Report Matter

8/2/2019 Report Matter

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CHAPTER 1

INTRODUCTION

New generation of cars are improved in such a way that the number of accidents decreases.

Innovative ideas has implemented and emerged in order to reduce the risk of accident. During the

recent past years, some alarm system and intelligent controlled apparatus have been designed and

developed in order to increase the safety of automobiles. Security in travel is primary concern for

everyone.

This Project describes a design of effective alarm system that can monitor an automotive /

vehicle / car condition in travelling. The project name ACCIDENT ALERT WITH

AUTOMATIC DIALLER shows that project is designed to prevent the accident and to informemergency about an accident that has occurred.

This project uses a glass breakage sensor that detects breakage of glass and smoke detector

that detects any smoke due to fire in the vehicle. These sensors send a signal to microcontroller. A

DTMF dialer is connected to the microcontroller. A basic telephone unit is interfaced to the DTMF

dialer chip that sends call to the predefined mobile or emergency number and informs about this

accident.

Sometimes, vehicles large in size (i.e. trucks, loading vehicles) have problems in driving

the vehicle. There are some points which are not visible from drivers seat, these are called blind

points. Some time, objects or vehicles very near to truck got accident. This problem is called blind

spot.

Some time due to fog vehicles are not visible up to very less distance, an accident can

occur due to this. While driving at night there can be a short nap to driver due to which accident can

occur. Sometimes there are 4 wheelers having one headlight not working due to this they appear to

be 2 wheelers and tend to cause accidents. To prevent the vehicle from accident, proximity detector

used in this project that detect an object through its range and alert the driver.


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CHAPTER 2

CONSTRUCTION AND WORKING

The project ACCIDENT ALERT WITH AUTOMATIC DIALLER used to prevent

accident and alert the driver and emergency about accident. The construction and working of the

project can be shown as a block diagram given below.

2.1 Block Diagram

Fig. 2.1 Block diagram of PROJECT

Fig. 2.2 PCB LAYOUT


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Fig. 2.3 Circuit Diagram of Dialer Circuit with Detectors and

Power supply system


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Fig. 2.4 IR circuit


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The block diagram shows the main contents used in project. The project includes 9 volt power

supply system that provides power supply to the project. At the input of microprocessor, three

detector circuits used to apply and according to their output alarm and dialer circuit works.

The main contents of the project taking part in construction are:-

1. Power supply system

2. Transformer

3. Various sensors used in project

4. Buffer IC

5. Microcontroller

6. Dialer system

2.2.1 POWER SUPPY SYSTEM

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.

2.2.1.1 Types of Power Supply

There are many types of power supply. Most are designed to convert high voltage AC

mains electricity to a suitable low voltage supply for electronic circuits and other devices. A power

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

Some electronic circuits require a power supply with positive and negative outputs as well

as zero volts (0V). This is called a 'dual supply' because it is like two ordinary supplies connected

together.

Each of the blocks is described in more detail below:

Transformer - steps down high voltage AC mains to low voltage AC.

RectifierBridge rectifierA bridge rectifier can be made using four individual diodes, but it is also available in

special packages containing the four diodes required. It is called a full-wave rectifier because it uses

the entire AC wave (both positive and negative sections). 1.4V is used up in the bridge rectifier

because each diode uses 0.7V when conducting and there are always two diodes conducting, as

shown in the diagram below.

Bridge rectifiers are rated by the maximum current they can pass and the maximum reverse

voltage they can withstand (this must be at least three times the supply RMS voltage so the rectifier

can withstand the peak voltages).


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Please see the Diodes page for more details, including pictures of bridge rectifiers.

Fig. 2.6 Bridge rectifier and output

Smoothing :-

Smoothing is performed by a large value electrolytic capacitor connected across the DC

supply to act as a reservoir, supplying current to the output when the varying DC voltage from the

rectifier is falling. The diagram shows the Unsmoothed varying DC (dotted line) and the smoothed

DC (solid line). The capacitor charges quickly near the peak of the varying DC, and then discharges

as it supplies current to the output.

Fig. 2.7 circuit of smoothing and output

Regulator :-

Voltage regulator ICs are available with fixed (typically 5, 12 and 15V) or variable

output voltages. They are also rated by the maximum current they can pass. Negative voltage

regulators are available, mainly for use in dual supplies.

Most regulators include some automatic protection from excessive current ('overload

protection') and overheating ('thermal protection').


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Many of the fixed voltage regulator ICs has 3 leads and look like power transistors, such

as the 7805 +5V 1A regulator shown on the right. They include a hole for attaching a heat sink if

necessary.

Fig. 2.8 circuit of regulator

The power supply circuit diagram used in project is given below:-

Fig.2.9 Power supply circuit diagram

2.2.2 TRANSFORMER

Transformers convert AC electricity from one voltage to another with little loss of power.

Transformers work only with AC and this is one of the reasons why mains electricity is AC. Step-up

transformers increase voltage, step-down transformers reduce voltage. Most power supplies use a

step-down transformer to reduce the dangerously high mains voltage (230V in UK) to a safer low

voltage.


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There is no electrical connection between the two coils; instead they are linked by an

alternating magnetic field created in the soft-iron core of the transformer. The two lines in the

middle of the circuit symbol represent the core. Transformers waste very little power so the power

out is (almost) equal to the power in. Note that as voltage is stepped down current is stepped up.

The ratio of the number of turns on each coil, called the turns ratio, determines the ratio

of the voltages. A step-down transformer has a large number of turns on its primary (input) coil

which is connected to the high voltage mains supply, and a small number of turns on its secondary

(output) coil to give a low output voltage.

2.2.3 VARIOUS SENSORS USED IN PROJECT

A sensor is a device which measures a physical quantity and converts it into a signal

which can be read by an observer or by an instrument. For example, a mercury thermometer converts

the measured temperature into expansion and contraction of a liquid which can be read on a

calibrated glass tube. A thermocouple converts temperature to an output voltage which can be read

by a voltmeter. For accuracy, all sensors need to be calibrated against known standards.

The sensors used in project are given below:-

1. Smoke detector

2. Proximity sensor

3. Glass breakage detector

2.2.3.1SMOKE DETECTOR

As it is mentioned previously that smoke detector is a circuit that used to detect any

smoke in the particular range. Smoke detector circuit uses an IC 555 that is a timer IC.

This circuit uses a very simple approach to detecting smoke in the air. It uses an LDR

(Light Dependent Resistor) as a light detector. As fire smoke comes across the LDR range, the

resistance of the LDR changes, which in turn trigger an alarm.

(a)SMOKE DETECTOR CIRCUIT


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Fig. 2.10 Smoke detector circuit

(b)IC DISCRIPTION

The NE555 is a highly stable controller capable of producing accurate timing pulses. With

monostable operation, the time delay is controlled by one external resistor and capacitor.

With astable operation, the frequency and duty cycle is accurately controlled with two

external resisters and one capacitor.

(c)Features

High Current Drive Capability (200mA)

Adjustable Duty Cycle

Temperature Stability of 0.005%/ C

Timing From sec to Hours

Turn off Time Less Than 2 sec


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(d)Applications

Monostable Operation

Astable Operation

Frequency divider

Pulse Width Modulation

Pulse Position Modulation

Linear Ramp

(e)LIGHT DEPANDENT RESISTOR (LDR)

A light-dependent resistor, alternatively called an LDR, is a variable resistor whose

value decreases with increasing incident light intensity. An LDR used in circuit, is made of a high-

resistance semiconductor. If light falling on the device is of high enough frequency, photons

absorbed by the semiconductor give bound electrons enough energy to jump into the conduction

band. The resulting free electron (and its hole partner) conduct electricity, thereby lowering

resistance. In the circuit, as the LDR detect the light variations due to smoke, it gives the output to

the IC555 and timer IC produce a trigger .

a Light dependent resistors have a particular property in that they remember the lighting conditions

in which they have been stored. This memory effect can be minimized by storing the LDRs in light

prior to use.

Light storage reduces equilibrium time to reach steady resistance value. LDRs have wide

spectral response. They have low cost and the optimum temperature range is wide. Hence these are

commonly used in circuits like light operated relays, automatic light control etc. From the above

discussion, it is clear that the smoke detector circuit detects the smoke and gives the trigger alarm to

the output.

2.2.3.2 PROXIMITY SENSOR

The proximity sensor used in the project is a long range IR transmitter circuit. This is an

ULTRASONIC SENSOR work on a principal similar to radar. Here a detector circuit is used that

will give long range detection.


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Fig. 2.11 Proximity sensor circuit

(a)CIRCUIT DISCRIPTION

The circuit uses three infrared transmitting LEDs (IR1, IR2, and IR3) in series to increase

the radiated power. Further to increase directivity and power density, in circuit, IR LEDs inside the

reflector of torch can assemble.

For increasing the efficiency a MOSFET (BS170) is used, which acts as a switch and

thus reduce the power loss that would result if a transistor were used. To avoid any dip during its

ON/OFF operation, a 100F reservoir capacitor C2 is used across the power supply. Capacitor C2

supplies extra charge during switch on operation. As the MOSFET exhibits large capacitance across

gate source terminals, a special drive arrangement has been made using NPN-PNP DARLINGTON

PAIR of BS547 and BS557 (as emitter follower), to avoid the distortion to the gate drive input.

Data to be transmitted is used for modulating the 38 kHz frequency generator by CD4047 (IC1).

In the receiver section, TSOP1738 is used for efficient reception. The transmitter

circuit transmit the IR waves towards the target and in receiver section, receiver receive the IR

signals with variations and give suitable output to the microprocessor.


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(b)TSOP1738

The TSOP1738 is miniaturized receiver for infrared remote control system. Pin diode and

preamplifiers are assembled on lead frame, the epoxy package is designed as IR filter. The

demodulated output signal can directly be decoded by a microprocessor. TSOP1738 Series is

standard IR control receiver series, supporting all major transmission codes.

(c)FEATURES

Photo detector and preamplifier in one package

Internal filter for PCM frequency

Improved shielding against electric field disturbance

TTL and CMOS compatibility

Active low output

Low power consumption

High immunity against ambient light

Continuous data transmission possible

2.2.3.3 GLASS BREAKAGE DETECTOR

Schematic diagram of glass breakage detector is shown in the fig. below:-

Fig: 2.12 Glass breakage detector


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A switch is fitted in closed condition below glass. As far as switch is closed current is

flowing through resistor R and output is 1. When glass breakage occurs, switch gets open and output

is 0, which is detected by microcontroller. According to the output of glass breakage detector,

microcontroller gives automatic dialing.

2.2.4BUFFER IC

The project use buffer IC LM324 to make compatibility of the circuit with

microcontroller 8051. The LM324 consists of four independent, high gains; internally frequency

compensated operational amplifiers which were designed specifically to operate from a single power

supply over a wide range of voltages.

FIG. 2.13 Buffer IC PIN configurations

(a)Features

Internally frequency compensated for unity gain

Large DC voltage gain 100 dB

Wide bandwidth (unity gain) 1 MHz (temperature compensated)

Wide power supply range: Single supply 3V to 32V or dual supplies 1.5V to 16V

Very low supply current drain (700 A)-essentially independent of supply voltage

Low input biasing current 45 nA (temperature compensated)

Low input offset voltage 2 mV and offset current: 5 nA

Input common-mode voltage range includes ground

Differential input voltage range equal to the power supply voltage

Large output voltage swing 0V to V+ - 1.5V

2.2.5 MICROCONTROLLER


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Microcontroller is a on-chip computer or single chip computer. This small device is

used to control event, processes and objects. Another term to describe micro-controller is embedded

controller because the microcontroller and its support circuits are often built into, or embedded in,

devices they control.

Any device that measures, stores, controls, calculates and displays information is a candidate

for putting microcontroller inside. Microcontroller contains memory, I/O interfaces in addition to the

C.P.U. Because the amount of memory and interfaces is limited so microcontrollers are used for

smaller system.

In this project, microcontroller 8051 is used.

2.2.5.1MICROCONTROLLER 8051:

(a)Features

Internal ROM and RAM

I/O ports with programmable pins

Timers and counters

Serial data communication

(b)PIN DISCRIPTION

VCC - Supply voltage

GND - Ground

PORT 1 - Port 1 is an 8 bit bi directional I/O port. Port pins p1.2 to P1.7 provides internal pull -

ups. P1.0 and P1.1 require external pull- ups. P1.0 and P1.1 also serves as positive input and

negative input.

PORT 3 - Port 3 pins P3.0 to P3.5, P3.7 are seven bi directional I/O pins with internal pull-ups.P3.6

is hard wired as an input to output of the on chip comparator and is not accessible with general

purpose I/O pin.

(c)Port pin Alternate function

P3.0 RXD (SERIAL INPUT PORT)

P3.1 TXD (SERIAL OUTPUT PORT)

P3.2 INT 0 (INTERNAL INTERRUPT 0)


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P3.3 INT 1 (EXTERNAL INTERRUPT 1)

P3.4 T 0 (TIMER 0)

P3.5 T 1 (TIMER 1)

TABLE 2.2 PIN FUNCTIONS OF MICROCONTROLLER 8051

Port 3 also receives some control signals for flash programming and verification.

RST - Reset input.

XTAL1 - Input to the inverting oscillator amplifier and input to the internal Clock operating circuit.

XTAL2 - Output from inverting oscillator amplifier.


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FIG.2.14 Block Diagram of MICROCONTROLLER 8051


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(d)MICROCONTROLLER CODE OF PROJECT

#include

void main()

{

unsigned int detect;

PORTB.bit0=0;

PORTB.bit1=0;

PORTB.bit2=0;

PORTB.bit3=0;

detect=0;

Lcd_Initialize(&PORTC);

Lcd_Command(Lcd_CLEAR);

Lcd_Command(Lcd_CURSOR_OFF);

Lcd_Output(1, 1, " Accident Alarm");

Lcd_Output(2, 1, "Init......");

delay_ms(2000);

while(1)

{



Lcd_Output(2, 1, "Normal");


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if(PORTA.bit0==1)

{

detect=1;

}

if(PORTA.bit1==1)

{

detect=1;

}

if(PORTA.bit2==1)

{

detect=1;

}

if(PORTA.bit3==1)

{

detect=1;

}

if(detect==1)

{



Lcd_Output(2, 1, "Warning");

PORTB.bit0=1;


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PORTB.bit1=1;

PORTB.bit2=1;

PORTB.bit3=1;

delay_ms(5000);

PORTB.bit0=0;

PORTB.bit1=0;

PORTB.bit2=0;

PORTB.bit3=0;

detect=0;

}

delay_ms(100);

}

}


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2.2.6DIALER SYSTEM

Dialer system in this project is used to dial the number prescribed or predefined. As the

microcontroller produces the active output for dialer, to starts automatic dialing to the predefined

number that is store in the dialer system of project. DTMF dialer chip UM91214C is used in the

project for DTMF dialing.

2.2.6.1DTMF Dialer:

DTMF Dialer chip UM91214c is used for automatic dialing in this project.

FIG. 2.15 CONTROLLER DIAGRAM


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CHAPTER 3

BASIC ELECTRONIC COMPONENTS

3.1Resistors

FIGURE 2

Resistors are components that have a predetermined resistance. Resistance determines

how much current will flow through a component. Resistors are used to control voltages and

currents. A very high resistance allows very little current to flow. Air has very high resistance.

Current almost never flows through air. (Sparks and lightning are brief displays of current flow

through air. The light is created as the current burns parts of the air.) A low resistance allows a large

amount of current to flow. Metals have very low resistance. That is why wires are made of metal.

They allow current to flow from one point to another point without any resistance. Wires are usually

covered with rubber or plastic. This keeps the wires from coming in contact with other wires and

creating short circuits. High voltage power lines are covered with thick layers of plastic to make

them safe, but they become very dangerous when the line breaks and the wire is exposed and is no

longer separated from other things by insulation.

Resistance is given in units of ohms. (Ohms are named after Mho Ohms who played

with electricity as a young boy in Germany.)

Common resistor values are from 100 ohms to 100,000 ohms. Each resistor is marked

with colored stripes to indicate its resistance.


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3.2Variable Resistor

Variable resistors are also common components. They have a dial or a knob that allows

you to change the resistance. This is very useful for many situations. Volume controls are variable

resistors. When you change the volume you are changing the resistance which changes the current.

Making the resistance higher will let less current flow so the volume goes down. Making the

resistance lower will let more current flow so the volume goes up. The value of a variable resistor is

given as its highest resistance value. For example, a 500 ohm variable resistor can have a resistance

of anywhere between 0 ohms and 500 ohms. A variable resistor may also be called a potentiometer

(pot for short).

3.3Capacitors

FIGURE 3

Now suppose you want to control how the current in your circuit changes (or not

changes) over time. Now why would you?

Well radio signals require very fast current changes. Robot motors cause current

fluctuations in your circuit which you need to control. What do you do when batteries cannot supply


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current as fast as you circuit drains them? How do you prevent sudden current spikes that could fry

your robot circuitry? The solution to this is capacitors.

Capacitors are like electron storage banks. If your circuit is running low, it will deliver

electrons to your circuit.

In our water analogy, think of this as a water tank with water always flowing in, but with

drainage valves opening and closing. Since capacitors take time to charge, and time to discharge,

they can also be used for timing circuits. Timing circuits can be used to generate signals such as

PWM or be used to turn on/off motors in powered BEAM robots.

Quick note, some capacitors are polarized, meaning current can only flow one direction

through them. If a capacitor has a lead that is longer than the other, assume the longer lead must

always connect to positive.

3.4Power surge /drainage management

The problem with using robot components that drain a large amount of power issometimes your battery cannot handle the high drain rate, Motors and servos being perfect examples.

This would cause a system wide voltage drop, often resetting your microcontroller, or at least

causing it to not work properly.

Just a side note, it is bad to use the same power source for both your circuit and your

motors. Or suppose your robot motors are not operating at its full potential because the battery

cannot supply enough current, the capacitor will make up for it.

The solution is to place a large electrolytic capacitor between the source and ground of

your power source. Get a capacitor that is rated at least twice the voltage you expect to go through it.

Have it rated at 1mF-10mF for every amp required. For example, if your 20V motors will use 3

amps, use a 3mF-30mF 50V rated capacitor.

Exactly how much will depend on how often you expect your motor to change speed and

direction, as well as momentum of what you are actuating. Just note that if your capacitor is too

large, it may take a long time to charge up when you first turn your robot on.


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If it is too small, it will drain of electrons and your circuit will be left with a deficit. It is

also bad to allow a large capacitor to remain fully charged when you turn off your robot. Some

things could accidentally short and fry.

So use a simple power on LED in your motor circuit to drain the capacitor after your robot

is turned off. If your capacitor is not rated properly for voltage, then can explode with smoke.

Fortunately they do not overheat if given excessive amounts of current. So just make sure your

capacitor is rated higher than your highest expected.

Capacitors can also be used to prevent power spikes that could potentially fry circuitry.

Next to any on/off switch or anything that that could affect power suddenly should have a capacitor

across it?

Capacitors can eliminate switch bouncing. When you flip a mechanical switch, the switch

actually bounces several times within a microsecond range.

Normally this is too small of a time for anyone to care (or even notice), but note that a

microcontroller can take hundreds of readings in a single microsecond. So if your robot was

counting the number of times a switch is flipped, a single flip can count as dozens.

So how do you stop this? Use a small ceramic capacitor! Just experiment until you find the

power capacitance value.

3.5Diodes

FIGURE 4

Diodes are components that allow current to flow in only one direction. They have a

positive side (leg) and a negative side.

When the voltage on the positive leg is higher than on the negative leg then current flows

through the diode (the resistance is very low).


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When the voltage is lower on the positive leg than on the negative leg then the current

does not flow (the resistance is very high).

The negative leg of a diode is the one with the line closest to it. It is called the cathode.

The positive end is called the anode.

Usually when current is flowing through a diode, the voltage on the positive leg is 0.65

volts higher than on the negative leg.

3.6 Switches

Switches are devices that create a short circuit or an open circuit depending on the

position of the switch.

For a light switch, ON means short circuit (current flows through the switch, and lights

light up.) When the switch is OFF, that means there is an open circuit (no current flows, lights go

out.

When the switch is ON it looks and acts like a wire. When the switch is OFF there is no

connection.

3.7 LED

FIGURE 5

An LED is the device shown above. Besides red, they can also be yellow, green and

blue. The letters LED stand for Light Emitting Diode. The important thing to remember about diodes(including LEDs) is that current can only flow in one direction.

3.8Transistor

Transistors are basic components in all of today's electronics. They are just simple

switches that we can use to turn things on and off. Even though they are simple, they are the most

important electrical component.


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For example, transistors are almost the only components used to build a Pentium processor. A single

Pentium chip has about 3.5 million transistors. The ones in the Pentium are smaller than the ones we

will use but they work the same way.

Transistors that we will use in projects look like this:

FIGURE 6

The transistor has three legs, the Collector (C), Base (B), and Emitter (E). Sometimes they are

labeled on the flat side of the transistor.

Transistors always have one round side and one flat side. If the round side is facing you,

the Collector leg is on the left, the Base leg is in the middle, and the Emitter leg is on the right.

3.8.1Transistor Symbol

The following symbol is used in circuit drawings (schematics) to represent a transistor.

Basic Circuit

The Base (B) is the On/Off switch for the transistor. If a current is flowing to the Base,

there will be a path from the Collector (C) to the Emitter (E) where current can flow (The Switch If

there is no current flowing to the Base, then no current can flow from the Collector to the Emitter.

(The Switch is off.)


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Below is the basic circuit we will use for all of our transistors.

3.9POWER SUPPLY

Power supply can be defined as electronic equipment, which is a stable source of D.C.

power for electronic circuits.

Power supply can be classified into two major categories: -

Unregulated power supply

Regulated power supply

3.9.1UNREGULATED POWER SUPPLY: -

These power supplies, supply power to the load but do not take into variation of power

supply output voltage or current with respect to the change in A.C. mains voltage, load current or

temperature variations.

In other words, we can say that the output voltage or current of an unregulated power

supply changes with the change in A.C.mains voltage, load current and temperature.

3.9.2REGULATED POWER SUPPLY: -

These power supplies are regulated over the change in source voltage or load current i.e.

its output remains stable.

Regulated power supplies are of two types: -

3.9.2.1CURRENT REGULATED POWER SUPPLIES

These are constant current supplies in spite of change in load or input voltage.


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3.9.2.2VOLTAGE REGULATED POWER SUPPLIES

These supplies supply constant output voltage with respect to the variation in load or

source input voltage.

Fig. 2.16. BLOCK DIAGRAM OF REGULATED POWER SUPPLY

Fig. 2.17 CIRCUIT OF REGULATED POWER SUPPLY WITH HALF WAVE RECTIFIER

AND IC-7809 AS A REGULATOR

FIGURE 8

Here diode D1, D2, D3 and D4 forms half wave rectifier. Capacitor C1 is filteringcapacitor. IC-7809 is used for voltage regulation.

Capacitor C2 is used for bypassing, if any ripples are present then it eliminates those

ripples.

As IC-7809 is used so it gives 9v dc regulated voltage ideally. If we take 16 volts

transformer then we will get 8.97v at output. Thus voltage is regulated.

RECTIFIER FILTER REGULATOR LOADA.C.

Vac VL

C2

0.1uF

IN

COM

OUT

C1

1000uFD4D3D2D1

T1

10TO1 OUTPUT


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3.10Printed circuit boards

The use of miniaturization and sub miniaturization in electronic equipment design has

been responsible for the introduction of a new technique in inters component wiring and assembly

that is popularly known as printed circuit.

The printed circuit boards (PCBs) consist of an insulating substrate material with metallic

circuitry photo chemically formed upon that substrate. Thus PCB provides sufficient mechanical

support and necessary electrical connections for an electronic circuit.

Advantages of printed circuit boards: -

1) Circuits characteristics can be maintained without introducing variations inter

circuit capacitance.

2) Wave soldering or vapour phase reflow soldering can mechanize component

wiring and assembly.

3) Mass production can be achieved at lower cost.

4) The size of component assembly can be reduced with corresponding decrease in

weight.

5) Inspection time is reduced as probability of error is eliminated.

3.10.1Types of PCBs: -

There are four major types of PCBs: -

1) Single sided PCB: - In this, copper tracks are on one side of the board, and are the simplest

form of PCB. These are simplest to manufacture thus have low production cost.

2) Double sided PCB:- In this, copper tracks are provided on both sides of the substrate. To

achieve the connections between the boards, hole plating is done, which increase the

manufacturing complexity.

3) Multilayered PCB: - In this, two or more pieces of dielectric substrate material with circuitry

formed upon them are stacked up and bonded together. Electrically connections are

established from one side to the other and to the layer circuitry by drilled holes, which are

subsequently plated through copper.

4) Flexible PCB: - Flexible circuit is basically a highly flexible variant of the conventional rigid

printed circuit board theme.


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3.10.2 PCB Manufacturing Process: -

There are a number of different processes, which are used to manufacture a PCB, which

is ready for component assembly, from a copper clad base material. These processes are as follows:-

Preprocessing: - This consists of initial preparation of a copper clad laminate ready for

subsequent processing. Next is to drill tooling holes. Passing a board through rollers

performs cleaning operation.

Photolithography: - This process for PCBs involves the exposure of a photo resist material to

light through a mask. This is used for defining copper track and land patterns.

Etching: - The etching process is performed by exposing the surface of the board to an

etchant solution which dissolves away the exposed copper areas. The different solutions

used are: FeCl, CuCl, etc.

Drilling: - Drilling is used to create the component lead holes and through holes in a PCB

.The drilling can be done before or after the track areas have been defined.

Solder Masking: - It is the process of applying organic coatings selectively to those areas

where no solder wettings is needed .The solder mask is applied by screen-printing.

Metal Plating: - The plating is done to ensure protection of the copper tracks and establish

connection between different layers of multiplayer boards. PCBs are stacked before being

taken for final assembly of components. The PCB should retain its solder ability.

Bare-Board Testing: - Each board needs to ensure that the required connections exist, that

there are no short circuits and holes are properly placed. The testing usually consists of visual

inspection and continuity testing.

3.11RELAYS

A relay is usually an electromechanical device that is actuated by an electrical current.

The current flowing in one circuit causes the opening or closing of another circuit. Relays are like

remote control switches and are used in many applications because of their relative simplicity, long

life, and proven high reliability. They are used in a wide variety of applications throughout industry,

such as in telephone exchanges, digital computers and automation systems.

3.11.1How do relays work:

All relays contain a sensing unit, the electric coil, which is powered by AC or DC current.

When the applied current or voltage exceeds a threshold value, the coil activates the armature, which

operates either to close the open contacts or to open the closed contacts. When a power is supplied to


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the coil, it generates a magnetic force that actuates the switch mechanism. The magnetic force is, in

effect, relaying the action from one circuit to another.

The first circuit is called the control circuit; the second is called the load circuit. A relay

is usually an electromechanical device that is actuated by an electrical current.

3.11.2Types of Relays

There are two basic classifications of relays:

1. Electromechanical Relay

2. Solid State Relay.

Electromechanical relays have moving parts, whereas solid state relays have no movingparts. Advantages of Electromechanical relays include lower cost, no heat sink is required, multiple

poles are available, and they can switch AC or DC with equal ease.

3.11.2.1Electromechanical Relays :

General Purpose Relay: The general-purpose relay is rated by the amount of current its switchcontacts can handle. Most versions of the general-purpose relay have one to eight poles and can be

single or double throw. These are found in computers, copy machines, and other consumer electronic

equipment and appliances.


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FI Power Relay: The power relay is capable of handling larger power loads 10-50 amperes or

more. They are usually single-pole or double-pole units.

Contactor: A special type of high power relay, its used mainly to control high voltages and currents

in industrial electrical applications. Because of these high power requirements, contactors always

have double-make contacts.

Time-Delay Relay: The contacts might not open or close until sometime interval after the coil has

been energized. This is called delay-on-operate. Delay-on-release means that the contacts will

remain in their actuated position until some interval after the power has been removed from the coil.

A third delay is called interval timing. Contacts revert to their alternate position at a specific interval

of time after the coil has been energized.

The timing of these actions may be a fixed parameter of the relay, or adjusted by a knob on the relay

itself, or remotely adjusted through an external circuit.

3.11.2.2Solid State Relays

FIGURE 10


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These active semiconductor devices use light instead of magnetism to actuate a switch.

The light comes from an LED, or light emitting diode. When control power is applied to the devices

output, the light is turned on and shines across an open space.

On the load side of this space, a part of the device senses the presence of the light, and

triggers a solid state switch that either opens or closes the circuit under control.

Often, solid state relays are used where the circuit under control must be protected from

the introduction of electrical noises.

Advantages of Solid State Relays include low EMI/RFI, long life, no moving parts, no

contact bounce, and fast response.

The drawback to using a solid state relay is that it can only accomplish single pole

switching.

LM324 (LOW POWER QUAD OPERATIONAL AMPLIFIER)

GENERAL DESCRIPTION

The LM324 series consists of four independent, high gain, internally frequency

compensated operational amplifiers which were designed specifically to operate from a single power

supply over a wide range of voltages. Operation from split power supplies is also possible and the

low power supply current drain is independent of the magnitude of the power supply voltage.

Application areas include transducer amplifiers, DC gain blocks and all the conventional

op amp circuits which now can be more easily implemented in single power supply systems.


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For example, the LM324 series can be directly operated off of the standard a5V power

supply voltage which is used in digital systems and will easily provide the required interface

electronics without requiring the additional g15V power supplies.

UNIQUE CHARACTERISTICS

In the linear mode the input common-mode voltage range includes ground and the output

voltage can also swing to ground, even though operated from only a single power supply

voltage.

The unity gain cross frequency is temperature compensated.

The input bias current is also temperature compensated.

ADVANTAGES

Eliminates need for dual supplies

Four internally compensated op amps in a single package

Allows directly sensing near GND and VOUT also goes to GND

Compatible with all forms of logic

Power drain suitable for battery operation


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Fig. 2.18 CONNECTION DIAGRAM

FEATURES

Internally frequency compensated for unity gain

Large DC voltage gain 100 dB

Wide bandwidth (unity gain) 1 MHz (temperature compensated)

Wide power supply range: Single supply 3V to 32V or dual supplies g1.5V to g16V

Very low supply current drain (700 mA)Essentially independent of supply voltage

Low input biasing current 45 nA (temperature compensated)

Low input offset voltage 2 mV and offset current 5 nA

Input common-mode voltage range includes ground

Differential input voltage range equal to the power supply voltage

Large output voltage swing 0V to Va b 1.5V


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CHAPTER 4

ULN2003A (SEVEN DARLINGTON ARRAYS)

4.1Features

SEVEN DARLINGTONS PER PACKAGE

OUTPUT CURRENT 500ma PER DRIVER(600ma PEAK)

OUTPUT VOLTAGE 50V

INTEGRATED SUPPRESSION DIODES FORINDUCTIVE LOADS

OUTPUTS CAN BE PARALLELED FOR HIGHER CURRENT

TTL/CMOS/PMOS/DTL COMPATIBLE INPUTS

INPUTS PINNED OPPOSITE OUTPUTS TO SIMPLIFY LAYOUT

4.2DESCRIPTION

The ULN2003 is high voltage, high current darlington arrays each containing seven open collector

darlington pairs with common emitters.

Each channel rated at 500mA and can withstand peak currents of 600mA. Suppression

diodes are included for inductive load driving and the inputs are pinned opposite the outputs to

simplify board layout.

Fig. 2.19 IC ULN-2003 IN DIP-16 PACKAGE


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Fig. 2.20 PIN CONNECTION

The four versions interface to all common logic families:

ULN2001A General Purpose, DTL, TTL, PMOS, CMOS

ULN2002A 14-25V PMOS

ULN2003A 5V TTL, CMOS

ULN2004A 615V CMOS, PMOS

These versatile devices are useful for driving a wide range of loads including solenoids, relays DC

motors, LED displays filament lamps, thermal printheads and high power buffers.

CHAPTER 5


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APPLICATION AND ADVANTAGES

5.1 APPLICATION

1. Automotive and transport vehicles.

2. With advance technology, it can be use in broad areas of transportation.

5.2 ADVANTAGES

1. Sophisticated security.

2. Monitor all hazards and threats.

3. Mobile number can be changed with changing some settings.

4. Alert the driver about any threat by giving alarm.


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BIBLEOGRAPHY

www.wikepedia.com

www.kpsec.freeuk.com

The 8051 microcontroller by Ayala

The microcontroller idea book by Jan Axelson

8051 tutorial from www.8052.com

8051 micro-controller architecture, introduction to assembly programming by Parl vallal kannan

(centre for integrated circuits and systems University of Texas at Dallas).

www.digichip.com

www.datasheets4u.com

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