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DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
HIGHWAY ALERT SIGNAL LAMP
A Mini-Project report submitted in partial fulfillment of the requirements for the
award of the degree
BACHELOR OF TECHNOLOGY
IN
ELECTRONICS AND INSTRUMENTATION ENGINEERING
Submitted by
K.VENKATA AKHIL
(13761A1006)
Under the Esteemed Guidance of
R.ANJANEYULU NAIK
(Assoc. Professor)
DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION ENGINEERING
LAKIREDDY BALIREDDY COLLEGE OF ENGINEERING (AUTONOMOUS)
(Approved by AICTE, Affiliated to JNTU, Accredited by NAAC and ISO 9001-2008 certified)
MYLAVARAM, KRISHNA DIST-521230, ANDHRA PRADESH
2014-2015
LAKIREDDY BALIREDDY COLLEGE OF ENGINEERING
DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION ENGINEERING
LAKIREDDY BALIREDDY COLLEGE OF ENGINEERING (AUTONOMOUS)
(Approved by AICTE, Affiliated to JNTUK, Accredited by NAAC and ISO 9001-2008 Certified)
MYLAVARAM, KRISHNA (DIST)-521230, ANDHRA PRADESH
This is to certificate that the mini-project entitled “HIGHWAY ALERT SIGNAL
LAMP” is a bonafide work done by K.VENKATA AKHIL (13761A1006) during the academic
year 2013-14 in partial fulfillment of the requirements of II-B.TECH (SEM-IV) for the award of
the degree BACHELOR OF TECHNOLOGY by JNTU, Kakinada. This work is not submitted to
any university or institution for the award of any degree or diploma.
PROJECT GUIDE
R.ANJANEYULU NAIK
(Assoc. Professor)
PROJECT COORDINATOR
Mrs.V.Vineela
HEAD OF DEPARTMENT
Dr. K.SRINIVASA RAO
PROFESSOR
Viva-Voce:
(Mini project in-charge)
(External Examiner)
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ACKNOWLEDGMENT
Behind every achievement lies an unfathomable sea of gratitude to those who activated it,
without whom it would ever have been in existence. To whom we lay the words of gratitude to
Dr.E.V. Prasad, Director of LBRCE, who has been the driving force behind LBRCE and who
made this endeavor possible.
We would
like to
thank
R.ANJANEYULU NAIK Assoc Professor, Department of EIE
who has been an inspiring guide and committed faculty and gave moral support in every stage of
our mini-project. The encouragement and support extended by him motivated us to complete this
project.
We also take the privilege to record our thanks to Dr.K.Srinivasa Rao Ph.D Professor&HOD ,
Department of EIE, whose encouragement, cooperation and valuable support led to the
successful completion of our mini-project. Our sincere thanks to the Librarian of LBRCE who
helped us in collecting the necessary literature related to our mini-project. We are thankful to all
the teaching and non-teaching staff of EIE Department for their direct as well as indirect help in
our project. We also avail ourselves of this opportunity to express our deep sense of gratitude to
our parents.
K.VENKATA AKHIL
13761A1006
LAKIREDDY BALIREDDY COLLEGE OF ENGINEERING
DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
INDEX
CONTENTS
PAGE NO:
 ABSTRACT
1
 INTRODUCTION
2
 COMPONENTS REQURIED
3
 DESCRIPTION OF COMPONENTS
1. PHOTOTRANSISTOR
2.IC555
4-5
3.TRANSISTOR
4.RESISTOR
5.CAPACITOR
6. LEDs
7. BATTERY
8. BREAD BOARD
6-10
11
12-15
16-17
18-19
20
21-23
CIRCUIT DIAGRAM
24
 WORKING PRICIPLE
25
 APPLICATION & ADVANTAGES
26
 COUNCLUSION
27
 REFERENCE
28

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ABSTRACT
Here is a signal lamp for safe highway driving. The lamp automatically emits brilliant tricolour
light when a vehicle approaches the rear side of your vehicle. It emits light for 30 seconds that
turns off when the approaching vehicle overtakes. The ultra-bright blue, white and red LEDs of
the signal lamp emit very bright light to alert the approaching vehicle’s driver even during the
day, giving additional safety during night, or when you need to stop your vehicle on side of the
highway. The circuit saves considerable battery power.
The circuit is built around two timer ICs NE555 (IC1 and IC2). IC1 is designed as a standard
monostable, while IC2 is designed as an astable. Darlington phototransistor L14F1 (T1) is used
as a photo sensor to activate the monostable. The collector of phototransistor T1 is connected to
trigger pin 2 of IC1, which is normally kept high by resistor R1.
When headlight from an approaching vehicle illuminates the phototransistor, it conducts to give
a short pulse to IC1, and the output of IC1 goes high for a period determined by resistor R2 and
capacitor C1. The output of IC1 is fed to the base of transistor T2 via resistor R3. Transistor T2
conducts to drive transistor T3 and its collector goes high to take reset pin 4 of IC2 to high level.
This activates astable IC2, which switches on and off the LED chain alternately. The intermittent
flashing of LEDs gives a beautiful tricolor flashlight effect.
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INTRODUCTION
The lighting system of a motor vehicle consists of lighting and signalling devices mounted or
integrated to the front, sides, rear, and in some cases the top of the vehicle. The purpose of this
system is to provide illumination for the driver to operate the vehicle safely after dark, to
increase the conspicuity of the vehicle, and to display information about the vehicle's presence,
position, size, direction of travel, and driver's intentions regarding direction and speed of travel.
Driving lamp" is a term deriving from the early days of night time driving, when it was relatively
rare to encounter an opposing vehicle. Only on those occasions when opposing drivers passed
each other would the dipped or "passing" beam be used. The full beam was therefore known as
the driving beam. Turn signals are required to blink on and off, or "flash", at a steady rate of
between 60 and 120 blinks per minute (Although some operate slower than this). International
regulations require that all turn signals activated at the same time (i.e., all right signals or all left
signals) flash in simultaneous phase with one another; North American regulations also require
simultaneous operation, but permit side markers wired for side turn signal functionality to flash
in opposite-phase. Worldwide regulations stipulate an audiovisual telltale when the turn signals
are activated; this usually takes the form of one combined or separate left and right green
indicator lights on the vehicle's instrument cluster, and a cyclical "tick-tock" noise generated
electromechanically or electronically. It is also required that audio and/or visual warning be
provided to the vehicle operator in the event of a turn signal's failure to light. This warning is
usually provided by a much faster- or slower-than-normal flash rate, visible on the dashboard
indicator, and audible via the faster tick-tock sound.
Turn signals are in almost every case activated by means of a horizontal lever (or "stalk")
protruding from the side of the steering column, though some vehicles have the lever mounted
instead to the dashboard. The outboard end of the stalk is pushed clockwise to activate the right
turn signals, or anticlockwise for the left turn signals. This operation is intuitive; for any given
steering manoeuvre, the stalk is pivoted in the same direction as the ateering wheel must be
turned.
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2. COMPONENTS USED
Resistors
R1 = 8.2k
R2 = 4.7k
R3 = 10k
R4 = 100
R5 = 470
R6 = 22k
R7 = 33k
IC 555
Capacitor
Darlington Phototransistor (L14F1)
Transistor
LEDs
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3. DESCRIPTION OF COMPONENTS
1.Phototransistor:
•
A transistor that uses light rather than electricity to cause an electrical current to flowfro
m one side to the other. It is used in a variety of sensors that detect the presence of light.
Phototransistors combine aphotodiode and transistor together to generate more output cur
rent than a photodiode by itself.
•
A phototransistor consists of a singlecrystal Ge or Si semiconductor wafer in which three
regions are produced bymeans of special technological processes. As in a conventional tr
ansistor, the regions are called the emitter, collector,and base; as a rule, the base has no le
ad.
•
Photo transistors are operated in their active regime, although the base connection is left
open circuit or disconnected because it is not required. The base of the photo transistor
would only be used to bias the transistor so that additional collector current was flowing
and this would mask any current flowing as a result of the photo-action. For operation the
bias conditions are quite simple. The collector of an n-p-n transistor is made positive with
respect to the emitter or negative for a p-n-p transistor.
•
The light enters the base region of the phototransistor where it causes hole electron pairs
to be generated. This mainly occurs in the reverse biased base-collector junction. The
hole-electron pairs move under the influence of the electric field and provide the base
current, causing electrons to be injected into the emitter.
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Fig.12: Darling-ton Phototransistor
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2.555 IC:
The 555 timer IC was first introduced around 1971 by the Signet Corporation as the
SE555/NE555 and was called "The IC Time Machine" and was also the very first and only
commercial timer IC available. It provided circuit designers with a relatively cheap, stable, and
user-friendly integrated circuit for both mono stable applications. Since this device was first
made commercially available, a myriad of novel and unique circuits have been developed and
presented in several trade, professional, and hobby publications. The past ten years some
manufacturers stopped making these timers because of competition or other reasons. Yet other
companies, like NTE (a subdivision of Philips) picked up where some left off.
Although these days the CMOS version of this IC, like the MC1455, is mostly used, the
regular type is still available however there have been many improvements and variations in the
circuitry.
But
all
types
are
pin-for-pin
plug
compatible.
In this tutorial the 555 timer is examined in detail along with its uses, either by itself or in
combination with other solid state devices. This timer uses a maze of transistors, diodes and
resistors and for this complex reason a more simplified (but accurate) block diagram is used to
explain the internal organizations of the 555.
The ic555 contains 8 pins. The explanation about these 8 pins is
Pin 1(GROUND): The ground (or common) pin is the most-negative supply potential of the
device,
which
is
normally
connected
to
circuit
common
(ground)
whenoperatedfrompositivesupplyvoltages.
Pin 2(TRIGGER): This pin is the input to the lower comparator and is used to set the latch,
which in turn causes the output to go high. This is the beginning of the timing sequence in mono
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stable operation. Triggering is accomplished by taking the pin from above to below a voltage
level of 1/3 V+ (or, in general, one-half the voltage appearing at pin 5). The action of the trigger
input is level-sensitive, allowing slow rate-of-change waveforms, as well as pulses, to be used as
trigger sources. The trigger pulse must be of shorter duration than the time interval determined
by the external R and C. If this pin is held low longer than that, the output will remain high until
the trigger input is driven high again.
Pin 3(OUT PUT): The output of the 555 comes from a high-current totem-pole stage made up
of transistors Q20 - Q24. Transistors Q21 and Q22 provide drive for source-type loads, and their
Darlington connection provides a high-state output voltage about 1.7 volts less than the V+
supply level used. Transistor Q24 provides current-sinking capability for low-state loads referred
to V+ (such as typical TTL inputs). Transistor Q24 has a low saturation voltage, which allows it
to interface directly, with good noise margin, when driving current-sinking logic. Exact output
saturation levels vary markedly with supply voltage, however, for both high and low states
Pin 4(RESET): This pin is also used to reset the latch and return the output to a low state. The
reset voltage threshold level is 0.7 volt, and a sink current of 0.1mA from this pin is required to
reset the device. These levels are relatively independent of operating V+ level; thus the reset
input
is
TTL
compatible
for
any
supply
voltage.
The reset input is an overriding function; that is, it will force the output to a low state regardless
of the state of either of the other inputs.
Pin 5(CONTROL VOLTAGE): This pin allows direct access to the 2/3 V+ voltage-divider
point, the reference level for the upper comparator. It also allows indirect access to the lower
comparator, as there is a 2:1 divider (R8 - R9) from this point to the lower-comparator reference
input, Q13. Use of this terminal is the option of the user, but it does allow extreme flexibility by
permitting modification of the timing period, resetting of the comparator, etc.
When the 555 timer is used in a voltage-controlled mode, its voltage-controlled operation ranges
from about 1 volt less than V+ down to within 2 volts of ground (although this is not
guaranteed).
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.
Fig. 2: IC555
Monostable mode
Monostable multivibrator often called a one shot multivibrator is a pulse generating
circuit in which the duration of this pulse is determined by the RC network connected
externally to the 555 timer. In a stable or standby state, the output of the circuit is
approximately zero or a logic-low level. When external trigger pulse is applied output
is forced to go high (» VCC). The time for which output remains high is determined by
the external RC network connected to the timer. At the end of the timing interval, the
output automatically reverts back to its logic-low stable state. The output stays low
until trigger pulse is again applied. Then the cycle repeats. The monostable circuit has
only one stable state (output low) hence the name monostable.
Fig.3: Circuit Diagram of Monostable Multivibrator
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Waveform
Fig.4: Output Waveform of IC555 in Monostable Mode
Astable mode
The astable multivibrator generates a square wave, the period of which is determined
by the circuit external to IC 555. The astable multivibrator does not require any
external trigger to change the state of the output. Hence the name free running
oscillator. The time during which the output is either high or low is determined by the
two resistors and a capacitor which are externally connected to the 555 timer. The
figure shows the 555 timer connected as an astable multivibrator. Initially when the
output is high capacitor C starts charging towards Vcc through RA and RB.
Fig.5: Circuit Diagram of 555 timer in Astable Mode
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Waveform
Fig.6: Output waveform of 555 timer in Astable Mode
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3.Transistor:
A transistor is a semiconductor device used to amplify and switch electronic signals. It is made
of a solid piece of semiconductor material, with at least three terminals for connection to an
external circuit. A voltage or current applied to one pair of the transistor's terminals changes the
current flowing through another pair of terminals. Because the controlled (output) power can be
much more than the controlling (input) power, the transistor provides amplification of a signal.
Some transistors are packaged individually but many more are found embedded in integrated
circuits.The transistor is the fundamental building block of modern electronic devices, and its
presence is ubiquitous in modern electronic systems.
Fig.7: Transistor
•
The BC548 is a general purpose epitaxial silicon NPN bipolar junction transistor found
commonly in European electronic equipment. that included the high-voltage BC107
and low noise BC109 variants.
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4.RESISTOR:
A resistor is a passive two-terminal electrical component that implements electrical resistance as
a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage
levels within circuits. Resistors may have fixed resistances or variable resistances, such as those
found in thermistors, varistors, trimmers, photoresistors, humistors, piezoresistors and
potentiometers.
The current through a resistor is in direct proportion to the voltage across the resistor's terminals.
This relationship is represented by Ohm's law:
I=V/R
where I is the current through the conductor in units of amperes, V is the potential difference
measured across the conductor in units of volts, and R is the resistance of the conductor in units
of ohms (symbol: Ω).
The ratio of the voltage applied across a resistor's terminals to the intensity of current in the
circuit is called its resistance, and this can be assumed to be a constant (independent of the
voltage) for ordinary resistors working within their ratings.
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous
in electronic equipment. Practical resistors can be composed of various compounds and films, as
well as resistance wires (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors
are also implemented within integrated circuits, particularly analog devices, and can also be
integrated into hybrid and printed circuits.
The electrical functionality of a resistor is specified by its resistance: common commercial
resistors are manufactured over a range of more than nine orders of magnitude. When specifying
that resistance in an electronic design, the required precision of the resistance may require
attention to the manufacturing tolerance of the chosen resistor, according to its specific
application. The temperature coefficient of the resistance may also be of concern in some
precision applications. Practical resistors are also specified as having a maximum power rating
which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is
mainly of concern in power electronics applications. Resistors with higher power ratings are
physically larger and may require heat sinks. In a high-voltage circuit, attention must sometimes
be paid to the rated maximum working voltage of the resistor. While there is no minimum
working voltage for a given resistor, failure to account for a resistor's maximum rating may
cause the resistor to incinerate when current is run through it.
Practical resistors have a series inductance and a small parallel capacitance; these specifications
can be important in high-frequency applications. In a low-noise amplifier or pre-amp, the noise
characteristics of a resistor may be an issue. The unwanted inductance, excess noise, and
temperature coefficient are mainly dependent on the technology used in manufacturing the
resistor. They are not normally specified individually for a particular family of resistors
manufactured using a particular technology.[1] A family of discrete resistors is also
characterized according to its form factor, that is, the size of the device and the position of its
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leads (or terminals) which is relevant in the practical manufacturing of circuits using them.
Resistor values - the resistor colour code
Resistance is measured in ohms, the symbol for ohm is an omega ohm.
1 ohm is quite small so resistor values are often given in kohm and Mohm.
1 kohm = 1000 ohm 1 Mohm = 1000000 ohm.
Resistor values are normally shown using coloured bands.
Each colour represents a number as shown in the table.
Most resistors have 4 bands:
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The first band gives the first digit.
The second band gives the second digit.
The third band indicates the number of zeros.
The fourth band is used to shows the tolerance (precision) of the resistor, this may be ignored for
almost all circuits
This resistor has red (2), violet (7), yellow (4 zeros) and gold bands.
So its value is 270000 ohm = 270 kohm.
On circuit diagrams the ohm is usually omitted and the value is written 270K.
Find out how to make your own Colour Code Calculator.
Small value resistors (less than 10 ohm)
The standard colour code cannot show values of less than 10ohm. To show these small values
two special colours are used for the third band: gold which means × 0.1 and silver which means
× 0.01. The first and second bands represent the digits as normal.
For example:
red, violet, gold bands represent 27 × 0.1 = 2.7 ohm
green, blue, silver bands represent 56 × 0.01 = 0.56 ohm
Tolerance of resistors (fourth band of colour code)
The tolerance of a resistor is shown by the fourth band of the colour code. Tolerance is the
precision of the resistor and it is given as a percentage. For example a 390ohm resistor with a
tolerance of ±10% will have a value within 10% of 390ohm, between 390 - 39 = 351ohm and
390 + 39 = 429ohm (39 is 10% of 390).
A special colour code is used for the fourth band tolerance:
silver ±10%, gold ±5%, red ±2%, brown ±1%.
If no fourth band is shown the tolerance is ±20%.
Tolerance may be ignored for almost all circuits because precise resistor values are rarely
required.
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Fig.8: Resistor
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5.CAPACITOR:
A capacitor (originally known as a condenser) is a passive two-terminal electrical component
used to store energy electrostatically in an electric field. The forms of practical capacitors vary
widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e.,
insulator). The conductors can be thin films of metal, aluminum foil or disks, etc. The
'nonconducting' dielectric acts to increase the capacitor's charge capacity. A dielectric can be
glass, ceramic, plastic film, air, paper, mica, etc. Capacitors are widely used as parts of electrical
circuits in many common electrical devices. Unlike a resistor, a capacitor does not dissipate
energy. Instead, a capacitor stores energy in the form of an electrostatic field between its plates.
When there is a potential difference across the conductors (e.g., when a capacitor is attached
across a battery), an electric field develops across the dielectric, causing positive charge (+Q) to
collect on one plate and negative charge (-Q) to collect on the other plate. If a battery has been
attached to a capacitor for a sufficient amount of time, no current can flow through the capacitor.
However, if an accelerating or alternating voltage is applied across the leads of the capacitor, a
displacement current can flow.
An ideal capacitor is characterized by a single constant value for its capacitance. Capacitance is
expressed as the ratio of the electric charge (Q) on each conductor to the potential difference (V)
between them. The SI unit of capacitance is the farad (F), which is equal to one coulomb per volt
(1 C/V). Typical capacitance values range from about 1 pF (10−12 F) to about 1 mF (10−3 F).
The capacitance is greater when there is a narrower separation between conductors and when the
conductors have a larger surface area. In practice, the dielectric between the plates passes a small
amount of leakage current and also has an electric field strength limit, known as the breakdown
voltage. The conductors and leads introduce an undesired inductance and resistance.
Capacitors are widely used in electronic circuits for blocking direct current while allowing
alternating current to pass. In analog filter networks, they smooth the output of power supplies.
In resonant circuits they tune radios to particular frequencies. In electric power transmission
systems they stabilize voltage and power flow.
A capacitor consists of two conductors separated by a non-conductive region.[10] The nonconductive region is called the dielectric. In simpler terms, the dielectric is just an electrical
insulator. Examples of dielectric media are glass, air, paper, vacuum, and even a semiconductor
depletion region chemically identical to the conductors. A capacitor is assumed to be selfcontained and isolated, with no net electric charge and no influence from any external electric
field. The conductors thus hold equal and opposite charges on their facing surfaces,[11] and the
dielectric develops an electric field. In SI units, a capacitance of one farad means that one
coulomb of charge on each conductor causes a voltage of one volt across the device.[12]
An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of
charge ±Q on each conductor to the voltage V between them
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Capacitors are two-terminal electrical elements. Capacitors are essentially two conductors,
usually conduction plates - but any two conductors - separated by an insulator - a dielectric with conection wires connected to the two conducting plates.
Capacitors occur naturally. On printed circuit boards two wires running parallel to each
other on opposite sides of the board form a capacitor. That's a capacitor that comes about
inadvertently, and we would normally prefer that it not be there. But, it's there. It has electrical
effects, and it will affect your circuit. You need to understand what it does.
At other times, you specifically want to use capacitors because of their frequency dependent
behavior. There are lots of situations where we want to design for some specific frequency
dependent behavior. Maybe you want to filter out some high frequency noise from a lower
frequency signal. Maybe you want to filter out power supply frequencies in a signal running near
a 60 Hz line. You're almost certainly going to use a circuit with a capacitor.
Sometimes you can use a capacitor to store energy. In a subway car, an insulator at a track
switch may cut off power from the car for a few feet along the line. You might use a large
capacitor to store energy to drive the subway car through the insulator in the power feed.
Capacitors are used for all these purposes, and more. In this chapter you're going to start
learning about this important electrical component. Remember capacitors do the following and
more.
Store energy
Change their behavior with frequency
Come about naturally in circuits and can change a circuit's behavior
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fig.9:Capacitor
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6.LEDs:
This publication answers some commonly asked questions about lighting systems using light
emitting diodes (LEDs). Lighting Answers: LED Lighting Systems helps practitioners
understand the differences between LEDs and other conventional light sources, as well as some
of their relevant performance characteristics. Key issues that are important in understanding the
effective use of LEDs in lighting applications, including electrical performance, thermal
performance, and optical performance are described. This publication should be useful to any
practitioner who wants to use LED systems effectively in lighting applications.
Introduction
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Light emitting diodes (LEDs) were first developed in the 1960s, but only in the past decade have
LEDs had sufficient intensity for use in more than a handful of lighting applications
(Stringfellow and Craford 1997), and specifiers are confronted with an increasing number of
lighting products that incorporate LEDs for certain applications. Primarily, these applications
have taken advantage of the characteristics of LEDs that have made them most suitable for
indication, not illumination
LEDs are semiconductor diodes, electronic devices that permit current to flow in only one
direction. The diode is formed by bringing two slightly different materials together to form a PN
junction. In a PN junction, the P side contains excess positive charge ("holes," indicating the
absence of electrons) while the N side contains excess negative charge (electrons).The material
used in the semiconducting element of an LED determines its color. The two main types of
LEDs presently used for lighting systems are aluminum gallium indium phosphide (AlGaInP,
sometimes rearranged as AlInGaP) alloys for red, orange and yellow LEDs; and indium gallium
nitride (InGaN) alloys for green, blue and white LEDs. Slight changes in the composition of of
these alloys changes the color of the emitted light.
Table 1. Relative advantages and disadvantages of methods for creating white light with LEDs.
Mixed-color white LEDs
Phosphor-converted white LEDs
Advantages
higher overall luminous efficacy
good color rendering properties
complete flexibility for achieving any desired color property
18
Advantages
results in a single, compact, white light source
Disadvantages
difficult to completely mix light
difficult to maintain color stability over life and at different operating conditions, including
dimming
Disadvantages
lower overall luminous efficacy
uniform application of phosphor in manufacturing process is more difficult to control
limited range of available color properties based on phosphor availability
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.
Fig.10: LEDs
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7.Battery:
The battery cells create a voltage difference between the terminals of each cell and
hence to its combination in battery.
When an external circuit is connected to the battery, then the battery drives electrons
through the circuit and electrical work is done. The battery has become a common
power source for many household and industrial applications, and is now a multibillion dollar industry.
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Fig.11: Battery
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8.BREAD BOARD:
A breadboard (or protoboard) is usually a construction base for prototyping of electronics. The
term "breadboard" is commonly used to refer to a solderless breadboard (plugboard).
A breadboard originally was a flat wooden cutting board used to support a loaf of bread (or other
foods) while it was being sliced; this original meaning is still in use, but has a new additional
meaning as "a base for prototyping". The concept of "breadboarding" as prototyping is not
confined to electronic design; "mechanical breadboards" have been and continue to be used by
mechanical engineers.
Because the solderless breadboard for electronics does not require soldering, it is reusable. This
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makes it easy to use for creating temporary prototypes and experimenting with circuit design.
Older breadboard types did not have this property. A stripboard (veroboard) and similar
prototyping printed circuit boards, which are used to build semi-permanent soldered prototypes
or one-offs, cannot easily be reused. A variety of electronic systems may be prototyped by using
breadboards, from small analog and digital circuits to complete central processing units (CPUs).
Uses of Breadboard:
A breadboard is used to make up temporary circuits for testing or to try out an idea. No soldering
is required so it is easy to change connections and replace components. Parts will not be
damaged so they will be available to re-use afterwards.
Almost all the Electronics Club projects started life on a breadboard to check that the circuit
worked as intended.
The photograph shows a typical small breadboard which is suitable for beginners building simple
circuits with one or two ICs (chips). Larger sizes are available and you may wish to buy one of
these to start with.
Connections on Breadboard:
Breadboards have many tiny sockets (called 'holes') arranged on a 0.1" grid. The leads of most
components can be pushed straight into the holes. ICs are inserted across the central gap with
their notch or dot to the left.
Wire links can be made with single-core plastic-coated wire of 0.6mm diameter (the standard
size). Stranded wire is not suitable because it will crumple when pushed into a hole and it may
damage the board if strands break off.
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DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
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DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
Building a Circuit on Breadboard:
Converting a circuit diagram to a breadboard layout is not straightforward because the
arrangement of components on breadboard will look quite different from the circuit diagram.
When putting parts on breadboard you must concentrate on their connections, not their positions
on the circuit diagram. The IC (chip) is a good starting point so place it in the centre of the
breadboard and work round it pin by pin, putting in all the connections and components for each
pin in turn.
Bread Board is a great tool to design and test your circuits. You do not need to solder wires and
components to make a circuit while using a bread board. It is easier to mount components &
reuse them. Since, components are not soldered you can change your circuit design at any point
without any hassle.
Structure of a Bread Board: Basically, a bread board is an array of conductive metal clips
encased in a box made of white ABS plastic, where each clip is insulated with another clips.
There are a number of holes on the plastic box, arranged in a particular fashion. A typical bread
board layout consists of two types of region also called strips. Bus strips and socket strips. Bus
strips are usually used to provide power supply to the circuit. It consists of two columns, one for
power voltage and other for ground.
Socket strips are used to hold most of the components in a circuit. Generally it consists of two
sections each with 5 rows and 64 columns. Every column is electrically connected from inside.
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DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
4. CIRCUIT DIAGRAM
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5. WORKING PRINCIPLE
This is the signal lamp for safe highway driving. The lamp automatically emits brilliant tricolour
light when a vehicle approaches the rear side of your vehicle. It emits light for 30 seconds that
turns off when the approaching vehicle overtakes. The ultra-bright blue, white and red LEDs of
the signal lamp emit very bright light to alert the approaching vehicle’s driver even during the
day, giving additional safety during night or when you need to stop your vehicle on side of the
highway. The circuit saves considerable battery power.
The circuit is built around two timer ICs NE555(IC1& IC2). IC1 is designed as a standard
monostable, while IC2 is designed as an astable. Darlington Phototransistor L14F1 (T1) is used
as a photosensor to activate the monostable. The collector of Phototransistor T1 is connected to
trigger pin 2 of IC1, which is normally kept high by resistor R1. When headlight from an
approaching vehicle illuminates the phototransistor, it conducts to give a short pulse to IC1, and
the output of IC1 goes high for a 4 period determined by resistor R2 and capacitor C1. The
output of IC1 is fed to the base of transistor T2 via resistor R3. Transistor T2 conducts to drive
transistor T3 and its collector goes high to take reset pin 4 of IC2to high level. This activates
astable IC2, which switches on and off the LED chain alternately. The intermittent flashing of
LEDs gives a beautiful tricolour flashing effect. 12 volt DC supply to the circuit, can be provided
by your vehicle battery with proper polarity.
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APPLICATION & ADVANTAGES
•
This is used in the cars, buses and many other vehicles to alert them at the roads on night
and morning when a car is overtaking our car
•
We use tricolors so they produce high intensity lights and alerts the drivers
•
By using we can avoid the accidents at night
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6. CONCLUSION
In this project I have learned a lot about the SIGNAL LAMP scenario in the field of
communication. This circuit is used for safe highway driving. This circuit inform the driver
about the approaching vehicle. It also help the driver if the driver wants to stop for sometime on
highway. It saves battery power.
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DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION
REFERENCE
https://www.google.co.in/#q=electronics+for+you
http://www.authorstream.com/Presentation/ddwmumbai-1922892highway-alert-signal-lamp/
https://www.google.co.in/#q=highway+alert+signal+lamp+project+repo
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