PREFACE

Engineering is not only a theoretical study but it is an implementation of all .We study for
creating something new and making things more easy and useful through practical study.
It is an art which can be gained with systematic study, observation and practice. In the
college curriculum we usually get the theoretical knowledge of industries and a little bit
of implementation knowledge that how it works? But how we prove our practical
knowledge to increase the productivity or efficiency of industries? To overcome such
problem we student of college name……………………………………………………are
supposed to make project on “AUTOMATIC STREET LIGHT”. This project is
designed to automatically glow the street lights or switch it off according to the natural
lighting conditions. Street lights with manual switching remains ON during daytime till
someone see it and switch it off. This results in the unnecessary wastage of the electricity.
The circuit designed by us saves the extra electricity consumed in daytime.

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 TABLE OF CONTENTS
CHAPTER NO. TITLE PAGE NO.

CHAPTER-1 INTRODUCTION 4

CHAPTER-2 PRINCIPLE AND WORKING 5

CHAPTER-3 CIRCUIT DIAGRAM 7

CHAPTER-4 COMPONENTS LIST 9

CHAPTER-5 COMPONENT DESCRIPTION 10

CHAPTER-6. PCB LAYOUT 32

CHAPTER-7. SOLDERING AND DISORDERING 33

CHAPTER-8 APPLICATIONS 38

ADVANTAGES AND
CHAPTER-9 39
DISADVANTAGES

CHAPTER-10 CONCLUSION 40

REFERENCES 41

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 LIST OF FIGURES
FIG. No. FIGURES PAGE NO
FIG 3.1 CIRCUIT DIAGRAM OF AUTOMATIC STREET LIGHT 7
FIG 3.2 BLOCK DIAGRAM OF AUTOMATIC STREET LIGHT 8
FIG 5.1 LDR 10
FIG 5.2 SYMBOLIC REPRESENTATION OF LDR 11
FIG 5.3 NE555 TIMER IC 12
FIG 5.4 PIN DIAGRAM OF NE555 TIMER IC 12
FIG 5.5 INTERNAL STRUCTURE OF LED 13
FIG 5.6 RESISTOR 14
FIG 5.7 ON/OFF SWITCHES 17
FIG 5.8 BATTERY 26
FIG 6.1 PCB FRONT VIEW 27
FIG 6.2 PCB BACK VIEW 27
FIG 6.3 LAYOUT OF STREET LIGHT CIRCUIT MODEL 27
FIG 7.1 SOLDERING PROCEDURE 28
FIG 7.2 DESOLDERING PROCEDURE 30
FIG 7.2 PHOTOGRAPH OF AUTOMATIC STREET LIGHT 32

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 CHAPTER-1

INTRODUCTION

Introduction

This circuit of automated street light needs no manual operation for switching ON

and OFF. When there is a need of light in the street it automatically switches ON.

When darkness rises to a certain level then sensor circuit gets activated and

switches ON and when there is other source of light i.e. daytime, the street light

gets OFF. The sensitiveness of the street light can also be adjusted. In our project

we have used four

L.E.D as a symbol of street lamp, but for high power switching one can connect

Relay (electromagnetic switch) at the output of pin 3 of I.C 555 that will make

easy to turn ON/OFF any electrical appliances that are connected through relay

and we can use a bulb instead of the LEDs for the illuminating the streetlight.

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 CHAPTER-2
PRINCIPLE AND WORKING
Principle:-

This circuit uses a popular timer I.C 555. I.C 555 is connected as comparator with
pin-6 connected with positive rail, the output goes high(1) when the trigger pin 2
is at lower then 1/3rd level of the supply voltage. Conversely the output goes low
(0) when it is above 1/3rd level. So small change in the voltage of pin-2 is enough
to change the level of output (pin-3) from 1 to 0 and 0 to 1. The output has only
two states high and low and cannot remain in any intermediate stage. It is powered
by a 6V battery for portable use. The circuit is economic in power consumption.
Pin 4, 6 and 8 is connected to the positive supply and pin 1 is grounded. To detect
the present of an object we have used LDR and a source of light.

LDR is a special type of resistance whose value depends on the brightness of the
light which is falling on it. It has resistance of about 1 mega ohm when in total
darkness, but a resistance of only about 5k ohms when brightness illuminated. It
responds to a large part of light spectrum. We have made a potential divider circuit
with LDR and 100K variable resistance connected in series. We know that voltage
is directly proportional to conductance so more voltage we will get from this
divider when LDR is getting light and low voltage in darkness. This divided
voltage is given to pin 2 of IC 555. Variable resistance is so adjusted that it crosses
potential of 1/3rd in brightness and fall below 1/3rd in
darkness. Sensitiveness can be adjusted by this variable resistance. As soon as
LDR gets dark the voltage of pin 2 drops 1/3rd of the supply voltage and pin 3
gets high and LED or buzzer which is connected to the output gets activated.

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 WORKING:-

When light falls on the LDR then its resistance decreases which results in
increase of the voltage at pin 2 of the IC 555. IC 555 has got comparator
inbuilt, which compares between the input voltage from pin2 and 1/3rd of the
power supply voltage. When input falls below 1/3rd then output is set high
otherwise it is set low. Since in brightness, input voltage rises so we obtain no
positive voltage at output of pin 3 to drive relay or LED, besides in poor light
condition we get output to energize.

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 CHAPTER-3
CIRCUIT DIAGRAM:-

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 BLOCK DIAGRAM:-

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 CHAPTER-4
COMPONENTS

COMPONENTS LIST:-

 L.D.R (Light Dependent Resistor)

 I.C NE555 with Base
 L.E.D (Light Emitting Diode) 3 to 6 pieces.
 Variable resistance
 On/off switch
 12 volt supply
 47k trimmer or preset
 330e resistor
 12 volt relley
 4007 diod
 7805 ic

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 CHAPTER-5
COMPONENT DESCRIPTION WITH SPECIFICATIONS

LDR (LIGHT DEPENDENT RESISTOR/PHOTO-

RESISTOR):-

A photoelectric device can be either intrinsic or extrinsic. An intrinsic

semiconductor has its own charge carriers and is not an efficient
semiconductor, for example, silicon. In intrinsic devices the only available
electrons are in the valence band, and hence the photon must have enough
energy to excite the electron across the entire band gap. Extrinsic devices have
impurities, also called dopants, and added whose ground state energy is closer
to the conduction band; since the electrons do not have as far to jump, lower
energy photons (that is, longer wavelengths and lower frequencies) are
sufficient to trigger the device. If a sample of silicon has some of its atoms
replaced by phosphorus atoms (impurities), there will be extra electrons
available for conduction. This is an example of an extrinsic semiconductor.

An LDR

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Photo-resistors are less light-sensitive devices than photodiodes or
phototransistors: the two latter components are true semiconductor devices,
while a photo-resistor is a passive component and does not have a PN-junction.
The photo resistivity of any photo-resistor may vary widely depending on
ambient temperature, making them unsuitable for applications requiring precise
measurement of or sensitivity to light.

Photo-resistors also exhibit a certain degree of latency between exposure to

light and the subsequent decrease in resistance, usually around 10 milliseconds.
The lag time when going from lit to dark environments is even greater, often as
long as one second. This property makes them unsuitable for sensing rapidly
flashing lights, but is sometimes used to smooth the response of audio signal
compression.

Symbolic Representation of LDR

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I.C. NE 555
The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse
generation, and oscillator applications. The 555 can be used to provide time
delays, as an oscillator, and as a flip-flop element. Derivatives provide up to
four timing circuits in one package.

Depending on the manufacturer, the standard 555 package includes 25

transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin
mini dual-in-line package (DIP-8).Variants available include the 556 (a 14-pin
DIP combining two 555s on one chip), and the two 558 & 559s (both a 16-pin
DIP combining four slightly modified 555s with DIS & THR connected
internally, and TR is falling edge sensitive instead of level sensitive).

The NE555 parts were commercial temperature range, 0°C to +70°C, and
the SE555 part number designated the military temperature range, −55°C to
+125°C. These were available in both high-reliability metal can (T package)
and inexpensive epoxy plastic (V package) packages. Thus the full part
numbers were NE555V, NE555T, SE555V, and SE555T. It has been
hypothesized that the 555 got its name from the three 5 kΩ resistors used
within, but Hans Camenzind has stated that the number was arbitrary. Low-
power versions of the 555 are also available, such as the 7555 and CMOS
TLC555. The 7555 is designed to cause less supply noise than the classic 555
and the manufacturer claims that it usually does not require a "control"
capacitor and in many cases does not require a decoupling capacitor on the
power supply. Those parts should generally be included, however, because
noise produced by the timer or variation in power supply voltage might

interfere with other parts of a circuit or influence its threshold voltages.

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Pin Diagram:-

The connection of the pins for a DIP package is as follows:

Pin Name Purpose

1 GND Ground reference voltage, low level (0 V)

The OUT pin goes high and a timing interval starts when this input
2 TRIG falls below 1/2 of CTRL voltage (which is typically 1/3 VCC, CTRL
being 2/3 VCC by default if CTRL is left open).

This output is driven to approximately 1.7 V below +VCC, or to

3 OUT
GND.

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 A timing interval may be reset by driving this input to GND, but
4 RESET the timing does not begin again until RESET rises above
approximately
0.7 volts. Overrides TRIG which overrides THR.

Provides "control" access to the internal voltage divider (by

5 CTRL
default, 2/3 VCC).

The timing (OUT high) interval ends when the voltage at THR
6 THR ("threshold") is greater than that at CTRL (2/3 VCC if CTRL is
open).

Open collector output which may discharge a capacitor between

7 DIS
intervals. In phase with output.

Positive supply voltage, which is usually between 3 and 15 V

8 VCC
depending on the variation.

Pin 5 is also sometimes called the CONTROL VOLTAGE pin. By applying a

voltage to the CONTROL VOLTAGE input one can alter the timing
characteristics of the device. In most applications, the CONTROL VOLTAGE
input is not used. It is usual to connect a 10 microf. Capacitor between pin 5
and 0 V to prevent interference. The CONTROL VOLTAGE input can be used
to build an astable multivibrator with a frequency-modulated output.

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 Modes

The IC 555 has three operating modes:

 Bistable mode or Schmitt trigger – the 555 can operate as a flip-flop, if the DIS
pin is not connected and no capacitor is used. Uses include bounce-free latched
switches.
 Monostable mode – in this mode, the 555 functions as a "one-shot" pulse
generator. Applications include timers, missing pulse detection, bouncefree
switches, touch switches, frequency divider, capacitance measurement, pulse-
width modulation (PWM) and so on.
 Astable (free-running) mode – the 555 can operate as an electronic oscillator.
Uses include LED and lamp flashers, pulse generation, logic clocks, tone
generation, security alarms, pulse position modulation and so on. The 555 can
be used as a simple ADC, converting an analog value to a pulse length.

A photo-resistor or light-dependent resistor (LDR) or photocell is a light-

controlled variable resistor. The resistance of a photo-resistor decreases with
increasing incident light intensity; in other words, it exhibits photoconductivity.
A photo- resistor can be applied in light-sensitive detector circuits, and light-
and dark- activated switching circuits.

A photo-resistor is made of a high resistance semiconductor. In the dark, a

photo- resistor can have a resistance as high as several megohms (MΩ), while
in the light, a photo-resistor can have a resistance as low as a few hundred
ohms. If incident light on a photo-resistor exceeds a certain frequency, photons
absorbed by the semiconductor give bound electrons enough energy to jump
into the conduction band. The resulting free electrons (and their hole partners)
conduct electricity, thereby lowering resistance. The resistance range and
sensitivity of a photo-resistor can substantially differ among dissimilar devices.
Moreover, unique photo-resistors may react substantially differently to photons
within certain wavelength bands.

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 LED (Light Emitting Diode):-

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a

p–n junction diode, which emits light when activated. When a suitable voltage
is applied to the leads, electrons are able to recombine with electron holes
within the device, releasing energy in the form of photons. This effect is
called electroluminescence, and the color of the light (corresponding to the
energy of the photon) is determined by the energy band gap of the
semiconductor. an LED is often small in area (less than 1 mm 2) and integrated
optical components may be used to shape its radiation pattern.

Appearing as practical electronic components in 1962, the earliest LEDs

emitted low-intensity infrared light, Infrared LEDs are still frequently used as
transmitting elements in remote-control circuits, such as those in remote
controls for a wide variety of consumer electronics. The first visible-light LEDs
were also of low intensity, and limited to red. Modern LEDs are available
across the visible, ultraviolet, and infrared wavelengths, with very high
brightness.

Early LEDs were often used as indicator lamps for electronic devices, replacing
small incandescent bulbs. They were soon packaged into numeric readouts in
the form of seven-segment displays, and were commonly seen in digital clocks.

Recent developments in LEDs permit them to be used in environmental and

task lighting. LEDs have many advantages over incandescent light sources
including lower energy consumption, longer lifetime, improved physical
robustness, smaller size, and faster switching. Light-emitting diodes are now
used in applications as diverse as aviation lighting, automotive headlamps,
advertising, general lighting, traffic signals, camera flashes and lighted
wallpaper. As of 2015, LEDs powerful enough for room lighting remain
somewhat more expensive, and require more precise current and heat
management, than compact fluorescent lamp sources of comparable output.

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 VARIABLE 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. In electronic
circuits, resistors are used to limit current flow, to adjust signal levels, bias
active elements, and terminate transmission lines among other uses. High-
power resistors, that can dissipate many watts of electrical power as heat, may
be used as part of motor controls, in power distribution systems, or as test loads
for generators. Fixed resistors have resistances that only change slightly with
temperature, time or operating voltage. Variable resistors can be used to adjust
circuit elements (such as a volume control or a lamp dimmer), or as sensing
devices for heat, light, humidity, force, or chemical activity.

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Resistors are common elements of electrical networks and electronic circuits
and are ubiquitous in electronic equipment. Practical resistors as discrete
components can be composed of various compounds and forms. Resistors are
also implemented within integrated circuits.

The electrical function of a resistor is specified by its resistance: common

commercial resistors are manufactured over a range of more than nine orders of
magnitude. The nominal value of the resistance will fall within a manufacturing
tolerance.

The behavior of an ideal resistor is dictated by the relationship specified

by Ohm's law:

Ohm's law states that the voltage (V) across a resistor is proportional to the current
(I), where the constant of proportionality is the resistance (R). For
example, if a 300 ohm resistor is attached across the terminals of a 12 volt
battery, then a current of 12 / 300 = 0.04 amperes flows through that resistor.

Practical resistors also have some inductance and capacitance which will also
affect the relation between voltage and current in alternating current circuits.

The ohm (symbol: Ω) is the SI unit of electrical resistance, named after Georg
Simon Ohm. An ohm is equivalent to a volt per ampere. Since resistors are
specified and manufactured over a very large range of values, the derived units of

milliohm (1 mΩ = 10−3 Ω), kilohm (1 kΩ = 103 Ω), and megohm (1 MΩ = 106

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Ω) are also in common usage.

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Series and parallel resistors

The total resistance of resistors connected in series is the sum of their individual
resistance values.

The total resistance of resistors connected in parallel is the reciprocal of the sum of
the reciprocals of the individual resistors.

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ON/OFF SWITCHES:-
In electrical engineering, a switch is an electrical component that can
break an electrical circuit, interrupting the current or diverting it from one
conductor to another.

The most familiar form of switch is a manually operated electromechanical

device with one or more sets of electrical contacts, which are connected to
external circuits. Each set of contacts can be in one of two states: either
"closed" meaning the contacts are touching and electricity can flow between
them, or "open", meaning the contacts are separated and the switch is non-
conducting. The mechanism actuating the transition between these two states
(open or closed) can be either a "toggle" or "momentary" type.

Fig.No.4.5:- Switches

A switch may be directly manipulated by a human as a control signal to a

system, such as a computer keyboard button, or to control power flow in a
circuit, such as a light switch. Automatically operated switches can be used to
control the motions of machines, for example, to indicate that a garage door has
reached its full open position or that a machine tool is in a position to accept
another work piece. Switches may be operated by process variables such as

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pressure, temperature, flow, current, voltage, and force, acting as sensors in a
process and used to automatically control a system. For example, a thermostat
is a temperature-operated switch used to control a heating process. A switch
that is operated by another electrical circuit is called a relay. Large switches
may be remotely operated by a motor drive mechanism. Some switches are
used to isolate electric power from a system, providing a visible point of
isolation that can be padlocked if necessary to prevent accidental operation of a
machine during maintenance, or to prevent electric shock.

An ideal switch would have no voltage drop when closed, and would have no
limits on voltage or current rating. It would have zero rise time and fall time
during state changes, and would change state without "bouncing" between on
and off positions.

Practical switches fall short of this ideal; they have resistance, limits on the
current and voltage they can handle, finite switching time, etc. The ideal switch
is often used in circuit analysis as it greatly simplifies the system of equations
to be solved, but this can lead to a less accurate solution. Theoretical treatment
of the effects of non- ideal properties is required in the design of large networks
of switches, as for example used in telephone exchanges.

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12 Volt Supply:-

12V power supplies (or 12VDC power supplies) are one of the most common power
supplies in use today. In general, a 12VDC output is obtained from a 120VAC or
240VAC input using a combination of transformers, diodes and transistors. 12V power
supplies can be of two types: 12V regulated power supplies, and 12V unregulated
power supplies.12V regulated power supplies come in three styles: Switching regulated
AC to DC, Linear regulated AC to DC, and Switching regulated DC to DC.

Switching regulated 12VDC power supplies, sometimes referred to as SMPS power

supplies, switchers, or switched mode power supplies, regulate the 12VDC output
voltage using a complex high frequency switching technique that employs pulse width
modulation and feedback. Acopian switching regulated power supplies also employ
extensive EMI filtering and shielding to attenuate both common and differential mode
noise conducted to the line and load. Galvanic isolation is standard in our 12VDC
switchers, affording our users input to output and output to ground isolation for
maximum versatility. Acopian switching regulated power supplies are highly efficient,
small and lightweight, and are available in both AC-DC single and wide-adjust output
and DC-DC configurations. Our Low Profile wide adjust output switchers can be
voltage or current regulated and are externally programmable.

Linear regulated 12VDC power supplies regulate the output using a dissipative
regulating circuit. They are extremely stable, have very low ripple, and have no
switching frequencies to produce EMI. Galvanic isolation is standard in our 12VDC
linears, affording our users input to output and output to ground isolation for maximum
versatility. Acopian linear regulated power supplies are available AC to DC single and
wide adjust outputs.

Unregulated 12VDC power supplies are basic power supplies with an AC input and an
unregulated 12VDC output. The output voltage changes with the input voltage and
load. These power supplies are inexpensive and extremely reliable.

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Typical applications for 12 VDC power supplies:

 Computer Peripherals and Networking Applications

 Telecommunications and Fiber optic Network
 Voice, Data and Analog Communications
 Universities and Educational Facilities
 Instrumentation and Electronics
 Utility and Power Industries
 Data Acquisition
 Medical
 Military
 Motor control

47 K TRIMMERS OR PRESET:-

Trimmer is a miniature adjustable electrical component. It is meant to be set

correctly when installed in some device, and never seen or adjusted by the device's
user. Trimmers can be variable resistors (potentiometers), variable capacitors, or
trimmable inductors. They are common in precision circuitry
like A/V components, and may need to be adjusted when the equipment is
serviced. Trimpots are often used to initially calibrate equipment after
manufacturing. Unlike many other variable controls, trimmers are mounted
directly on circuit boards, turned with a small screwdriver and rated for many
fewer adjustments over their lifetime. Trimmers like trimmable inductors and
trimmable capacitors are usually found in superhet radio and television receivers,
in the intermediate frequency (IF), oscillator and radio frequency (RF) circuits.
They are adjusted into the right position during the alignment procedure of the
receiver.
Presets in electronics are adjustable components to which the user of the device
has no access. They are intended to be set during manufacture or as part of
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 maintenance and repair. A range of different passive components can be made as
presets, including resistors, capacitors, and inductors.

General Considerations

Trimmers come in a variety of sizes and levels of precision. For example, multi-
turn trim potentiometers exist, in which it takes several turns of the adjustment
screw to reach the end value. This allows for very high degrees of accuracy. Often
they make use of a worm-gear (rotary track) or a leadscrew (linear track).The
position on the component of the adjustment often needs to be considered for
accessibility after the circuit is assembled. Both top- and side-adjust trimmers are
available to facilitate this. The adjustment of presets is often fixed in place with
sealing wax after the adjustment is made to prevent movement by vibration. This
also serves as an indication if the device has been tampered with.

330E RESISTOR:-
A resistor is a passive two-terminal electrical component that implements
electrical resistance as a circuit element. Carbon film resistors are a fixed form
type resistor. They are constructed out of a ceramic carrier with a thin pure carbon
film around it, that functions as resistive material. Resistors act to reduce current
flow, and, at the same time, act to lower voltage levels within circuits. In
electronic circuits, resistors are used to limit current flow, to adjust signal levels,
bias active elements, and terminate transmission lines among other uses. 330 ohm
1/4 watt carbon film resistor (CFR) with ±5% tolerance. Color Code: Orange,
Orange, Brown, Golden.

Technical Specifications

 1. Resistance: 330E Ω
 2. Film: Carbon Film
 3. Tolerance: 5%

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 4. Power rating: 1/4 Watt/0.25 watt
 5. Maximum working voltage: 250V

12 VOLT RELAY:-

A relay is an electrically operated switch. Current flowing through the coil of the
relay creates a magnetic field which attracts a lever and changes the switch
contacts. The coil current can be on or off so relays have two switch positions and
most have double throw (changeover) switch contacts as shown in the diagram.

Relays allow one circuit to switch a second circuit which can be completely
separate from the first. For example a low voltage battery circuit can use a relay to
switch a 230V AC mains circuit. There is no electrical connection inside the relay
between the two circuits, the link is magnetic and mechanical.

The coil of a relay passes a relatively large current, typically 30mA for a 12V
relay, but it can be as much as 100mA for relays designed to operate from lower
voltages. Most ICs cannot provide this current and a transistor is usually used to
amplify the small IC current to the larger value required for the relay coil. The
maximum output current for the popular 555 timer IC is 200mA, enough to supply
a relay coil directly.

Relays are usuallly SPDT or DPDT but they can have many more sets of switch
contacts, for example relays with 4 sets of changeover contacts are readily
available. For further information about switch contacts and the terms used to
describe them please see the page on switches.

The animated picture shows a working relay with its coil and switch contacts. You
can see a lever on the left being attracted by magnetism when the coil is switched
on. This lever moves the switch contacts. There is one set of contacts (SPDT) in
the foreground and another behind them, making the relay DPDT.

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 Relay showing coil and switch contacts

The supplier's catalogue or website should show the relay's connections. The coil
will usually be obvious and it may be connected either way round. Relay coils
produce brief high voltage 'spikes' when they are switched off and this can destroy
transistors and ICs in the circuit. To prevent damage you must connect
a protection diode across the relay coil.

Most relays are designed for PCB mounting but you can solder wires directly to
the pins providing you take care to avoid melting the plastic case of the relay.

The relay's switch connections are usually labelled COM, NC and NO:

 COM = Common, always connect to this, it is the moving part of the

switch.
 NC = Normally Closed, COM is connected to this when the relay coil
is off.
 NO = Normally Open, COM is connected to this when the relay coil is on.

Connect to COM and NO if you want the switched circuit to be on when the
relay coil is on.

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Connect to COM and NC if you want the switched circuit to be on when the
relay coil is off.

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4007 DIODE

1N 4007 belongs to the series of 1NXXXX devices. Its an American standard

numbering system standard used for semiconductor devices. This standard has
been adopted globally now. In 1N 4007 the first part 1N indicates single junction
semiconductor. 1N indicates 1 junction whereas N indicates the semiconductor
diode. 4007 is the specific number to indicate the particular diode. From the
electrical point of view, 1N 4007 is compatible with other rectifier diodes. The
diodes belonging to 1N400X series can be replaced by this particular diode. They
are normally used in Embedded Systems Projects. So, let’s get started with
1N4007:

1N4007 is a PN junction rectifier diode. These types of diodes allow only the flow
of electrical current in one direction only. So, it can be used for the conversion of
AC power to DC. 1N 4007 is electrically compatible with other rectifier diodes
and can be used instead of any of the diode belonging to 1N400X series. 1N-4007
has different real life applications e.g. free wheeling diodes applications, general
purpose rectification of power supplies, inverters, converters etc. The particular
diode is shown in the figure below.

A diode is a device which allows current flow through only one direction. That is
the current should always flow from the Anode to cathode. The cathode terminal
can be identified by using a grey bar as shown in the picture above.

For 1N4007 Diode, the maximum current carrying capacity is 1A it withstand

peaks up to 30A. Hence we can use this in circuits that are designed for less than
1A.  The reverse current is 5uA which is negligible. The power dissipation of this
diode is 3W.

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7805 IC

IC 7805 is a 5V Voltage Regulator that restricts the output voltage to 5V

output for various ranges of input voltage. It acts as an excellent component
against input voltage fluctuations for circuits, and adds an additional safety to your
circuitry. It is inexpensive, easily available and very much commonly used. With
few capacitors and this IC you can build pretty solid and reliable voltage regulator
in no time. A Circuit diagram with pinout is given. It also comes with provision
to add heatsink.

The maximum value for input to the voltage regulator is 35V. It can provide a
constant steady voltage flow of 5V for higher voltage input till the threshold limit
of 35V. If the input voltage is near to 7.2V to 12V then it does not produce any
heat and hence no need of heatsink. Higher the input volts - the more it gets heated
up, and excess electricity is liberated as heat from 7805. Hence the provision of
heatsink. IC7805 also comes as smaller SMD component as well.

IC 7805 is a series of 78XX voltage regulators. It’s a standard, from the name the
last two digits 05 denotes the amount of voltage that it regulates. Hence a 7805
would regulate 5v and 7806 would regulate 6V and so on.

The schematic given below shows how to use a 7805 IC, there are 3 pins in IC
7805, pin 1 takes the input voltage and pin 3 produces the output voltage. The
GND of both input and out are given to pin 2.

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BATTERY
The nine-volt battery, or 9-volt battery, in its most common form was
introduced for the early transistor radios. It has a rectangular prism shape with
rounded edges and a polarized snap connector at the top. This type is commonly
used in walkie talkies, clocks and smoke detectors. They are also used as backup
power to keep the time in certain electronic clocks. This format is commonly
available in primary carbon-zinc and alkaline chemistry, in primary lithium iron
disulfide, and in rechargeable form in nickel-cadmium, nickel-metal hydride and
lithium-ion. Mercury oxide batteries in this form have not been manufactured in
many years due to their mercury content. This type is designated NEDA 1604,
IEC 6F22 and "Ever Ready" type PP3 (zinc-carbon) or MN1604 6LR61 (alkaline).

Most nine-volt alkaline batteries are constructed of six individual 1.5V LR61 cells
enclosed in a wrapper. These cells are slightly smaller than LR8D425 AAAA
cells and can be used in their place for some devices, even though they are 3.5 mm
shorter. Carbon-zinc types are made with six flat cells in a stack, enclosed in a
moisture-resistant wrapper to prevent drying.

As of 2007, 9-volt batteries accounted for 4% of alkaline primary battery sales in

the US. In Switzerland as of 2008, 9-volt batteries totalled 2% of primary battery
sales and 2% of secondary battery sales.

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 CHAPTER-6
PCB LAYOUT

PCB LAYOUT

PCB FRONT VIEW PCB BACK VIEW

LAYOUT OF STREET LIGHT CIRCUIT MODEL

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 CHAPTER-7
5. SOLDERING AND DESOLDERING

SOLDERING:-

Soldering is a process in which two or more metal items are joined together by
melting and flowing a filler metal (solder) into the joint, the filler metal having
a lower melting point than the adjoining metal. Soldering differs from welding
in that soldering does not involve melting the work pieces. In brazing, the filler
metal melts at a higher temperature, but the work piece metal does not melt. In
the past, nearly all solders contained lead, but environmental concerns have
increasingly dictated use of lead-free alloys for electronics and plumbing
purposes.

Common solder formulations based on tin and lead are listed below. The
fraction represent percentage of tin first, then lead, totaling 100%:

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 63/37: melts at 183 °C (361 °F) (eutectic: the only mixture that melts at a
point, instead of over a range)
 60/40: melts between 183–190 °C (361–374 °F)
 50/50: melts between 185–215 °C (365–419 °F)

The purpose of flux is to facilitate the soldering process. One of the obstacles to
a successful solder joint is an impurity at the site of the joint, for example, dirt,
oil or oxidation. The impurities can be removed by mechanical cleaning or by
chemical means, but the elevated temperatures required to melt the filler metal
(the solder) encourages the work piece (and the solder) to re-oxidize. This
effect is accelerated as the soldering temperatures increase and can completely
prevent the solder from joining to the work piece. One of the earliest forms of
flux was charcoal, which acts as a reducing agent and helps prevent oxidation
during the soldering process. Some fluxes go beyond the simple prevention of
oxidation and also provide some form of chemical cleaning (corrosion).

Fluxes for soft solder are currently available in three basic formulations:

1. Water-soluble fluxes - higher activity fluxes designed to be removed with water

after soldering (no VOCs required for removal).

2. No-clean fluxes - mild enough to not "require" removal due to their non-
conductive and non-corrosive residue. These fluxes are called "no-clean"
because the residue left after the solder operation is non-conductive and won't
cause electrical shorts; nevertheless they leave a plainly visible white residue
that resembles diluted bird-droppings. No-clean flux residue is acceptable on all 3
classes of PCBs as defined by IPC-610 provided it does not inhibit visual
inspection, access to test points, or have a wet, tacky or excessive residue that may
spread onto other areas. Connector mating surfaces must also be free of flux

residue. Finger prints in no clean residue is a class 3 defect .

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3. Traditional rosin fluxes - available in non-activated (R), mildly activated
(RMA) and activated (RA) formulations. RA and RMA fluxes contain rosin
combined with an activating agent, typically an acid, which increases the
wettability of metals to which it is applied by removing existing oxides. The
residue resulting from the use of RA flux is corrosive and must be cleaned.
RMA flux is formulated to result in a residue which is not significantly
corrosive, with cleaning being preferred but optional.

Flux performance needs to be carefully evaluated; a very mild 'no-clean' flux

might be perfectly acceptable for production equipment, but not give adequate
performance for a poorly controlled hand-soldering operation.

DESOLDERING:-

In electronics, de soldering is the removal of solder and components from a

circuit board for troubleshooting, repair, replacement, and salvage. Specialized
tools, materials, and techniques have been devised to aid in the desoldering
process.

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 D
esoldering tools and materials include the following:

 Solder wick
 Heat guns, also called hot air guns
 Desoldering pump
 Removal alloys
 Removal fluxes
 Heated soldering tweezers
 Various picks and tweezers for tasks such as pulling at, holding, removing, and
scraping components.
 Vacuum and pressure pumps with specialized heater tips and nozzles

 Rework stations, used to repair printed circuit board assemblies that fail factory
test.

Terminology is not totally standardised. Anything with a base unit with

provision to maintain a stable temperature, pump air in either direction, etc., is
often called a "station" (preceded by rework, soldering, desoldering, hot air);
one, or sometimes more, tools may be connected to a station, e.g., a rework
station may accommodate a soldering iron and hot air head. A soldering iron

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with a hollow tip and a spring-, bulb-, or electrically-operated suction pump
may be called a desoldering iron. Terms such as "suction pen" may be used;
the meaning is usually clear from the context.

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PHOTOGRAPH OF AUTOMATIC STREET LIGHT

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 CHAPTER-8
APPLICATIONS
APPLICATIONS

 Street lights can be used for increasing public safety in areas that people use,
such as doorways and bus stops in the night time.
 It can be used in areas where manual switching is difficult such as hilly areas
and dense paths.
 It is used as energy efficient lighting technique for the streets.
 With some modifications it can also be used at home for rooftop lighting.
 It can be used on roads which reduces the accidents.

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 CHAPTER-9
ADVANTAGES AND DISADVANTAGES

Advantages:-
 It saves the electricity by automatic switching of the lights.
 It gets automatically on in dark weather conditions in rainy days.
 Reduces human effort.
 All the components are easily available.
 Circuit is not costly and can be commonly used.
 Easy to install.
 On/off switch is also available in circuit to off the system when not in use for a
long time.

Disadvantages:-
 For efficient working of circuit, the LDR used should be sensitive.
 I.C should not be heated too much while soldering, excess heat can destroy it.
 Opposite polarity of battery can destroy I.C.
 LEDs should be connected in forward bias for circuit to work. So we have to
take care of polarity while connection.
 LDR should be so adjusted that it should not get light from streetlight itself.

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 CONCLUSION

Energy saving is a big issue in the current world and it is very important as it is
being generated by non-renewable sources of energy. This automatic street
light circuit is very efficient energy saver and also user friendly as it also works
in bad weather conditions for the purpose of lighting the streets and roads. The
best part of this project is the automatic switching of the lights without much
human effort and therefore it can be used on a large scale.

30
 REFERENCES
 http://circuiteasy.com/automatic-street-light/

 http://projectabstracts.com/1644/automatic-street-light-control- system.html

 https://en.wikipedia.org/wiki/Street_light

 http://www.pdfmachine.com

 http://www.efymag.com

 http://www.datasheets4u.com

 http://www.eleccircuit.com

 http://www.engineersgauraz.com

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