

processor (the CPU), non-volatile memory for the program

(ROM or flash), volatile memory for input and output (RAM), a

clock and an I/O control unit. Also called a "computer on a

chip," billions of microcontroller units (MCUs) are embedded

each year in a myriad of products from toys to appliances to

automobiles. For example, a single vehicle can use 70 or more

microcontrollers. The following picture describes a general

block diagram of microcontroller.

AT89S52: The AT89S52 is a low-power, high-performance

CMOS 8-bit microcontroller with 8K bytes of in-system

programmable Flash memory. The device is manufactured using

Atmel’s high-density nonvolatile memory technology and is

compatible with the industry-standard 80C51 instruction set and

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

reprogrammed in-system or by a conventional nonvolatile

memory programmer. By combining a versatile 8-bit CPU with

in-system programmable Flash on a monolithic chip, the Atmel

AT89S52 is a powerful microcontroller, which provides a highly

flexible and cost-effective solution to many, embedded control

applications. The AT89S52 provides the following standard

features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines,

Watchdog timer, two data pointers, three 16-bit timer/counters, a

six-vector two-level interrupt architecture, a full duplex serial

port, on-chip oscillator, and clock circuitry. In addition, the

AT89S52 is designed with static logic for operation down to

zero frequency and supports two software selectable power

saving modes. 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

con-tents but freezes the oscillator, disabling all other chip

functions until the next interrupt.

The hardware is driven by a set of program instructions, or

software. Once familiar with hardware and software, the user

can then apply the microcontroller to the problems easily.

The pin diagram of the 8051 shows all of the input/output pins

unique to microcontrollers:

The following are some of the capabilities of 8051

microcontroller.

1. Internal ROM and RAM

2. I/O ports with programmable pins

3. Timers and counters

4. Serial data communication


unique to microcontrollers:


Internal ROM and RAM

I/O ports with programmable pins

Timers and counters

Serial data communication



The 8051 architecture consists of these specific features:

• 16 bit PC &data pointer (DPTR)

• 8 bit program status word (PSW)

• 8 bit stack pointer (SP)

• Internal ROM 4k

• Internal RAM of 128 bytes.

• 4 register banks, each containing 8 registers

• 80 bits of general purpose data memory

• 32 input/output pins arranged as four 8 bit ports: P0-P3

• Two 16 bit timer/counters: T0-T1

• Two external and three internal interrupt sources Oscillator and

clock circuits.

BLOCK DIAGRAM

POWER

SUPPLY

8

9

S

5

2

GSM MODEM

LIQUID CRYSTAL DISPLAY

MOBILE (USER) RFID

READER

MODULE

L293D

DC MOTOR

CIRCUIT DIAGRAM

COMPONENT LIST

Name Capacity Quantity

2 Pin Connector Screw 1

2 Pin Connector Male 1

Diode IN40007 4

Regulator 7805 1

Regulator 7812 1

Capacitor 1000µf 1

Capacitor 10µf 1

Ceramic Capacitor 22pf 2

Crystal 11.0592mhz 1

Push Button 1

40 Pin Base 1

8051 AT89S52 1

LED 2

LCD Base 16 Pin 1

LCD 16*2 1

Resistance 220Ω 2

Resistance 1k 1

Resistance 10k 1

RFID READER 1

GSM MODEM 1

16 Pin Base 1

L293D Motor driving ic

1

DC motor 1

HARDWARE DESCRIPTION:

1. POWER SUPPLY:

Power supply is a reference to a source of electrical power. A

device or system that supplies electrical or other types of energy

to an output load or group of loads is called a power supply

unit or PSU. The term is most commonly applied to electrical

energy supplies, less often to mechanical ones, and rarely to

others. Here in our application we need a 5v DC power supply

for all electronics involved in the project. This requires step

down transformer, rectifier, voltage regulator, and filter circuit

for generation of 5v DC power. Here a brief description of all

the components is given as follows:

TRANSFORMER:

transformer is a device that transfers electrical energy from

one circuit to another through inductively coupled conductors —

the transformer's coils or "windings". Except for air-core

transformers, the conductors are commonly wound around a

single iron-rich core, or around separate but magnetically-

coupled cores. A varying current in the first or "primary"

winding creates a varying magnetic field in the core (or cores) of

the transformer. This varying magnetic field induces a varying

electromotive force (EMF) or "voltage" in the "secondary"

winding. This effect is called mutual induction.

If a load is connected to the secondary circuit, electric charge

will flow in the secondary winding of the transformer and

transfer energy from the primary circuit to the load connected in

the secondary circuit.

The secondary induced voltage VS, of an ideal transformer, is

scaled from the primary VP by a factor equal to the ratio of the

number of turns of wire in their respective windings:

By appropriate selection of the numbers of turns, a transformer

thus allows an alternating voltage to be stepped up — by making

NS more than NP — or stepped down, by making it

BASIC PARTS OF A TRANSFORMER

In its most basic form a transformer consists of:

• A primary coil or winding.

• A secondary coil or winding.

• A core that supports the coils or windings.

Refer to the transformer circuit in figure as you read the

following explanation: The primary winding is connected to a

60-hertz ac voltage source. The magnetic field (flux) builds up

(expands) and collapses (contracts) about the primary winding.

The expanding and contracting magnetic field around the

primary winding cuts the secondary winding and induces an

alternating voltage into the winding. This voltage causes

alternating current to flow through the load. The voltage may be

stepped up or down depending on the design of the primary and

secondary windings.

THE COMPONENTS OF A TRANSFORMER

Two coils of wire (called windings) are wound on some type of

core material. In some cases the coils of wire are wound on a

cylindrical or rectangular cardboard form. In effect, the core

material is air and the transformer is called an AIR-CORE

TRANSFORMER. Transformers used at low frequencies, such

as 60 hertz and 400 hertz, require a core of low-reluctance

magnetic material, usually iron. This type of transformer is

called an IRON-CORE TRANSFORMER. Most power

transformers are of the iron-core type. The principle parts of a

transformer and their functions are:

• The CORE, which provides a path for the magnetic lines of flux.

• The PRIMARY WINDING, which receives energy from the ac

source.

• The SECONDARY WINDING, which receives energy from the

primary winding and delivers it to the load.

• The ENCLOSURE, which protects the above components from

dirt, moisture, and mechanical damage.

BRIDGE RECTIFIER

A bridge rectifier makes use of four diodes in a bridge

arrangement to achieve full-wave rectification. This is a widely

used configuration, both with individual diodes wired as shown

and with single component bridges where the diode bridge is

wired internally.

Basic operation

According to the conventional model of current flow originally

established by Benjamin Franklin and still followed by most

engineers today, current is assumed to flow through electrical

conductors from the positive to the negative pole. In actuality,

free electrons in a conductor nearly always flow from the

negative to the positive pole. In the vast majority of

applications, however, the

irrelevant. Therefore, in the discussion below the conventional

model is retained.

In the diagrams below, when the input connected to the

corner of the diamond is

right corner is negative

terminal to the right along the

and returns to the lower

path.

When the input connected to the

input connected to the

from the lower supply terminal to the right along the

the output, and returns to the

path.

applications, however, the actual direction of current flow is


In the diagrams below, when the input connected to the

corner of the diamond is positive, and the input connected to the

negative, current flows from the

terminal to the right along the red (positive) path to the output,

lower supply terminal via the blue

When the input connected to the left corner is negative

input connected to the right corner is positive, current flows

supply terminal to the right along the

the output, and returns to the upper supply terminal via the

direction of current flow is


In the diagrams below, when the input connected to the left

, and the input connected to the

, current flows from the upper supply

(positive) path to the output,

blue (negative)

negative, and the

, current flows

supply terminal to the right along the red path to

supply terminal via the blue

In each case, the upper right output remains positive and lower

right output negative. Since this is true whether the input is AC

or DC, this circuit not only produces a DC

input, it can also provide what is sometimes called "reverse

polarity protection". That is, it permits normal functioning of

DC-powered equipment when batteries have been installed

backwards, or when the leads (wires) from a DC power sour

have been reversed, and protects the equipment from potential

damage caused by reverse polarity.

Prior to availability of integrated electronics, such a bridge

rectifier was always constructed from discrete components.

Since about 1950, a single four

the four diodes connected in the bridge configuration became a



or DC, this circuit not only produces a DC output from an AC



powered equipment when batteries have been installed

backwards, or when the leads (wires) from a DC power sour


damage caused by reverse polarity.



Since about 1950, a single four-terminal component containing




output from an AC



powered equipment when batteries have been installed

backwards, or when the leads (wires) from a DC power source




rminal component containing


standard commercial component and is now available with

various voltage and current ratings.

OUTPUT SMOOTHING

For many applications, especially with single phase AC

the full-wave bridge serves to convert an AC input into a DC

output, the addition of a capacitor may be desired because the

bridge alone supplies an output of fixed polarity but

continuously varying or "pulsating" magnitude (see diagram

above).

The function of this capacitor, known as a reservoir capacitor (or

smoothing capacitor) is to lessen the variation in (or 'smooth')

the rectified AC output voltage waveform from the bridge. One

explanation of 'smoothing' is that the capacitor provides a lo

impedance path to the AC component of the output, reducing the


various voltage and current ratings.

For many applications, especially with single phase AC

wave bridge serves to convert an AC input into a DC







explanation of 'smoothing' is that the capacitor provides a lo



For many applications, especially with single phase AC where

wave bridge serves to convert an AC input into a DC







explanation of 'smoothing' is that the capacitor provides a low


AC voltage across, and AC current through, the resistive load. In

less technical terms, any drop in the output voltage and current

of the bridge tends to be canceled by loss of charge in the

capacitor. This charge flows out as additional current through

the load. Thus the change of load current and voltage is reduced

relative to what would occur without the capacitor. Increases of

voltage correspondingly store excess charge in the capacitor,

thus moderating the change in output voltage / current.

The simplified circuit shown has a well-deserved reputation for

being dangerous, because, in some applications, the capacitor

can retain a lethal charge after the AC power source is removed.

If supplying a dangerous voltage, a practical circuit should

include a reliable way to safely discharge the capacitor. If the

normal load cannot be guaranteed to perform this function,

perhaps because it can be disconnected, the circuit should

include a bleeder resistor connected as close as practical across

the capacitor. This resistor should consume a current large

enough to discharge the capacitor in a reasonable time, but small

enough to minimize unnecessary power waste.

Because a bleeder sets a minimum current drain, the regulation

of the circuit, defined as percentage voltage change from

minimum to maximum load, is improved. However in many

cases the improvement is of insignificant magnitude.

The capacitor and the load resistance have a typical time

constant τ = RC where C and R are the capacitance and load

resistance respectively. As long as the load resistor is large

enough so that this time constant is much longer than the time of

one ripple cycle, the above configuration will produce a

smoothed DC voltage across the load.

In some designs, a series resistor at the load side of the capacitor

is added. The smoothing can then be improved by adding

additional stages of capacitor–resistor pairs, often done only for

sub-supplies to critical high-gain circuits that tend to be

sensitive to supply voltage noise.

The idealized waveforms shown above are seen for both voltage

and current when the load on the bridge is resistive. When the

load includes a smoothing capacitor, both the voltage and the

current waveforms will be greatly changed. While the voltage is

smoothed, as described above, current will flow through the

bridge only during the time when the input voltage is greater

than the capacitor voltage. For example, if the load draws an

average current of n Amps, and the diodes conduct for 10% of

the time, the average diode current during conduction must be

10n Amps. This non-sinusoidal current leads to harmonic

distortion and a poor power factor in the AC supply.

In a practical circuit, when a capacitor is directly connected to

the output of a bridge, the bridge diodes must be sized to

withstand the current surge that occurs when the power is turned

on at the peak of the AC voltage and the capacitor is fully

discharged. Sometimes a small series resistor is included before

the capacitor to limit this current, though in most applications

the power supply transformer's resistance is already sufficient.

Output can also be smoothed using a choke and second

capacitor. The choke tends to keep the current (rather than the

voltage) more constant. Due to the relatively high cost of an

effective choke compared to a resistor and capacitor this is not

employed in modern equipment.

Some early console radios created the speaker's constant field

with the current from the high voltage ("B +") power supply,

which was then routed to the consuming circuits, (permanent

magnets were then too weak for good performance) to create the

speaker's constant magnetic field. The speaker field coil thus

performed 2 jobs in one: it acted as a choke, filtering the power

supply, and it produced the magnetic field to operate the

speaker.

REGULATOR IC (78XX)

It is a three pin IC used as a voltage regulator. It converts

unregulated DC current into regulated DC current.

Normally we get fixed output by connecting the voltage

regulator at the output of the filtered DC (see in above diagram).

It can also be used in circuits to get a low DC voltage from a

high DC voltage (for example we use 7805 to get 5V from 12V).

There are two types of voltage regulators 1. fixed voltage

regulators (78xx, 79xx) 2. variable voltage regulators(LM317)

In fixed voltage regulators there is another classification 1. +ve

voltage regulators 2. -ve voltage regulators POSITIVE

VOLTAGE REGULATORS This include 78xx voltage

regulators. The most commonly used ones are 7805 and 7812.

7805 gives fixed 5V DC voltage if input voltage is in (7.5V,

20V).

The Capacitor Filter

The simple capacitor filter is the most basic type of power

supply filter. The application of the simple capacitor filter is

very limited. It is sometimes used on extremely high-voltage,

low-current power supplies for cathode-ray and similar electron

tubes, which require very little load current from the supply. The

capacitor filter is also used where the power-supply ripple

frequency is not critical; this frequency can be relatively high.

The capacitor (C1) shown in figure 4-15 is a simple filter

connected across the output of the rectifier in parallel with the

load.

Full-wave rectifier with a capacitor filter.

When this filter is used, the RC charge time of the filter

capacitor (C1) must be short and the RC discharge time must be

long to eliminate ripple action. In other words, the capacitor

must charge up fast, preferably with no discharge at all. Better

filtering also results when the input frequency is high; therefore,

the full-wave rectifier output is easier to filter than that of the

half-wave rectifier because of its higher frequency.

For you to have a better understanding of the effect that filtering

has on Eavg, a comparison of a rectifier circuit with a filter and

one without a filter is illustrated in views A and B of figure 4-

16. The output waveforms in figure 4-16 represent the unfiltered

and filtered outputs of the half-wave rectifier circuit. Current

pulses flow through the load resistance (RL) each time a diode

conducts. The dashed line indicates the average value of output

voltage. For the half-wave rectifier, Eavg is less than half (or

approximately 0.318) of the peak output voltage. This value is

still much less than that of the applied voltage. With no

capacitor connected across the output of the rectifier circuit, the

waveform in view A has a large pulsating component (ripple)

compared with the average or dc component. When a capacitor

is connected across the output (view B), the average value of

output voltage (Eavg) is increased due to the filtering action of

capacitor C1.

UNFILTERED

Half-wave rectifier with and without filtering.

FILTERED

The value of the capacitor is fairly large (several microfarads),

thus it presents a relatively low reactance to the pulsating current

and it stores a substantial charge.

The rate of charge for the capacitor is limited only by the

resistance of the conducting diode, which is relatively low.

Therefore, the RC charge time of the circuit is relatively short.

As a result, when the pulsating voltage is first applied to the

circuit, the capacitor charges rapidly and almost reaches the

peak value of the rectified voltage within the first few cycles.

The capacitor attempts to charge to the peak value of the

rectified voltage anytime a diode is conducting, and tends to

retain its charge when the rectifier output falls to zero. (The

capacitor cannot discharge immediately.) The capacitor slowly

discharges through the load resistance (RL) during the time the

rectifier is non-conducting.

The rate of discharge of the capacitor is determined by the value

of capacitance and the value of the load resistance. If the

capacitance and load-resistance values are large, the RC

discharge time for the circuit is relatively long.

A comparison of the waveforms shown in figure 4-16 (view A

and view B) illustrates that the addition of C1 to the circuit

results in an increase in the average of the output voltage (Eavg)

and a reduction in the amplitude of the ripple component (Er)

which is normally present across the load resistance.

Now, let's consider a complete cycle of operation using a half-

wave rectifier, a capacitive filter (C1), and a load resistor (RL).

As shown in view A of figure 4-17, the capacitive filter (C1) is

assumed to be large enough to ensure a small reactance to the

pulsating rectified current. The resistance of RL is assumed to be

much greater than the reactance of C1 at the input frequency.

When the circuit is energized, the diode conducts on the positive

half cycle and current flows through the circuit, allowing C1 to

charge. C1 will charge to approximately the peak value of the

input voltage. (The charge is less than the peak value because of

the voltage drop across the diode (D1)). In view A of the figure,

the charge on C1 is indicated by the heavy solid line on the

waveform. As illustrated in view B, the diode cannot conduct on

the negative half cycle because the anode of D1 is negative with

respect to the cathode. During this interval, C1 discharges

through the load resistor (RL). The discharge of C1 produces the

downward slope as indicated by the solid line on the waveform

in view B. In contrast to the abrupt fall of the applied ac voltage

from peak value to zero, the voltage across C1 (and thus across

RL) during the discharge period gradually decreases until the

time of the next half cycle of rectifier operation. Keep in mind

that for good filtering, the filter capacitor should charge up as

fast as possible and discharge as little as possible.

Figure 4-17A. - Capacitor filter circuit (positive and negative

half cycles). POSITIVE HALF-CYCLE

Figure 4-17B. - Capacitor filter circuit (positive and negative

half cycles). NEGATIVE HALF-CYCLE

Since practical values of C1 and RL ensure a more or less

gradual decrease of the discharge voltage, a substantial charge

remains on the capacitor at the time of the next half cycle of

operation. As a result, no current can flow through the diode

until the rising ac input voltage at the anode of the diode exceeds

the voltage on the charge remaining on C1. The charge on C1 is

the cathode potential of the diode. When the potential on the

anode exceeds the potential on the cathode (the charge on C1),

the diode again conducts, and C1 begins to charge to

approximately the peak value of the applied voltage.

After the capacitor has charged to its peak value, the diode will

cut off and the capacitor will start to discharge. Since the fall of

the ac input voltage on the anode is considerably more rapid

than the decrease on the capacitor voltage, the cathode quickly

become more positive than the anode, and the diode ceases to

conduct.

Operation of the simple capacitor filter using a full-wave

rectifier is basically the same as that discussed for the half-wave

rectifier. Referring to figure 4-18, you should notice that

because one of the diodes is always conducting on. either

alternation, the filter capacitor charges and discharges during

each half cycle. (Note that each diode conducts only for that

portion of time when the peak secondary voltage is greater than

the charge across the capacitor.)

Figure 4-18. - Full-wave rectifier (with capacitor filter).

Another thing to keep in mind is that the ripple component (E r)

of the output voltage is an ac voltage and the average output

voltage (Eavg) is the dc component of the output. Since the filter

capacitor offers a relatively low impedance to ac, the majority of

the ac component flows through the filter capacitor. The ac

component is therefore bypassed (shunted) around the load

resistance, and the entire dc component (or Eavg) flows through

the load resistance. This statement can be clarified by using the

formula for XC in a half-wave and full-wave rectifier. First, you

must establish some values for the circuit.

As you can see from the calculations, by doubling the frequency

of the rectifier, you reduce the impedance of the capacitor by

one-half. This allows the ac component to pass through the



half. This allows the ac component to pass through the



half. This allows the ac component to pass through the

capacitor more easily. As a result, a full

much easier to filter than that of a half

Remember, the smaller the X

to the load resistance, the better the filtering action. Since

the largest possible capacitor will provide the best filtering.

Remember, also, that the load resistance is an important

consideration. If load resistance is made small, the load current

increases, and the average value of output voltage (E

decreases. The RC discharge time constant is a direct function of

the value of the load resistance; therefore, the rate of capacitor

voltage discharge is a direct function of the current through the

load. The greater the load current, the more rapid the discharge

of the capacitor, and the lower the average value of output

voltage. For this reason, the simple capacitive filter is seldom

used with rectifier circuits that must supply a relatively large

load current. Using the simple capacitive filter in conjunction

with a full-wave or bridge rectifier provides improved filtering

more easily. As a result, a full-wave rectifier output is

much easier to filter than that of a half-wave rectifier.

Remember, the smaller the XC of the filter capacitor with respect


gest possible capacitor will provide the best filtering.



increases, and the average value of output voltage (E

discharge time constant is a direct function of




pacitor, and the lower the average value of output




wave or bridge rectifier provides improved filtering

wave rectifier output is

wave rectifier.

of the filter capacitor with respect


gest possible capacitor will provide the best filtering.



increases, and the average value of output voltage (Eavg)

discharge time constant is a direct function of




pacitor, and the lower the average value of output




wave or bridge rectifier provides improved filtering

because the increased ripple frequency decreases the capacitive

reactance of the filter capacitor.

CIRCUIT DIAGRAM OF POWER SUPPLY

DIODE

The diode is a p-n junction device. Diode is the component

used to control the flow of the current in any one direction. The

diode widely works in forward bias.

Diode When the current flows from the P to N direction. Then it

is in forward bias. The Zener diode is used in reverse bias

function i.e. N to P direction. Visually the identification of the

diode`s terminal can be done by identifying he silver/black line.

The silver/black line is the negative terminal (cathode) and the

other terminal is the positive terminal (cathode).

APPLICATION

•Diodes: Rectification, free-wheeling, etc

•Zener diode: Voltage control, regulator etc.

•Tunnel diode: Control the current flow, snobbier circuit, etc

RESISTORS

The flow of charge through any material encounters an

opposing force similar in many respects to mechanical friction

.this opposing force is called resistance of the material .in some

electric circuit resistance is deliberately introduced in form of

resistor. Resistor used fall in three categories , only two of

which are color coded which are metal film and carbon film

resistor .the third category is the wire wound type ,where value

are generally printed on the vitreous paint finish of the

component. Resistors are in ohms and are represented in Greek

letter omega, looks as an upturned horseshoe. Most electronic

circuit require resistors to make them work properly and it is

obliviously important to find out something about the different

types of resistors available. Resistance is measured in ohms, the

symbol for ohm is an omega ohm. 1 ohm is quite small for

electronics so resistances are often given in kohm and Mohm.

Resistors used in electronics can have resistances as low as 0.1

ohm or as high as 10 Mohm.

FUNCTION

Resistor restrict the flow of electric current, for example a

resistor is placed in series with a light-emitting diode(LED) to

limit the current passing through the LED.

TYPES OF RESISTORS

FIXED VALUE RESISTORS

It includes two types of resistors as carbon film and metal film

.These two types are explained under

CARBON FILM RESISTORS

During manufacture, at in film of carbon is deposited onto a

small ceramic rod. The resistive coating is spiraled away in an

automatic machine until the resistance between there two ends

of the rods is as close as possible to the correct value. Metal

leads and end caps are added, the resistors is covered with an

insulating coating and finally painted with colored bands to

indicate the resistor value

Carbon Film Resistors

Another example for a Carbon 22000 Ohms or 22 Kilo-Ohms

also known as 22K at 5% tolerance: Band 1 = Red, 1st digit

Band 2 = Red, 2nd digit Band 3 = Orange, 3rd digit, multiply

with zeros, in this case 3 zero's Band 4 = Gold, Tolerance, 5%

METAL FILM RESISTORS

Metal film and metal oxides resistors are made in a similar way,

but can be made more accurately to within ±2% or ±1% of their

nominal vale there are some difference in performance between

these resistor types, but none which affects their use in simple

circuit.

WIRE WOUND RESISTOR

A wire wound resistor is made of metal resistance wire, and

because of this, they can be manufactured to precise values.

Also, high wattage resistors can be made by using a thick wire

material. Wire wound resistors cannot be used for high

frequency circuits. Coils are used in high frequency circuit. Wire

wound resistors in a ceramic case, strengthened with special

cement. They have very high power rating, from 1 or 2 watts to

dozens of watts. These resistors can become extremely hot when

used for high power application, and this must be taken into

account when designing the circuit.

TESTING

Resistors are checked with an ohm meter/millimeter. For a

defective resistor the ohm-meter shows infinite high reading.

CAPACITORS

In a way, a capacitor is a little like a battery. Although they

work in completely different ways, capacitors and batteries both

store electrical energy. If you have read How Batteries Work ,

then you know that a battery has two terminals. Inside the

battery, chemical reactions produce electrons on one terminal

and absorb electrons at the other terminal.

BASIC

Like a battery, a capacitor has two terminals. Inside the

capacitor, the terminals connect to two metal plates separated by

a dielectric. The dielectric can be air, paper, plastic or anything

else that does not conduct electricity and keeps the plates from

touching each other. You can easily make a capacitor from two

pieces of aluminum foil and a piece of paper. It won't be a

particularly good capacitor in terms of its storage capacity, but it

will work.

In an electronic circuit, a capacitor is shown like this:

When you connect a capacitor to a battery, here’s what happens:

•The plate on the capacitor that attaches to the negative terminal

of the battery accepts electrons that the battery is producing.

•The plate on the capacitor that attaches to the positive terminal

of the battery loses electrons to the battery.

TESTING

To test the capacitors, either analog meters or specia

l digital meters with the specified function are used. The non-

electrolyte capacitor can be tested by using the digital meter.

Multi – meter mode : Continuity Positive probe : One end

Negative probe : Second end Display : `0`(beep sound

occur) `OL` Result : Faulty OK

LED

LED falls within the family of P-N junction devices. The light

emitting diode (LED) is a diode that will give off visible light

when it is energized. In any forward biased P-N junction there

is, with in the structure and primarily close to the junction, a

recombination of hole and electrons. This recombination

requires that the energy possessed by the unbound free electron

be transferred to another state. The process of giving off light by

applying an electrical source is called electroluminescence.

LED is a component used for indication. All the functions being

carried out are displayed by led .The LED is diode which glows

when the current is being flown through it in forward bias

condition. The LEDs are available in the round shell and also in

the flat shells. The positive leg is longer than negative leg.

RADIO FREQUENCY IDENTIFICATION (RFID)

INTRODUCTION

RFID is the use of an object (typically referred to as an RFID

tag) applied to or incorporated into a product, animal, or person

for the purpose of identification and tracking using radio waves.

Some tags can be read from several meters away and beyond the

line of sight of the reader.

RFIDs are easy to conceal or incorporate in other items. For

example, in 2009 researchers at Bristol University successfully

glued RFID micro transponders to live ants in order to study

their behavior. This trend towards increasingly miniaturized

RFIDs is likely to continue as technology advances. However,

the ability to read at distance is limited by the inverse-square

law.

RFID is becoming increasingly prevalent as the price of the

technology decreases. Governments use RFID applications for

traffic management, while automotive companies use various

RFID tracking solutions for product management. Many of these

solutions may work together in the future, though privacy

regulations prevent many initiatives from moving forward at the

same pace that technology allows.

COMPONENTS OF RFID SYSTEM

An RFID system consists of RFID tags, a means of reading or

interrogating the tags and a means of communicating the data to

a host computer or information management system. The system

will also include a facility for entering or programming data into

tags, if it is not done at the source by the manufacturer. There

may also be present antennas for communication between the

tag and the reader.

A typical RFID system is made up of three components:

1. Tags,

2. Readers

3. Host computer system.

RFID TAGS

An RFID tag is a tiny radio device that is also referred to as a

transponder, smart tag, smart label or radio barcode. The word

transponder is derived from the words transmitter and responder.

The tag responds to a transmitted or communicated request for

the data it carries. The tag comprises a simple silicon microchip

(typically less than half a millimeter in size) attached to a small

flat aerial and mounted on a substrate.

The transponder memory may comprise of read-only (ROM),

random access (RAM), and non-volatile programmable memory

for data storage depending on the type and sophistication of the

device. The ROM-based memory is used to accommodate

security data and the transponder operating system instructions.

The RAM-based memory is used for temporary data storage

during transponder interrogation and response. The non-volatile

programmable memory (EEPROM) used to store the

transponder data and needs to be non-volatile to ensure that the

data is retained when the device is in its quiescent or power-

saving ‘sleep’ state.

Data buffers are further components of memory used to

temporarily hold the incoming data following demodulation and

outgoing data for modulation and interface with the transponder

antenna. The interface circuitry provides the fa

and accommodate the interrogation field energy for powering

purposes in passive transponders and triggering of the

transponder response. The transponder antenna senses the

interrogating field and serves as the means for transmitting the

transponder response for interrogation.

TYPES OF RFID

On the basis of the presence of battery, tags can be

classified into

Active tags

Passive tags.

RFID Tag Data Format




antenna. The interface circuitry provides the fa





ansponder response for interrogation.

TAGS


RFID Tag Data Format




antenna. The interface circuitry provides the facility to direct






Printed barcode labels generally conform to the Universal

Product Code standard (UPC) of product identification. RFID

tags used to identify products in the supply chain serve the same

purpose, so it’s often expeditious to explain RFID tags simply as

ʺelectronic barcodes.ʺ Both RFID tags and barcode labels

digitally convey information about objects. Currently, ʺClass

1+ʺ RFID tags are available with a digital memory of 96 bits,

each bit being either logic 1 or a logic 0. Because alphanumeric

characters (i.e., A‐to‐Z and 0‐9) each require 8 bits of memory,

it’s possible to store 12 characters in an RFID tag (which isn’t

saying much). On the other hand those 96 bits represent a

possible 79,228,162,514,264,300,000,000,000,000 (that’s over

79.2 trillion) unique numerical identities. Or you could split the

96 bits into fields that each represents some characteristic of the

object, creating a sort of family tree of objects.

There are two basic tag data architectures. One is to include

all information about a product (e.g., its size, date of

manufactures, the quality inspector’s name) on the tag itself.

This has the advantage of decentralizing the data, but has a

drawback in that the increased memory requirements on the tag

increase its complexity and cost. The other way is for the tag to

serve as a “license plate” for the object, which can be associated

with a database of its characteristics located in a centralized

database.

In 2000, Sarma, Brock, and Ashton of MITʹs Auto‐ID

Project foresaw a world where “all physical objects…act as

nodes in a networked physical world.” 1

They propose an open

architecture system that is independent of the specific tag

technology affixed or built into the object being tracked. They

proposed a common identification standard or Electronic

Product Code (ePC) standard.

HEADER MANUFACTURER

CODE

PRODUCT

CODE

SERIAL

NUMBER

The header serves as a way of identifying the format of the

sequence of bits that follow in the EPC. This makes system

coding more flexible. That is a critical innovation because it

allows for the use of various independent standards of

identification to be understood by users of other formats.

FREQUENCY RANGE OF RFID

There are several versions of RFID that operate at different radio

frequencies. The choice of frequency is dependent on the

business requirements and read environment – it is not a

technology where ‘one size fits all’ applications.

Three primary frequency bands are being used for RFID:

• Low Frequency (125/134KHz) – Most commonly used for

access control, animal tracking and asset tracking.

• High -Frequency (13.56 MHz) – Used where medium data

rate and read ranges up to about 1.5 meters are acceptable.

This frequency also has the advantage of not being

susceptible to interference from the presence of water or

metals.

• Ultra High-Frequency (850 MHz to 950 MHz) – offer the

longest read ranges of up to approximately 3 meters and

high reading speeds.

READERS

The reader, sometimes called an interrogator or

scanner, sends and receives RF data to and from the tag via

antennae. A reader may have multiple antennae that are

responsible for sending and receiving radio waves.

The readers can be fixed or mobile, can read information

stored on the tags and write information to them. This can be

achieved without direct line of sight and in environments where

traditional data collection could not operate. A major advantage

is that information can be written to the tag multiple times so

storing a history that travels with the article.

The reader/interrogators can differ considerably in

complexity depending on the type of tags being supported and

functions to be fulfilled. The overall function is to provide the

means of communicating with the tag and facilitating data

transfer. Functions performed by readers include signal

conditioning, parity error checking and correction.

Once the signal from a transponder has been correctly

received and decoded, algorithms can be applied to decide

whether the signal is a repeat transmission and may then instruct

the transponder to stop transmitting. This is known as Command

Response Protocol and is used to circumvent the problem of

reading multiple tags in a short span of time.

Using interrogators in this way is also referred to as Hands

Down Polling. A more secure, but slower tag polling technique

is called Hands Up Polling which involves the interrogator

looking for tags with specific identities and interrogating them,

in turn. A further approach uses multiple readers, multiplexed

into one interrogator but results in cost increase.

PRINCIPLE OF WORKING

In the RFID system, the reader sends out a radio

frequency wave to the tag and the tag broadcasts back its stored

data to the reader. The system has two antennas, one for the tag

and the other on the reader. The data collected from the tag can

either be sent directly to a host computer through standard

interfaces or it can be stored in a portable reader and later

updated to the computer for data processing. The automatic

reading and direct use of tag data is called ‘automatic data

capture’.

When the tag which is battery free, is to be read, the reader

sends out a power pulse to the antenna lasting for about

50ms.The magnetic field generated is collected by the antenna in

the transponder that is tuned to the same frequency. This

received energy is rectified and stored on a capacitor within the

transponder.

When the power pulse has finished, the transponder

immediately transmits back its data, using the energy stored

within its capacitor as its power source. The data is picked up by

the receiving antenna and decoded by the reader unit.

Once all the data has been transmitted, the storage capacitor

is discharged resetting the transponder to make it ready for the

next read cycle. The period between transmission pulses is

called sync time and lasts between 20ms and 50ms depending on

the system set up.

TAG

Fig. 8.3.1 WORKING OF RFID SYSTEM

The scanning antennas can be permanently affixed to a surface;

handheld antennas are also available. They can take whatever

shape you need; for example, you could build them into a door

frame to accept data from persons or objects passing through.

When an RFID tag passes through the field of the scanning

antenna, it detects the activation signal from the antenna. That

"wakes up" the RFID chip, and it transmits the information on

its microchip to be picked up by the scanning antenna.

ADVANTAGES

RFID technology permits no line of sight reading.

Robustness and reliability under difficult environmental

conditions.

These tags can be read through water, snow, concrete,

bricks, plastics, wood, and most non-metallic materials

Available in a wide variety of physical forms, shapes, sizes

and protective housings.

RFID tags can be read at very high speeds.

The tag need not be on the surface of the object (and is

therefore not subject to wear).

The read time is typically less than 100 milliseconds

Large numbers of tags can be read at once rather than item

by item.

APPLICATIONS

Principle areas of applications of RFID include:

1. Transportation

2. Manufacturing and processing.

3. Security.

Texas Instruments Radio Frequency Identification (TI-

RFid) Systems has introduced its new RFID tag for textile rental

and dry cleaning applications. TI-RFid tags provide more

accurate identification and greater accountability as well as

improved handling through each stage of cleaning and

processing to final customer delivery.

RFID system allows booksellers to gain such information as the

range of books a shopper has browsed, the number of times a

particular title was picked up, and even the length of time spent

flipping through pages. The shelves can scan the contents of the

shelves and, via computer, alert store employees when supplies

are running low or when theft is detected.[4]

RFID tags loaded with biometric information will be embedded

in passports to ensure travelers comply with security regulations.

RFID technology is also being used to improve luggage

handling in airports.

Certain specific applications of RFID include:

1. Fleet management.

2. Inventory and asset Management

GLOBAL SYSTEM FOR MOBILE COMMUNICATION (GSM)

INTRODUCTION

Definition

GSM, which stands for Global System for Mobile

communications, reigns (important) as the world’s most widely

used cell phone technology. Cell phones use a cell phone service

carrier’s GSM network by searching for cell phone towers in the

nearby area. 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.

GSM – ARCHITECTURE

A GSM network consists of several functional entities

whose functions and interfaces are defined. The GSM network

can be divided into following broad parts.

The Mobile Station (MS)

The Base Station Subsystem (BSS)

The Network Switching Subsystem (NSS)

The Operation Support Subsystem (OSS)

Following fig shows the simple architecture diagram of GSM

Network.

The added components of the GSM architecture include the

functions of the databases and messaging systems:

Home Location Register (HLR)

Visitor Location Register (VLR)

Equipment Identity Register (EIR)

Authentication Center (AuC)

SMS Serving Center (SMS SC)

Gateway MSC (GMSC)

Chargeback Center (CBC)

Transcoder and Adaptation Unit (TRAU)

Following fig shows the diagram of GSM Network along with

added elements.

Fig:9.2.1

The MS and the BSS communicate across the Um

interface, also known as the air interface or radio link. The BSS

communicates with the Network Service Switching center

across the A interface.

GSM network areas

In a GSM network, the following areas are defined:

Cell: Cell is the basic service area, one BTS covers one cell.

Each cell is given a Cell Global Identity (CGI), a number that

uniquely identifies the cell.

Location Area: A group of cells form a Loca

the area that is paged when a subscriber gets an incoming call.

Fig:9.2.1 GSM Network along with added elements.




across the A interface.

areas


Cell is the basic service area, one BTS covers one cell.


uniquely identifies the cell.

A group of cells form a Location Area. This is


GSM Network along with added elements.





Cell is the basic service area, one BTS covers one cell.


tion Area. This is


Each Location Area is assigned a Location Area Identity (LAI).

Each Location Area is served by one or more BSCs.

MSC/VLR Service Area: The area covered by one MSC is

called the MSC/VLR service area.

PLMN: The area covered by one network operator is called

PLMN. A PLMN can contain one or more MSCs.

The GSM networks parts are explained as follows

1) Mobile Station

The mobile station (MS) consists of the physical

equipment, such as the radio transceiver, display and digital

signal processors, and a smart card called the Subscriber Identity

Module (SIM). The SIM provides personal mobility, so that

the user can have access to all subscribed services irrespective of

both the location of the terminal and the use of a specific

terminal. By inserting the SIM card into another GSM cellular

phone, the user is able to receive calls at that phone, make calls

from that phone, or receive other subscribed services.

The mobile equipment is uniquely identified by the

International Mobile Equipment Identity (IMEI). The SIM card

contains the International Mobile Subscriber Identity (IMSI),

identifying the subscriber, a secret key for authentication, and

other user information. The IMEI and the IMSI are

independent, thereby providing personal mobility. The SIM

card may be protected against unauthorized use by a password

or personal identity number.

2) 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 specified A-

bis 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. 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 and the Mobile

service Switching Center (MSC). The BSC also translates the

13 kbps voice channel used over the radio link to the standard 64

kbps channel used by the Public Switched Telephone Network

or ISDN.

3) 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 in addition

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, which together form the Network

Subsystem. The MSC provides the connection to the public

fixed network (PSTN or ISDN), and signaling between

functional entities uses the ITUT Signaling System Number 7

(SS7), used 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 (possibly international) 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 current

location of the mobile is in the form of a Mobile Station

Roaming Number (MSRN) which is a regular ISDN number

used to route a call to the MSC where the mobile is currently

located. There is logically one HLR per GSM network,

although it may be implemented as a distributed database.

The Visitor Location Register 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, most manufacturers of switching equipment

implement one VLR together with one MSC, so that the

geographical area controlled by the MSC corresponds to that

controlled by the VLR, simplifying the signaling required.

Note that the MSC contains no information about particular

mobile stations - this information is stored in the location

registers.

The other two registers are used for authentication

and security purposes. The Equipment Identity Register (EIR)

is a database that contains a list of all valid mobile equipment on

the network, where each mobile station is identified by its

International Mobile Equipment Identity (IMEI). An IMEI is

marked as invalid if it has been reported stolen or is not type

approved. The Authentication Center is a protected database

that stores a copy of the secret key stored in each subscriber's

SIM card, which is used for authentication and ciphering of the

radio channel.

GSM - The Base Station Subsystem (BSS)

The BSS is composed of two parts:

The Base Transceiver Station (BTS)

The Base Station Controller (BSC)

The BTS and the BSC communicate across the

specified Abis interface, enabling operations between

components that are made by different suppliers. The radio

components of a BSS may consist of four to seven or nine cells.

A BSS may have one or more base stations. The BSS uses the

Abis interface between the BTS and the BSC. A separate high-

speed line (T1 or E1) is then connected from the BSS to the

Mobile MSC.

The Base Transceiver Station (BTS)

The BTS houses the radio transceivers that define a cell

and handles the radio link protocols with the MS. In a large

urban area, a large number of BTSs may be deployed.

Transcoding and rate adaptation

Time and frequency synchronizing

Voice through full- or half-rate services

Decoding, decrypting, and equalizing received signals

Random access detection

Timing advances

Uplink channel measurements

The Base Station Controller (BSC)

The BSC manages the radio resources for one or

more BTSs. It handles radio channel setup, frequency hopping,

and handovers. The BSC is the connection between the mobile

and the MSC. The BSC also translates the 13 Kbps voice

channel used over the radio link to the standard 64 Kbps channel

used by the Public Switched Telephone Network (PSDN) or

ISDN.

It assigns and releases frequencies and time slots for the MS.

The BSC also handles intercell handover. It controls the power

transmission of the BSS and MS in its area. The function of the

BSC is to allocate the necessary time slots between the BTS and

the MSC. It is a switching device that handles the radio

resources. Additional functions include:

Control of frequency hopping

Performing traffic concentration to reduce the number of

lines from the MSC

Providing an interface to the Operations and Maintenance

Center for the BSS

Reallocation of frequencies among BTSs

Time and frequency synchronization

Power management

Time-delay measurements of received signals from the MS

The Network Switching Subsystem (NSS)

The Network switching system (NSS), the main part of

which is the Mobile Switching Center (MSC), performs the

switching of calls between the mobile and other fixed or mobile

network users, as well as the management of mobile services

such as authentication.

The switching system includes the following functional elements.

Home Location Register (HLR)

The HLR is a database used for storage and

management of subscriptions. The HLR is considered the most

important database, as it stores permanent data about

subscribers, including a subscriber's service profile, location

information, and activity status. When an individual buys a

subscription in the form of SIM then all the information about

this subscription is registered in the HLR of that operator.

Mobile Services Switching Center (MSC)

The central component of the Network Subsystem is

the MSC. The MSC performs the switching of calls between the

mobile and other fixed or mobile network users, as well as the

management of mobile services such as such as registration,

authentication, location updating, handovers, and call routing to

a roaming subscriber. It also performs such functions as toll

ticketing, network interfacing, common channel signaling, and

others. Every MSC is identified by a unique ID.

Visitor Location Register (VLR)

The VLR is a database that contains temporary

information about subscribers that is needed by the MSC in

order to service visiting subscribers. The VLR is always

integrated with the MSC. When a mobile station roams into a

new MSC area, the VLR connected to that MSC will request

data about the mobile station from the HLR. Later, if the mobile

station makes a call, the VLR will have the information needed

for call setup without having to interrogate the HLR each time.

Authentication Center (AUC)

The Authentication Center is a protected database that

stores a copy of the secret key stored in each subscriber's SIM

card, which is used for authentication and ciphering of the radio

channel. The AUC protects network operators from different

types of fraud found in today's cellular world.

Equipment Identity Register (EIR)

The Equipment Identity Register (EIR) is a database

that contains a list of all valid mobile equipment on the network,

where its International Mobile Equipment Identity (IMEI)

identifies each MS. An IMEI is marked as invalid if it has been

reported stolen or is not type approved.

THE OPERATION SUPPORT SUBSYSTEM (OSS)

The operations and maintenance center (OMC) is

connected to all equipment in the switching system and to the

BSC. The implementation of OMC is called the operation and

support system (OSS).

Here are some of the OMC functions:

Administration and commercial operation (subscription,

end terminals, charging and statistics).

Security Management.

Network configuration, Operation and Performance

Management.

Maintenance Tasks.

The operation and Maintenance functions are based on the

concepts of the Telecommunication Management Network

(TMN) which is standardized in the ITU-T series M.30.

The OSS is the functional entity from which the

network operator monitors and controls the system. The purpose

of OSS is to offer the customer cost-effective support for

centralized, regional and local operational and maintenance

activities that are required for a GSM network. An important

function of OSS is to provide a network overview and support

the maintenance activities of different operation and

maintenance organizations.

THE GSM SPECIFICATIONS

Specifications for different Personal Communication

Services (PCS) systems vary among the different PCS networks.

The GSM specification is listed below with important

characteristics.

Modulation

Modulation is a form of change process where we change

the input information into a suitable format for the transmission

medium. We also changed the information by demodulating the

signal at the receiving end.

The GSM uses Gaussian Minimum Shift Keying (GMSK) modulation method.

Access Methods

Because radio spectrum is a limited resource shared by

all users, a method must be devised to divide up the bandwidth

among as many users as possible.

GSM chose a combination of TDMA/FDMA as its

method. The FDMA part involves the division by frequency of

the total 25 MHz bandwidth into 124 carrier frequencies of 200

kHz bandwidth.

One or more carrier frequencies are then assigned to

each BS. Each of these carrier frequencies is then divided in

time, using a TDMA scheme, into eight time slots. One time slot

is used for transmission by the mobile and one for reception.

They are separated in time so that the mobile unit does not

receive and transmit at the same time.

Transmission Rate

The total symbol rate for GSM at 1 bit per symbol in

GMSK produces 270.833 K symbols/second. The gross

transmission rate of the time slot is 22.8 Kbps.

GSM is a digital system with an over-the-air bit rate of 270

kbps.

Frequency Band

The uplink frequency range specified for GSM is 933 -

960 MHz (basic 900 MHz band only). The downlink frequency

band 890 - 915 MHz (basic 900 MHz band only).

Channel Spacing

This indicates separation between adjacent carrier

frequencies. In GSM, this is 200 kHz.

Speech Coding

GSM uses linear predictive coding (LPC). The purpose

of LPC is to reduce the bit rate. The LPC provides parameters

for a filter that mimics the vocal tract. The signal passes through

this filter, leaving behind a residual signal. Speech is encoded at

13 kbps.

Duplex Distance

The duplex distance is 80 MHz. Duplex distance is the

distance between the uplink and downlink frequencies. A

channel has two frequencies, 80 MHz apart.

Misc

Frame duration: 4.615 ms

Duplex Technique: Frequency Division Duplexing (FDD)

access mode previously known as WCDMA.

Speech channels per RF channel: 8.

GSM - ADDRESSES AND IDENTIFIERS

GSM distinguishes explicitly between user and

equipment and deals with them separately. Besides phone

numbers and subscriber and equipment identifiers, several other

identifiers have been defined; they are needed for the

management of subscriber mobility and for addressing of all the

remaining network elements. The most important addresses and

identifiers are presented in the following:

International Mobile Station Equipment Identity (IM EI)

The international mobile station equipment identity (IMEI)

uniquely identifies a mobile station internationally. It is a kind

of serial number. The IMEI is allocated by the equipment

manufacturer and registered by the network operator and

registered by the network operator who stores it in the EIR. By

means of IMEI one recognizes obsolete, stolen or nonfunctional

equipment.

International Mobile Subscriber Identity (IMSI)

Each registered user is uniquely identified by its

international mobile subscriber identity (IMSI). It is stored in the

subscriber identity module (SIM) a mobile station can only be

operated if a SIM with a valid IMSI is inserted into equipment

with a valid IMEI.

SECURITY AND ENCRYPTION

The security methods standardized for the GSM

System make it the most secure cellular telecommunications

standard currently available. Although the confidentiality of a

call and anonymity of the GSM subscriber is only guaranteed on

the radio channel, this is a major step in achieving end-to- end

security.

The subscriber's anonymity is ensured through the use

of temporary identification numbers. The confidentiality of the

communication itself on the radio link is performed by the

application of encryption algorithms and frequency hopping

which could only be realized using digital systems and

signaling.

Mobile Station Authentication

The GSM network authenticates the identity of the

subscriber through the use of a challenge-response mechanism.

A 128-bit random number (RAND) is sent to the MS. The MS

computes the 32-bit signed response (SRES) based on the

encryption of the random number (RAND) with the

authentication algorithm (A3) using the individual subscriber

authentication key (Ki). Upon receiving the signed response

(SRES) from the subscriber, the GSM network repeats the

calculation to verify the identity of the subscriber.

The individual subscriber authentication key (Ki) is

never transmitted over the radio channel. It is present in the

subscriber's SIM, as well as the AUC, HLR, and VLR databases

as previously described. If the received SRES agrees with the

calculated value, the MS has been successfully authenticated

and may continue. If the values do not match, the connection is

terminated and an authentication failure indicated to the MS.

The calculation of the signed response is processed

within the SIM. This provides enhanced security, because the

confidential subscriber information such as the IMSI or the

individual subscriber authentication key (Ki) is never released

from the SIM during the authentication process.

Signaling and Data Confidentiality

The SIM contains the ciphering key generating

algorithm (A8) which is used to produce the 64-bit ciphering

key (Kc). The ciphering key is computed by applying the same

random number (RAND) used in the authentication process to

the ciphering key generating algorithm (A8) with the individual

subscriber authentication key (Ki). As will be shown in later

sections, the ciphering key (Kc) is used to encrypt and decrypt

the data between the MS and BS.

An additional level of security is provided by having

the means to change the ciphering key, making the system more

resistant to eavesdropping. The ciphering key may be changed at

regular intervals as required by network design and security

considerations. In a similar manner to the authentication process,

the computation of the ciphering key (Kc) takes place internally

within the SIM. Therefore sensitive information such as the

individual subscriber authentication key (Ki) is never revealed

by the SIM.

Encrypted voice and data communications between the

MS and the network is accomplished through use of the

ciphering algorithm A5. Encrypted communication is initiated

by a ciphering mode request command from the GSM network.

Upon receipt of this command, the mobile station begins

encryption and decryption of data using the ciphering algorithm

(A5) and the ciphering key (Kc).

Subscriber Identity Confidentiality

To ensure subscriber identity confidentiality, the

Temporary Mobile Subscriber Identity (TMSI) is used. The

TMSI is sent to the mobile station after the authentication and

encryption procedures have taken place. The mobile station

responds by confirming reception of the TMSI. The TMSI is

valid in the location area in which it was issued. For

communications outside the location area, the Location Area

Identification (LAI) is necessary in addition to the TMSI.

Telephony Service

These services can be charged on per call basis. Only call

initiator has to pay the charges and now a day, all the incoming

charges are free. A customer can be charged based on different

parameters like:

International call or long distance call.

Local call

Call made during peak hours.

Call made during night time

Discounted call during weekends.

Call per minute or per second.

Many more other criteria can be designed by a service

provider to charge their customers.

SMS Service

Till the time this tutorial is written, most of the service

providers are charging their customer's SMS services based on

number of text messages sent from their mobile phone. There

are other prime SMS services available where service providers

are charging more than normal SMS charge. These services are

being used in collaboration of Television Networks or Radio

Networks to demand SMS from the audiences

Most of time charges are paid by the SMS sender but

for some services like stocks and share prices, mobile banking

facilities and leisure booking services etc. recipient of the SMS

has to pay for the service.

GPRS Services

Using GPRS service we can browse Internet and can play

games on the Internet, we can download movies or music etc. So

a service provider will charge us based on the data uploaded as

well as data downloaded on our mobile phone. These charges

will be based on per Kilo Byte data downloaded/uploaded.

Additional parameter could be a Quality of Service

provided to us. If we want to watch a movie then a low quality

may work because some data loss may be acceptable to us but if

we are downloading a zip file then a single byte loss will corrupt

our complete downloaded file.

Advantages of GSM

GSM is already used worldwide with over 450 million

subscribers.

International roaming permits subscribers to use one phone

throughout Western Europe. CDMA will work in Asia, but

not France, Germany, the U.K. and other popular European

destinations.

GSM is mature, having started in the mid-80s. This

maturity means a more stable network with robust features.

CDMA is still building its network.

LCD PIN DESCRIPTIONS

Fig 1. Shows the pin diagram of a 14 pin LCD.

The LCD used here has 14 pins. The functions of each pin is

given below:

VCC, VSS, and VEE :

LCD PIN DESCRIPTIONS

Fig 1. Shows the pin diagram of a 14 pin LCD.


VCC, VSS, and VEE :


While Vcc and Vss provide +5V and ground, respectively, VEE

is used for controlling LCD contrast.

RS, REGISTER SELECT:

There are two very important registers inside the LCD. The RS

pin is used for their selection as follows .If RS = 0 , then

instruction command code register is selected , allowing the user

to send the command such as clear display, cursor at home, etc.

If RS = 1 the data register is selected, allowing the user to send

data to be displayed on the LCD.

R/W, READ/WRITE:

R/W input allows the user to write information to the LCD or

read information from it.

R/W =1 when reading ; R/W = 0 when writing.

E, ENABLE:

The enable pin is used by the LCD to latch information

presented to its data pins. When data is supplied to data pins, a

high – to – low pulse must be applied to this pin in order for the

LCD to latch in the data present at the data pins. This pulse must

be a minimum of 450 ns wide.

D0 – D7:

The 8 – bit data pins , D0 – D7, are used to send information to

the LCD or read the contents of the LCD's internal registers.

To display letters and numbers, we send ASCII codes for the

letters A- Z, a-z, and 0-9 to these pins while making RS = 1.

There are also instruction command codes that can be send to

the LCD to clear the display or force to cursor to the home

position or blink the cursor.

We also use RS=0 to check the busy flag bit to see if the LCD is

ready to receive information. The busy flag is D7 and can be

read when R/W=1.RS=0, as follows: if R/W=1 and RS=0.When

D7=1 (busy flag=1), the LCD is busy taking care of internal

operations and will not accept any new information. When D7

= 0, the LCD is ready to receive new information.

PIN DESCRIPTION FOR LCD

Pi

n

Sym

bol

I/O Description

1 Vss -- Ground

2 Vcc -- +5V power supply

3 VE

E

-- Power supply to control contrast

4 RS I RS=0 for command register, RS=1 for

data register

5 R/W I R/W+0 for write, R/W+1 for read

6 E I/O Enable

7 DB0 I/O The 8-bit data bus








LCD Command Codes

Code (Hex) Command to LCD Instruction

Register

1 Clear display screen

2 Return home

4 Decrement cursor(shift cursor to left)

6 Increment cursor(shift cursor to right)

5 Shift display left

7 Shift display left

8 Display off, cursor off

A Display off, cursor on

C Display on, cursor off

E Display on

F Display on, cursor blinking

10 Shift cursor position to left

14 Shift cursor position to right

18 Shift the entire display to the left

1C Shift the entire display to the right

80 Force cursor to beginning of first line

C0 Force cursor to beginning of second

line

38 2 lines and 5x7 matrix

WORKING:

The interface used by LCD is a parallel bus, allowing simple and

fast reading/writing of data to and from the LCD.

.

This waveform will write an ASCII Byte out to the LCD's

screen. The ASCII code to be displayed is eight bits long and is

sent to the LCD either four or eight bits at a time. If four bit

mode is used, two "nibbles" of data (Sent high four bits and then

low four bits with an "Enable" Clock pulse with each nibble) are

sent to make up a full eight bit transfer. The "Enable" Clock is

used to initiate the data transfer within the LCD.

Sending parallel data as either four or eight bits are the two

primary modes of operation. While there are secondary

considerations and modes, deciding how to send the data to the

LCD is most critical decision to be made for an LCD interface

application.

Eight bit mode is best used when speed is required in an

application and at least ten I/O pins are available. Four bit mode

requires a minimum of six bits. To wire a microcontroller to an

LCD in four bit mode, just the top four bits (DB4-7) are written

to.

The "RS" bit is used to select whether data or an instruction is

being transferred between the microcontroller and the LCD. If

the Bit is set, then the byte at the current LCD "Cursor" Position

can be read or written. When the Bit is reset, either an

instruction is being sent to the LCD or the execution status of

the last instruction is read back (whether or not it has

completed).

Reading Data back is best used in applications which required

data to be moved back and forth on the LCD (such as in

applications which scroll data between lines).In our Project we

have permanently grounded R/W pin which means we are not

retrieving any data from LCD.

The LCD can be thought of as a "Teletype" display because in

normal operation, after a character has been sent to the LCD, the

internal "Cursor" is moved one character to the right. The "Clear

Display" and "Return Cursor and LCD to Home Position"

instructions are used to reset the Cursor's position to the top

right character on the display.

To move the Cursor, the "Move Cursor to Display" instruction is

used. For this instruction, bit 7 of the instruction byte is set with

the remaining seven bits used as the address of the character on

the LCD the cursor is to move to. These seven bits provide 128

addresses, which matches the maximum number of LCD

character addresses available.

Eight programmable characters are available and use codes

0x000 to 0x007. They are programmed by pointing the LCD's

"Cursor" to the Character Generator RAM

The last aspect of the LCD to discuss is how to specify a

contrast voltage to the Display. I typically use a potentiometer

wired as a voltage divider. This will provide an easily variable

voltage between Ground and Vcc, which will be used to specify

the contrast (or "darkness") of the characters on the LCD screen.

You may find that different LCDs work differently with lower

voltages providing darker characters in some and higher

voltages do the same thing in others

CIRCUIT DIAGRAM OF LCD INTERFACING

DC Motor

DC Motor has two leads. It has bidirectional motion

• If we apply +ve to one lead and ground to another motor

will rotate in one direction, if we reverse the connection the

motor will rotate in opposite direction.

• If we keep both leads open or both leads ground it will not

rotate (but some inertia will be there).

• If we apply +ve voltage to both leads then braking will

occurs.

H-Bridge

This circuit is known as H-Bridge because it looks like ”

H”

Working principle of H-Bridge

• If switch (A1 and A2 )are on and switch (B1 and

B2) are off then motor rotates in clockwise

direction

• If switch (B1 and B2 )are on and switch (A1 and

A2) are off then motor rotates in Anti clockwise

direction

• we can use Transistor, mosfets as a switch ( Study

the transistor as a a switch)

H-Bridge I.C (L293D)

L293D is a H-Bridge I.C. Its contain two H-Bridge pair.

Truth Table

Input 1 Input 2 Result

0 0 No rotation

0 1 Clockwise rotation

1 0 Anti clockwise

rotation

1 1 Break

Note:-

• Connect motors pins on output 1 and output 2 and control

signal at input 1 and input 2 will control the motion

• Connect another motor pins on output 3 and output 4 and

control signal at input3and input 4

• Truth table for i/p 3 and i/p 4 is same as above shown

• 0 means 0 V or Low

• 1 means High or +5V

• In Enable 1 and Enable 2 if you give high then you observe

hard stop in condition 0 0 and 11. Unless slow stop of

motor on low signal

• Required Motor voltage has given on pin 8 (Vs) i.e 12V

DC – 24V DC

SYSTEMATIC OF L293D WITH DC GEARED MOTOR

+ 15 V DC

MOTOR VOLTAGE

L293D

27

1015

19

361114

168

IN1IN2IN3IN4

EN1EN2

OUT1OUT2OUT3OUT4

VSSVS

+5V DC

DUAL H-BRIDGE

+ 5 V DC

DC MOTOR

12

DC MOTOR

12

µVISION

The µ Vision IDE is, for most developers, the easiest way to

create embedded system programs. This chapter describes

commonly used µ Vision features and explains how to use them.

General Remarks and Concepts

Before we start to describe how to use µVision, some general

remarks, common to many screens1 and to the behavior of the

development tool, are presented. In our continuous effort to

deliver best-in-class development tools, supporting you in your

daily work, µVision has been built to resemble the look-and-feel

of widespread applications. This approach decreases your

learning curve, such that

you may start to work with µ Vision right away.

Based on the concept of windows:

µ Vision windows can be re-arranged, tiled, and attached to

other screen areas or windows respectively It is possible to drag

and drop windows, objects, and variables

A Context Menu, invoked through the right mouse button, is

provided for most objects. You can use keyboard shortcuts and

define your own shortcuts. You can use the abundant features of

a modern editor. Menu items and Toolbar buttons are greyed out

when not available in the Current context.

Graphical symbols are used to resemble options, to mark

unsaved changes, or reveal objects not included into the project.

Status Bars display context-driven information.You can

associate µVision to third-party tools

The Project Windows area is that part of the screen in which,

by default, the Project Window, Functions Window, Books

Window, and Registers Window are displayed.

Within the Editor Windows area, you are able to change the

source code, view performance and analysis information, and

check the disassembly code.

The Output Windows area provides information related to

debugging, memory, symbols, call stack, local variables,

commands, browse information, and find in files results.

If, for any reason, you do not see a particular window and have

tried displaying/hiding it several times, please invoke the default

layout of µVision through the Window – Reset Current

Layout Menu.

Positioning Windows

The µVision windows may be placed onto any area of the

screen, even outside of the µVision frame, or to another physical

screen.

Click and hold the Title Bar1 of a window with the left mouse

button

Drag the window to the preferred area, or onto the preferred

control, and release the mouse button

Please note, source code files cannot be moved outside of the

Editor Windows2.\ Invoke the Context Menu of the window’s

Title Bar to change the docking attribute of a window object. In

some cases, you must perform this action before you can drag

and drop the window.

µVision displays docking helper controls3, emphasizing the area

where the window will be attached. The new docking area is

represented by the section highlighted in blue. Snap the window

to the Multiple Document Interface (MDI) or to a Windows area

by moving the mouse over the preferred control.

Keil software converts the C-codes into the Intel Hex code.

A view of Keil uVision 3

A view of Keil uVision 3

8051 Burner Software

PRO51 BURNER provides you with software burning tools for

8051 based Microcontrollers in there Flash memory. The 51

BURNER tools, you can burn AT89SXXXX series of ATMEL

microcontrollers.

PRO 51

PRO51 - Programmer for C51 family

Features of PRO51

• Flash Programmer for 89C1051, 89C2051, 89C4051, 89S51,

89S52, 89C51 and 89C52 micros.

• Operates on single 5V supply which can be taken from USB

Port of PC.

• User friendly windows based Graphics User Interface.

• Interfaces with PC through COM1 or COM2 serial ports.

System Requirements

• PC with at least one serial and one USB ports and at least

600x800 VGA resolution.

• If USB port is not available you need a regulated +5V supply.

• Windows operating system

Package Contents

• PRO51 unit

• Interface Cable between PC and PRO51

• CD containing PROG51 software

Getting Started

1. Install PROG51 programs using setup from the CD. This would

normally create these programs in a program group INFONICS.

You may like to create a separate folder like INFONICS on your

disk where these programs will be installed.

2. Connect PRO51 to COM port and USB on your PC using the Y

cable provided with PRO51. Follow instruction given in the

following sections.

PROG51 User Interface

Prog51 is used for programming the 89C1051, 89C2051 and

89C4051 Microcontrollers. User interface includes:

• Load Hex/Binary file in Buffer

• Save Buffer as Binary File

• Display / Specify Target Device to be Programmed.

• Com Port Selection.

• Identify Target Device with the device specified by you in the

designated area.

• Read Microcontroller Program in Buffer

• Erase Microcontroller Program Memory

• Check if Target Device is Erased

• Program Buffer Contents in Target device

• Verify the Device contents with data in the buffer

3. Lock Target Device. Once the device is locked it can not be read

or verified.

Procedure to Program a Chip

1. Connect the PRO51 to COM port and USB port on your PC.

USB is used for +5V power supply only. You can use regulated

5V supply and connect it on pin 4 of the 9 Pin connector.

2. Start PROG51 from your program menu.

3. Select appropriate com port on your PC.

4. Insert desired device in the ZIF socket on PRO51. 20 Pin

devices like 89C2051 should be aligned with the bolltom side,

i.e., pin 10 on the 89C2051 should be inserted in Pin 20 of the

socket.

5. Specify the device in the target device text box.

6. Click Identify button to check if the device inserted matches

with the one you specified in the Target Device text box.

7. Load Hex or Binary file generated using compiler or assembler

in the buffer.

8. Click on Erase button to erase the contents of the flash memory

of the microcontroller. Erase process will automatically be

followed by a blank check.

9. Click on Program button to write the buffer contents in to the

program memory of the microcontroller. Program action will

automatically be followed by a verify cycle.

10. If you wish click on Lock button to secure the device.

11. Remove the device from ZIF socket.

Fig 1. Block Diagram of PRO51

ZIF Socket

RST RXD TXD

Programmer

Power

Supply

3

2

6

8

4

5

Pin description of 9 PIN male connector on PRO51

Pin Name Description

1 NC Not connected

2 RXD Serial Port Receive Data. This pin should

be connected to TXD pin of COM port on

PC.

3 TXD Serial Port Transmit Data. This pin should

be connected to RXD pin of COM port on

PC.

4 VCC +5V supply for the PRO51. It must be

regulated supply. Cable supplied with the

device draws power from the USB port of

your PC. If you wish to use any other

source of power the same should be

connected to this pin.

5 GND Signal and power ground for serial port

and 5V power supply.

6 RXDEN If this pin is left open or pulled up (>3V)

then RXD signal received at PIN 2 above

is sent to the CPU. If you wish to disable

the RXD signal then this PIN should be

pulled –Ve. With the standard cable

supplied by Infonics this pin is connected

to the DSR signal of COM port.

Therefore, the DSR must high to enable

the RXD.

7 NC Not connected

8 RESET A high (> 3V) on this pin will reset the

PRO51. With the standard cable supplied

by Infonics this pin is connected to the

RTS signal of COM port. Therefore, the

RTS must be kept low for proper

operation of the PRO51. A high pulse on

RTS can be used to reset the device.

9 NC Not connected

CONSTRUCTION AND TESTING

CONSTRUCTION

In the process of realizing this project, the construction was

initially carried out on a breadboard to allow for checking and to

ascertain that it is functioning effectively. All irregularities were

checked then tested and found to have a satisfactory output. The

component were then removed and transferred to a Vero board

strip and soldered into place and all discontinuous point were cut

out to avoid short-circuiting.

PRECAUTIONS

SOLDERING PRECAUTIONS

The construction was carried out with care. The precautions

taken during the soldering were:

• The tip of soldering iron was kept clean with the help of a file

from time to time.

• The solder wire was of smaller thickness.

• Extra solder was not used in order to avoid a cause of short

circuit in the conductive path.

• The overheating of components was avoided to prevent

component damage as a result of excessive heat on the

components due to the heat from the soldering iron.

• The leads of the components were kept clean before soldering,

with the use of sand paper.

COMPONENTS PRECAUTION:

• IR sensor used should be sensitive. Before using in the

circuit it should be tested with a multi-meter.

• I.C should not be heated much while soldering; too much

heat can destroy the I.C. For safety and ease of

replacement, the use of I.C socket is suggested.

• While placing the I.C pin no 1 should be made sure at

right hole.

• Opposite polarity of battery can destroy I.C so please

check the polarity before switching ON the circuit. One

should use diode in series with switch for safety since

diode allows flowing current in one direction only.

• Each component was soldered neatly and clean.

• We should use insulated wires.

TESTING OF PROJECT

With the knowledge of operation of the system was tested step

by step to the transistor output and the load was connected

across the collector terminal of the transistor.

ASSEMBLING

The whole system was packed in a plastic casing and provision

was made for the IR to sense light from the outside.

REFERENCES

“8051 and embedded system” by Mazidi and Mazidi

All datasheets from www.datasheetcatalog.com

About AT89s8252 from www.atmel.com

And www.triindia.co.in

Date post:	22-Jan-2016
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