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SNGCE ECE DEPT Page 1
INTRODUCTION AND OBJECTIVE
We need to save or conserve energy because most of
the energy sources we depend on, like coal and natural gas can’t be
replaced. Once we use them up , they are gone forever. Saving power is
very important, instead of using the power in unnecessary times it should
be switched off. In any city “STREET LIGHT” is one of the major
power consuming factors. Most of the time we see streetlights are on
even after sunrise thus wasting lot of energy. Over here we are avoiding
the problem by having an automatic system which turns on and off the
streetlights at given time or when ambient light falls below a specific
intensity. LDR is used to detect the ambient light. If the ambient light
is below a specific value the lights are turned on.
A light dependent sensors is interfaced to the PIC16f883
microcontroller. When the sensor goes dark the LED will be made on
and when the sensor founds light the LED will be made off.
It clearly demonstrate the working of transistor in saturation
region and cut-off region. The working of relay is also known ,
microcontroller and the code is written in c language in MikroC ide.
Automatic street light system is a simple concept which uses transistor as
a switch. By this system manual works are completely removed . It
automatically switches on lights when the light goes below ambient light .
This is done using LDR which senses the light.
SNGCE ECE DEPT Page 2
This project aims to design an automatic streetlight that works
in both conventional (electrical ) as well as non-conventional ( solar )
energy resources. Using LDR we control the street light, when the LDR
value falls above the threshold value the lights are switched on and when
the value falls below the threshold value the lights are switched off . In
order to save and conserve energy in an efficient way an intensity
controller, based on movement detection is used . This is done using a
pair of sensors ( IR transmitter and IR receiver ), whenever the value
obtained at the receiver is above the previously set threshold value, an
obstacle is identified and the LED connected to the receiver will be
switched on .
SNGCE ECE DEPT Page 3
METHODOLOGY AND LITERATURE SURVEY
This paper proposes an effective scheme for controlling the
wastage of electricity due to streetlights. It reduces the manual effort by
automating the streetlight on the basis of light intensity. The electricity
wastage can be reduced by glowing the light on the basis of movement
detection. Here three parts have been included under this topic for
completed this study. Design architecture is the main block function for
the proposed design. While, the hardware specification will detail out the
components involved in this design from the sensor components until the
controller selection. Software development based on the proposed design
will be detail out in software part where the flow of the system
operation will be detailed out elaborated.
2.2 LITERATURE SURVEY
Hengyu Wu, Minli Tang, propose about The core technology
of the street light control system is an AT89S52 single-chip microcomputer.
It integrates a power circuit, a fault detect circuit, a photosensitive detection
circuit, an infrared detect circuit, an LCD display circuit, a street light
control circuit, an a1ann circuit, a pressed key control circuit and so on.
This system cans automatically turn on or off the lights and controls the
switches according to traffic flow. It expands the fault detect circuit and
the corresponding a1arm circuit. It also has a convenient and flexible
SNGCE ECE DEPT Page 4
button control circuit to switch on and off fictions mentioned above.
Main weakness is that they didn’t say about the working principle behind
the system. It also said to use fault detection circuit which when it is
damaged, the voltage is zero, so it will create a problem. This paper is
and theoretic proof and shows only simulation result but not as a real
time set up experiments. The focus of this paper to build a way for the
framework which may leads to many follow up research activities in the
Low – rate and also plan to investigate the applicability of this proposal
to detect performance.
GongSiliang describes a remote streetlight monitoring system based on
wireless sensor network. The system can be set to run in automatic
mode, which control streetlight according to Sunrise and Sunset
Algorithm and light intensity. This control can make a reasonable
adjustment according to the latitude, longitude and seasonal variation.
Also this system can run in controlled mode. In this mode, we can take
the initiative to control street lights through PC monitor terminal. In
addition, the system integrates a digital temperature – humidity sensor, not
only monitoring the street light real – time but also temperature and
humidity. The system is equipped with the high – power relay output
and can be widely applied in all places which need timely control such
as streets, stations, mining, schools, and electricity sectors and so on. But
in this work a wireless network for street light remote control is
discussed. In particular, the novelty of the proposal is in the location
awareness of nodes, which cannot self - localize themselves. Prototypes
have been built using costly hardware. The capability of the ranging
measurements, the basis for localization, is not characterized and
Showing some problems on the order of one meter. In near future,
location aware routing algorithms will developed that will improve the
efficiency of the network.
SNGCE ECE DEPT Page 5
Street lighting system Gustavo W. Denardin deals about a control network
for a LED street lighting system. The use of LEDs is being considered
promising solution to modern street lighting systems, due to their longer
life time, higher luminous efficiency and higher CRI. The proposed
control network enables disconnection of the street lighting system from
the mains during peak load time, reducing its impact in the distributed
power system automatically consumption, decrease the management cost
and monitor the status information of each street lighting unit. In order to
meet the system requirements, a wireless sensor network based on
IEEE 802.15.4 TM standard is employed. Its network layer is
implemented using geographic routing strategy, which provides slow
overhead and high scalability features. However, due to well - known
drawbacks of the existing techniques, a novel routing algorithm is
proposed. Simulations show that this algorithm leads to a significant
improvement of routing performance when applied to sparse large scale
scenarios, which is the case of street lighting system. Field tests have
been performed on IEEE 802.15.4- compliant wireless
control units. The obtained experimental results show that the proposed
control network is able to meet the requirements of a LED street lighting
system. It mainly deals about safer roadways with intelligent light system
to reduce power consumption. This system has automatic street light
intensity control based on the vehicular movement and switching ON and
OFF of street lights depending on the light ambiance. This will help in
reducing the power consumption during hours of meager road usage. The
street light module is installed consequently for every certain distance.
This paper also aims at reducing road accidents by detecting
consumption of alcohol by the driver. This can be implemented using
alcohol sensor module which contains skin sensor, breath alcohol sensor
SNGCE ECE DEPT Page 6
and proximity sensor. The skin sensor and breadth alcohol sensor detects
the presence of alcohol content and the proximity sensor helps in
detecting any kind of malpractice. The novelty of this paper is to
effectively reduce the energy consumption of the street lights by
controlling the street light’s intensity, sensing both human as well as
vehicular movement and injury and death caused by drunk driving can be
prevented by prior sensing of the alcohol content in drivers by a simple.
Somchai Hiranvarodo describes a comparative analysis of photovoltaic
(PV) street lighting system in three different lamps. Namely, a low
pressure sodium lamp, a high pressure sodium lamp and a fluorescent
lamp have been used for installation in each mast to determine the
suitable system to install in a typical rural area of Thailand. All three
systems have been mounted with the same module type and wattage in
different places within the Rajamangala Institute of Technology,
Thanyaburi district, Pathumthani province of Thailand. An operation of
solar street lighting system can be divided into 2 period of time, namely,
at 18.00-22.00 hours and 05.00-06.00 hours. The design of a control circuit
was experimentally done in this work. Protection of the battery from
damage for deep discharge and overcharge by a controller was also
considered. The life cycle cost analysis (LCCA) is the appropriate method
for comparing three different lamps. The present worth of each system
can be compared and the least cost option selected. LCCA was based on
the key assumptions (year 2002). The results of comparative analysis of
the PV street lighting systems with a fluorescent lamp have been the
appropriate system for installation in a typical rural area of Thailand
when the cost of lamps, system performance and possibility for purchasing
the components of the system have been considered. The results of this
work can he stated that the average luminance in lux of the fluorescent
lamp at design location Pathumthani province of Thailand, has a highest
SNGCE ECE DEPT Page 7
value compared to the low- pressure sodium and high-pressure sodium.
On the other hand, the lifetime of the fluorescent lamp has a shortest
time compared to other lamps. Nevertheless, the aim of this work is to
determine the appropriate system to install in a typical rural area or a
typical rural village of Thailand when the cost of lamps and system
performance and possibility for purchasing the components of the system
are compared. While considering in other areas it is difficult.
A.C.Kalaiarasan deal about solar energy based street light with auto-
tracking system for maximizing power output from a solar system is
desirable to increase the efficiency. In order to maximize the power
output from the solar panels, one needs to keep panels aligned with the
sun. As such a means of tracking the sun is required. This is a far most
cost effective solution than purchasing additional solar panels. It has been
estimated that the yield from solar panels can be increased by 30 to 60
percent by utilizing a tracking system instead of a stationary array. This
paper describes an automatic tracking system which will keep the solar
panels aligned with the sun in order to maximize efficiency. The sun
tracking sensor is the sensing device, which sense the position of the sun
at the time to time continuously and it gives the sensing output to the
amplifier based on light density of the sun. Here the sun tracking sensor
is LDR ( light dependent resistor ). The amplifier unit is used to amplify
the LDR signals, which makes the low level signal into high level
signals and this output is given to the comparator. The LM324 IC is
used as an amplifier. Comparator compares the signals and gives the
command to the AT89C51 microcontroller. The system presented in this
paper will be an efficient method to use the solar energy in remote
areas. This system consumes very low power and high efficient lightning.
We employ the auto sun tracking system; this can improve the energy
stored in battery. This system does not affect the environment because it
SNGCE ECE DEPT Page 8
is pollution free. Our system also consisting of automatic ON, OFF
control of the LED lamp, so there is no manual operation and it
is not required operators.
Radhi Priyasree explains a system to reduce the power consumption of
streetlights by avoiding inefficient lighting which wastes significant
financial resources each year. This is done by dimming the lights during
less traffic hours. For this purpose PIR sensor is used which detects any
movement. This work also aims at reducing the fatal crashes and road
accidents caused due to alcohol consumption. This is done using skin
sensors placed in vehicle doors and also using breadth sensors inside the
vehicle. By implementing this death rates due to drunk driving can be
reduced to a great extent. The prototype has been implemented and
works as expected and will prove to be very useful and will fulfil all
the present constraints if implemented on a large scale. It also aims at
detecting consumption of alcohol by the driver and if it exceeds certain
level it impairs the driver from entering into the vehicle. This prevents
occurrence of accidents or any fatal crashes. This initiative will help the
government to save this energy and meet the domestic and industrial
S.H. Jeong describes about the development of Zigbee based Street
Light Control System which control and monitor status of street lights
installed alongside load. Lights are switched to ON/OFF by this system’s
control command. Its local status information is also monitored by control
system via communication channel. Status information which is monitored
are on/off status information , energy saving mode status, control group
status information and safety related information, etc. To transfer control
command and status information between streetlight control system and
remote street light control terminals which installed at each light pole,
various communication media and communication protocols are using. As
SNGCE ECE DEPT Page 9
communication media, wireless or power lines are used generally. Various
frequency bands from tens of MHz to Rebrands are used for wireless
case. This Street light control system can save maintenance time and
costs and which can improve safety level.
SNGCE ECE DEPT Page 10
Automation, Power consumption and Cost Effectiveness are the
important considerations in the present field of electronics and electrical
related technologies. Industry of street lighting systems are growing
rapidly and going to complex with rapid growth of industry and cities. To
control and maintain complex street lighting system more economically,
various street light control systems are developed. This proposed system
utilizes the renewable technology (Solar) for the sources of light as LED
Lamps instead of generally used street lamps such as High Pressure
Sodium Lamps, etc. The LED technology is preferred as it offers several
advantages over other traditional technologies like energy saving due to
high current luminous efficiency, low maintenance cost, high colour
rendering index, rapid start up speed, long working life etc. This proposed
system makes use of infrared photoelectric sensor (G12-3C3PA) for
SNGCE ECE DEPT Page 11
BLOCK DIAGRAM AND EXPLANATION
4.1 BLOCK DIAGRAM
4.2 BLOCK DIAGRAM EXPLANATION
In this project the list of hardware components used are given
Light Dependent Resistor
SNGCE ECE DEPT Page 12
4.3 HARDWARE DESCRIPTION
Microcontroller ( PIC16f883 ) :-
This section provides an introduction to most common word in
the embedded system “microcontroller”. It is written to familiarize you
with microcontroller terminology and basic microcontroller architecture.
A microcontroller is a single chip, self-contained computer which
incorporates all the basic components of a personal computer on a much
smaller scale. Microcontrollers are often referred to as single chip devices
or single chip computers. The main consequence of the microcontroller’s
small size is that its resources are far more limited than those of a
desktop personal computer. In functional terms, a microcontroller is a
programmable single chip which controls a process or system. Microcontrollers
are typically used as embedded controllers where they control part of a
very larger system such as an appliance, automobile, scientific instrument
or a computer peripheral.
Microcontrollers are designed to be low cost solutions; therefore using
them can drastically reduce part and design costs for a project. Physically, a
microcontroller is an integrated circuit with pins along each side. The pins
presented by a microcontroller are used for power, ground, oscillator, I/O
ports, interrupt request signals, reset and control. In contrast, the pins
exposed by a microprocessor are most often memory bus signals (rather
than I/O ports).
SNGCE ECE DEPT Page 13
A microcontroller has seven main components:
i. Central processing unit (CPU).
iv. Input and Output.
vi. Interrupt circuitry.
Fig. 4.1: The Microcontroller.
Microcontrollers do not function in isolation. As their name suggests
they are designed to control other devices.
SNGCE ECE DEPT Page 14
Fig:4.2 PIC16F883 IC
Microchip manufacture a series of microcontrollers called PIC.
(Peripheral interface controller). There are many different flavours
available, some basic low memory types, going right up through to ones
that have Analogue - To – Digital converters and even PWM built in. A
PIC microcontroller is a processor with built in memory and RAM and
you can use it to control your projects ( or build projects around it). So
it saves you building a circuit that has separate external RAM, ROM and
peripheral chips .
Microchip is providing the 8-bit, 16-bit and the 32 bit
microcontrollers based on the desired application requirement the design
engineer can choose from those. Microchip is also providing the software
for the microcontrollers where the application programs are written
MIKROC IDE, it is also providing the in circuit debugger called MPLAB
The PIC microcontroller used in this project is pic16f883.
These devices feature a 14 bit wide code memory, and an improved 8
level deep call stack. The instruction set differs very little from the
SNGCE ECE DEPT Page 15
baseline devices, but the two additional opcode bit allow 128 registers
and 2048 word of code to be directly addressed. There are a few
additional miscellaneous instructions, and two additional 8 bit literal
instructions, add and subtracts. The mid range core is available in the
majority of devices labelled PIC12 and PIC16.
The first 32 bytes of the register space are allocated to special
purpose registers; the remaining 96 bytes are used for general purpose
RAM. If banked RAM is used, the high 16 registers (0x70-0x7F) are
global, as are a few of the most important special purpose registers,
including STATUS register which holds the RAM bank select bits.
The PIC16f883 features 256 bytes of EEPROM data memory,
self programming, an ICD, two comparators 11 channels of 10 bit analog
to digital converter, 1 capture/compare/PWM and 1 enhanced
capture/compare/PWM functions, a synchronous serial port that can be
configured as either three wire serial peripheral interface (SPI) or the two
wire inter integrated circuit (IC) bus and an enhanced universal
asynchronous receiver transmitter (EUSART). All of these features make
it ideal for more advanced level A/D applications in automotive,
industrial, appliances or consumer applications
SNGCE ECE DEPT Page 16
Special Microcontroller Features:
Precision Internal Oscillator:
Factory calibrated to ±1KHz
Software selectable frequency range of 8 MHz to 32 kHz
Two-Speed Start-Up mode
Fail -safe clock monitoring for critical applications
Clock mode switching during operation for low-power operation
Power-Saving Sleep mode
Power-on Reset (POR)
Selectable Brown-out Reset (BOR) voltage
Extended Watchdog Timer (WDT) with its own on-chip RC oscillator for
In-Circuit Serial Programming™ (ICSP™) via two pins
In-Circuit Debug (ICD) via two pins
High-endurance Flash/EEPROM cell:
SNGCE ECE DEPT Page 17
100,000 erase/write cycle enhanced Flash program memory, typical
1,000,000 erase/write cycle data EEPROM memory, typical
Data EEPROM retention > 40 years
Self-reprogrammable under software control
Programmable code protection
1 input only pin
High sink/source current 25 mA
Interrupt-on-pin change option
TMR0: 8-bit timer/counter with 8-bit pre scaler
TMR1 enhanced: 16-bit timer/counter with pre scaler,
External Gate Input mode and dedicated low-power 32 kHz
TMR2: 8-bit timer/counter with 8-bit period register,
prescaler and postscaler
Capture/Compare/PWM (CCP) module
Enhanced Capture/Compare/PWM (ECCP) module
with auto-shutdown and PWM steering
Master Synchronous Serial Port (MSSP) module
SPI™ mode, I2C™ mode with address mask capability
Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module:
Supports RS-485, RS-232 and LIN compatibility
Auto-wake-up on Start bit
SNGCE ECE DEPT Page 18
Ultra Low-Power Wake-up (ULPWU)
10-bit 11 channel Analog-to-Digital (A/D) Converter
2 Analog Comparator modules with:
Programmable on-chip Voltage Reference (CVREF) module
(% of VDD)
Fixed 0.6 Vref
Comparator inputs and outputs externally accessible
SR Latch mode
Supports RS-485, RS-232 and LIN compatibility
Auto-wake-up on Start bit
Ultra Low-Power Wake-up (ULPWU)
A transformer is an electrical device that transfers electrical
energy between two or more circuits through electromagnetic
induction. Electromagnetic induction produces an electromotive force
within a conductor which is exposed to time varying magnetic
fields. Transformers are used to increase or decrease the alternating
voltages in electric power applications. A varying current in the
transformer's primary winding creates a varying magnetic flux in
the transformer core and a varying field impinging on the
transformer's secondary winding. This varying magnetic field at the
secondary winding induces a varying electromotive force (EMF) or
voltage in the secondary winding due to electromagnetic induction.
Making use of Faraday's Law (discovered in 1831) in conjunction
SNGCE ECE DEPT Page 19
with high magnetic permeability core properties, transformers can
be designed to efficiently change AC voltages from one voltage
level to another within power networks.
Figure 4.3 Transformer
Bridge rectifier :-
A diode bridge is an arrangement of four (or more) diodes
in a bridge circuit configuration that provides the same polarity of
output for either polarity of input.
Figure 4.4 Bridge rectifier
When used in its most common application, for conversion of an
alternating current (AC) input into a direct current (DC) output, it is
known as a bridge rectifier. A bridge rectifier provides full – wave
rectification from a two – wire AC input, resulting in lower cost and
weight as compared to a rectifier with a 3-wire input from a transformer
with a centre - tapped secondary winding.
SNGCE ECE DEPT Page 20
In the diagrams below, when the input connected to the left corner of
the diamond is positive, and the input connected to the right corner is
negative, current flows from the upper power supply terminal to the
right along the red (positive) path to the output, and returns to the lower
supply terminal via the blue (negative) path.
When the input connected to the left corner is negative, and the input
connected to the right corner is positive, current flows from the lower supply
terminal to the right along there (positive) path to the output, and returns to the
upper supply terminal via the blue ( negative ) path. In each case, the upper
right output remains positive and lower right output negative. Since this
is true whether the input is AC or DC, this circuit not only produces a
DC output from an AC input, it can also provide what is sometimes
called “ reverse polarity protection “. That is, it permits normal
functioning of the loads ( wires ) from a DC power source have been
reversed, and protects the equipment from potential damage caused by
Voltage regulator ( 7805 ) :
7805 is a voltage regulator is a member of 78xx series of
fixed linear voltage regulator ICs. The voltage source in a circuit may
have fluctuations and would not give the fixed voltage output. The
voltage regulator IC maintains the output voltage at a constant value.
Thexx in 78xx indicates the fixed output voltage it is designed to
SNGCE ECE DEPT Page 21
provide. 7805 provides +5V regulated power supply. Capacitors of suitable
values can be connected at input and output pins depending upon the
respective voltage levels.
A voltage regulator takes an unregulated input voltage and converts it to
the exact regulated voltage an electronic circuit requires. Voltage
regulators are used in almost every electronic circuit, and the popular
7805 has been used everywhere from computers to satellites, from DVD
player and video games to Arduinos and robots. Even though it was
introduced in 1972 and more advanced regulators are now available, the
7805 is still in use, especially with hobbyists. The 7805 is a common
type of regulator known as a linear regulator. (As its name hints, the
7805 produces 5 volts.) A linear regulator is built around a large
transistor that controls the amount of power flowing to the output , acting
similar to a variable resistor. A drawback of a linear regulator is that all
the "extra" voltage gets converted into heat. If you put 9 Vinto a linear
regulator and get 5V out, the extra 4V gets turned into heat in the
regulator, so the regulator is only about 56% efficient. Linear regulators
such as the 7805 became very popular because they are extremely easy to
use: just feed the unregulated voltage into one pin, ground the second
pin, and get regulated voltage out the third pin. Another feature that
made the 7805 popular is it is almost indestructible - if you short-circuit
it, put too much voltage in, or run it too hot, it will shut down before
getting damaged, due to internal protection circuits.
SNGCE ECE DEPT Page 22
Figure 4.5 Regulator
Light dependent resistor ( LDR ) :-
Light dependent resistors are very useful especially in light or dark
sensor circuits. Normally the resistance of an LDR is very high, but
when they are illuminated with light, resistance drops dramatically.
Electronic onto sensors are the devices that alter their electrical
characteristics, in the presence of light. The best known devices of
this type are the light dependent resistors, the photodiode and
phototransistors. As the name suggest, depending on light the
resistance value varies.
LDR are made by depositing a film of cadmium sulphide or cadmium
selenite on a substrate of ceramic containing no or very free electrons
when not illuminated. The longer strip the more the value of
resistance. When light falls on the strip the resistance decreases. In the
absence of light the resistance can be in the order of 10Kohm to
15Kohm and is called dark resistance. Though LDR is very sensitive
to light, the switching time is very high and hence cannot be used
for high frequency applications. The below figure shows that when
the torch is turned on, the resistance of the LDR falls, allowing
current to pass-through it is shown in figure given below.
SNGCE ECE DEPT Page 23
Figure 4.6. LDR Figure 4.7 Symbol of LDR
The basic construction and symbol for LDR are shown in above
figures respectively. The device consists of a pair of metal film contacts
separated by a snake like track of cadmium sulphide film, designed to
provide the maximum possible contact area with the two metal films.
The structure is housed in a clear plastic or resin case, to provide free
access to external light. Practical LDRs are available in variety of sizes
and packages styles, the most popular size having a face diameter of
roughly 10mm. Practical LDR is shown in below figure.
Figure 4.7. Practical LDR
IR Sensors :-
An infrared sensor is an electronic device, that emits in order to sense
some of aspects of the surroundings. An IR sensor can measure the
heat of an object as well as detects the motion. These types of
sensors measures only infrared radiations, rather than emitting it that is
called as a passive IR sensor. Usually in the infrared spectrum, all the
SNGCE ECE DEPT Page 24
objects radiate some form of thermal radiations. These types of
radiation are invisible to our eyes, that can be detected by an IR
sensor. The emitter is simply an IR led and the detector is simply an
IR photodiode which is sensitive to IR light of the same wavelength
as that emitted IR led . When IR light falls on the photodiode, the
resistance and the output voltages, change in proportion to the
magnitude of the IR light received. An IR sensor circuit is one of the
basic and popular sensor module in an electronic device. This sensor
is analogous to human visionary senses, which can be used to detect
obstacles and it is one of the common applications in real time.
Figure 4.8. IR sensor pair
Relay:-Relays are elements connected to the output pins of the
microcontroller and are used to turn on/off all that being out off
board which has sensitive components: motors, transformers, heaters,
bulbs, high voltage components etc. There are various types of relays
but all have same operating principles: when a current flows through
the coil, it makes or breaks the electrical connections, between one or
more pair of contacts. As it is case with optocouplers, there is no
galvanic connection ( electrical contact ) between input and output
circuits. Relays usually demands both higher voltage and current to
SNGCE ECE DEPT Page 25
start operating but there are also miniature versions which can be
activated with a low current directly obtained from a microcontroller
Figure 4.9 Relay
In electronics, a diode is a two-terminal electronic component
That conducts primarily in one direction (asymmetric conductance); it
has low (ideally zero) resistance to the flow of current in one direction
, and high (ideally infinite) resistance in the other. A semiconductor
diode, the most common type today, is a crystalline piece of
semiconductor material with a p–njunction connected to two electrical
terminals. The diode can be viewed as an electronic version of a
check valve. This unidirectional behaviour is called rectification, and
is used to convert alternating current to direct current, including
extraction of modulation from radio signals in radio receivers—these
diodes are forms of rectifiers . A semiconductor diode's current–voltage
characteristic can be tailored by selecting the semiconductor materials
and the doping impurities introduced into the materials during
manufacture. These techniques are used to create special – purpose
SNGCE ECE DEPT Page 26
diodes that perform many different functions. In this diode act as a
fly back diode (sometimes called a snubber diode, commutating diode,
freewheeling diode, suppressor diode, suppression diode, clamp diode
or catch diode), it is a diode used to eliminate flyback, which is the
sudden voltage spike seen across an inductive load when its supply
voltage is suddenly reduced or removed.
Figure 4.10. free wheeling diode Figure 4.11 diode
A resistor is a passive two terminal electrical component that
implements electrical resistance as a circuit element. In electronic
circuit, resistors are used to limit current flow, to adjust signal levels,
bias active elements, and terminate transmission line 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.
SNGCE ECE DEPT Page 27
Figure 4.12. Resistors Figure 4.13. Schematic diagram symbols
A capacitor (originally known as condenser) is a passive two
terminal electrical component used to store electrical energy temporarily
in an electric field. The forms of practical capacitor vary widely, but all
contain at least two electrical conductors(plates) separated by a
dielectric(i.e., an insulator that can store energy by becoming polarized).
The conductors can be thin film, foils or sintered beads of metal or
conductive electrolyte, etc. The non- conducting dielectric acts to increase
the capacitors charge capacity. Materials commonly used as dielectrics
include glass, ceramic, plastic film, air, vacuum, paper, mica, and oxide
layers. Capacitors are widely used as parts of electrical circuit in many
common electrical devices. Unlike a resistor, an ideal capacitor does not
dissipate energy. Instead a capacitor stores energy in the form of
electrostatic field between its place. An ideal capacitor is characterized
by a single constant value, its capacitance. Capacitance is defined 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).
Capacitors are widely in electronic circuit for blocking direct current
while allowing alternating current to pass. In analogue filter networks,
SNGCE ECE DEPT Page 28
they smooth the output of power supplies. In resonant circuit they tune
radios to particular frequencies. In electric power transmission system,
they stabilise voltage and power flow.
Figure 4.14. Capacitors Figure 4.15. Schematic diagram
Transistor (BC547) :-
BC547 is an NPN bipolar junction transistors. A transistor, stands for
transfer of resistance, is commonly used to amplify current. A small
current at its base controls a large current at collector and emitter
terminals. BC547 is mainly used for amplification and switching
purposes. It has a maximum current gain of 800. It’s equivalent
transistor are BC548 and BC549. The transistor terminals requires a
fixed DC voltage to operate in the desired region of its characteristic
curves. This is known as biasing. For amplification application, the
transistor is biased such that it is partly ON for all input conditions.
The input signal at base is amplified and taken at the emitter. BC547
is used in common emitter configuration for amplifiers. The voltage
divider is the commonly used biasing mode. For switching
applications, transistor is biased so that it remains fully ON if there is
a signal at its base. In the absence of base signal it gets completely
SNGCE ECE DEPT Page 30
5.1 CIRCUIT DIAGRAM
5.2 CIRCUIT EXPLANATION
Automatic control of street lights is designed to turn on and
turn off street light automatically. This project check the amount of light
and street light is turned on and off. Light sensor is used to detect
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intensity of light. PIC16F883 microcontroller is used to turn on transistor
which in turn energize the relay coil and relay turn switches between
electricity and solar energy to light the street lights
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/*Set LDR pin as input and analog*/
ANSELbits.ANS0 = 1;
/*Set RX1 pin as in put and analog*/
ANSELbits.ANS1 = 1;
/*Set RX2 pin as input and analog*/
ANSELbits.ANS2 = 1;
/*Set Relay pin as output and digital*/
ANSELHbits.ANS12 = 0;
/*Set street light pins as output and digital*/
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RELAY = OFF;
STL1 = OFF;
STL2 = OFF;
6.2 SUB ROUTINES
* Delayfunctions forHI-TECH C on the PIC
* Functions available:
DelayUs(x) : Delay specified number of microseconds
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DelayMs(x) : Delay specifiednumber of milliseconds
* Note that there are range limits: x must not exceed 255 - for
Crystal frequencies > 12 MHz the range for DelayUs is even
smaller . To use DelayUs it is only necessary to include this file ;
to useDelayMs you must include delay . c in your project .
/* Set the crystal frequency in the CPP predefined symbols list in
HPDPIC,oron the PICC command line,
e.g., picc -DXTAL_FREQ= 4MHZ
Note that this is the crystal frequency, theCPU clock is
Divided by 4.
* MAKE SURE this codeis compiled withfull optimization!!!
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# define XTAL_FREQ 20MHZ /* Crystal frequency in MHz */
#define MHZ *1000L /* number of kHz in a MHz */
#define KHZ *1 /* number of kHz in a kHz */
#if XTAL_FREQ>= 12MHZ
#define DelayUs ( x)
unsigned char _dcnt ;
While(--_dcnt != 0)
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unsigned char _dcnt;
While(--_dcnt != 0)
extern voidDelayMs(unsigned char);
extern voidDelaySec(unsigned charcnt);
* Delay functions
See delay.h for details
* Make sure this codeis compiled with full optimization!!!
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# if XTAL_FREQ<= 4MHZ
} while( --cnt);
#if XTAL_FREQ> 2MHZ
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VoidDelaySec ( unsigned charcnt)
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// PIC16F883 Configuration Bit Settings
//'C' source lineconfig statements
//#pragmaconfig statements should precede project file includes.
// Use projectenumsinstead of#define for ON and OFF.
#pragmaconfigFOSC = HS
// Oscillator Selection bits (INTOSCIO oscillator: I/O function on
SNGCE ECE DEPT Page 45
RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN)
#pragmaconfigWDTE = OFF
//WatchdogTimer Enable bit (WDT disabled and can be enabled by
SWDTEN bit of the WDTCONregister)
#pragmaconfig PWRTE= OFF
// Power-up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = ON
// RE3/MCLR pin function select bit (RE3/MCLR pin function is
#pragmaconfigCP = OFF
// CodeProtection bit (Program memory codeprotection is disabled)
#pragmaconfig CPD = OFF
// Data CodeProtection bit (Data memory codeprotection is disabled)
#pragmaconfigBOREN = OFF
//Brown OutReset Selection bits (BOR disabled)
#pragmaconfig IESO = ON
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//Internal ExternalSwitchover bit (Internal/External Switchover mode
#pragmaconfigFCMEN = ON
// Fail – Safe Clock Monitor Enabled bit (Fail – Safe Clock Monitor is
#pragmaconfig LVP = OFF
// Low Voltage Programming Enable bit (RB3 pin has digital I/O, HV
On MCLR must be used for programming)
#pragmaconfigBOR4V = BOR40V
// Brown-out Reset Selection bit (Brown-out Reset set to 4.0V)
#pragmaconfigWRT = OFF
// Flash Program MemorySelf WriteEnable bits ( Write protection
Extern unsignedintread_adc ( unsigned char channel);
SNGCE ECE DEPT Page 50
PCB LAYOUT AND FABRICATION
7.1 PCB FABRICATION
Printed Circuit Board ( PCB ) is piece of art. The performance of an
electronic circuit depends on the design and layout of the PCB. A PCB
mechanically supports and connects components by conductive pathways,
etched from copper sheets laminated on to insulated substrate. PCB are
used to rotate electrical currents and signals through copper tracts which
are firmly bonded to an insulating base.
7.1.1 STEPS FOR PCB FABRICATION
PCB fabrication involves the following steps :
1. Drawing the layout of the PCB in the paper. The track layout of
the electronic circuit should be made in such manner that the paths
are in easy routes. It is then transferred to a Mylar sheet. The sheet
is then touched with black ink.
2. The solder side of the Mylar sheet is placed on the shiny side of
the five–star sheet and is placed in a frame. Then it is exposed to
sunlight with Mylar sheet facing the sunlight.
3. The exposed five–star sheet is put in hydrogen peroxide solution.
Then it is put in hot water and shook till unexposed region
4. This is put in cold water and then the rough side is stuck onto the
silk screen. This is then pressed and dried well.
5. The plastic sheet of the five-star sheet is removed leaving the
pattern on the screen.
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6. A copper clad sheet is cut to the size and cleaned. This is placed
7. As it resistant ink if spread on the screen so that a pattern of
tracks and a pad is obtained on a copper clad sheet. It is then
8. The dried sheet is then etched using Ferric Chloride solution ( 32
Baume ) till all the unwanted copper is etched away. Swish the
board to keep the each fluid moving. Lift PCB and check all the
unwanted copper is removed. Etching is done by immersing the
marked copper clad in a ferric chloride solution. After that the
etched sheet is dried.
9. The unwanted resist is removed using sodium hydroxide solution.
Holes are then dried.
5.1.2 PCB LAYOUT
Figure 7.1 : PCB LAYOUT
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Soldering is the processes of joining metals by using lower melting
point to weld or alloy with the joining surface.
Solder is the joining material that melts below 427 degree
connections between components. The popularly used solders are alloys of
tin ( Sn ) and lead ( Pb ) that melts below the melting point if tin.
1. Rosin core :- 60/40 Sn/Pb solders are the most common types used
for electronics assembly. These solders are available in various
diameters and are most appropriate for small electronics work (
0.02” – 0.05” diameter is recommended )
2. Lead free :- Lead free solders are used as more environmental –
friendly substitutes for leaded solder, but they are typically not as
easy to use mainly because of their higher melting point and
poorer wetting properties.
3. Silver :- Silver solders are typically used for low resistance
connections but they have higher melting point and are expensive
than Sn/Pb solders.
4. Acid - core :- Acid – core solders should not be used for electronic.
They are intended for plumbing of non – electronic assembly work.
The acid – core flux will cause corrosion of the circuitry and can
5. Other special solders :- various melting point eutectics : these
special solders are typically used for non – electronic assembly of
SNGCE ECE DEPT Page 53
difficult to construct mechanical items that must be assembled in a
6. Paste solders :- these solders are used in the field application or in
specialized manufacturing application.
In order to make the surface accept the solder readily, the
components terminals should be cleaned chemically or by abrasion using
blades or knives. Small amount of lead coating can be done on the
portion of the leads using soldering iron, this process is called as
fluxers.These are available in petroleum jelly as paste flux.
The desirable properties of flux are :-
It should provide a liquid cover over the materials and exclude air
gap up to the soldering temperature.
It should dissolve any oxide on the metal surface.
It should be easily replaced from the metal by the molten soldering
Residue should be removed after completing soldering operation.
The most common flux used in hand soldering of electronic
components is rosin, combination of mild organic acids extracted
from pine tree.
It is a tool used to melt the solder and apply it at the joints in
the circuit. It operates in 230V supply. The iron at the tip gets heated
SNGCE ECE DEPT Page 54
while few minutes. 50W and 25W soldering irons are commonly used for
soldering of electronic circuits.
SOLDERING STEPS :
1. Make the layout of the component in the circuit. Plug in the chord
of the soldering irons the main to get heated.
2. Straighten and clean the component leads using a blade or knife.
3. Mount the components on the PCB by bending the leads of the
components. Use nose pliers.
4. Apply flux on the joints and solder the joints. Solder must be in
minimum time to avoid dry soldering and heating up of the
5. Wash the residue using water and brush.
6. Solder joints should be inspected when completed to determine if
they have been properly made.
CHARACTERISTICS OF A GOOD SOLDER JOINTS :
A .Shiny surface
B . Good, smooth fillet
CHARACTERISTICS OF A POOR SOLDER JOINTS :
1. Dull or crystallized surface :- This is an indicator of a cold solder
joint. Cold solder joint result from moving the component after
SNGCE ECE DEPT Page 55
soldering has been removed, but before the solder has hardened.
Cold solder joints may work at first, but will eventually fail.
2. Air Pocket :- Air pocket ( voids ) result from incomplete wetting of
surface, allowing air to be in contact with the connecting metals.
This will cause oxidation of the joints & eventual failure. Blow
holes can occur due to vaporization of moisture on the surface of
the board & existing through the molten solder. Boards should be
clean & dry, prior to soldering. Ethanol ( 100% ) can be used as a
moisture chaser if boards are wet prior to soldering.
3. Dimples :- Dimples in the surface do not always indicate a serious
problem, but they should be avoided since they are precursors to
4. Floaters : Black spots :- Floating in the soldering fillet should be
avoided, because they indicate contamination & potential for failure
as in the case of voids. These black spots usually results from
overheated ( burnt ) Rosin or other contaminants such as burnt wire
insulation. Maintaining a clean tip will help to avoid these
5. Balls :- A solder balls instead of a fillet can occur if the trace was
heated but the leads were not ( vice versa ). This prevents proper
wetting of both surfaces & result in solder being attached to only
one surface ( component of trace ).
6. Excess solder :- Excess solder usage can cover up other potential
problems & should be avoided. It can lead to solder bridge. In
addition, spherical solder joints can result from the application of
too much solder.
SNGCE ECE DEPT Page 56
ADVANTAGES AND DISADVANTAGES
Photo resistors convert light into electricity and are not dependent
on any other force.
LDR’s are sensitive, inexpensive, and readily available devices.
They have good power and voltage handling capabilities, similar to
those of a conventional resistor.
They are small enough to fit into virtually any electronic device
and are used all around the world as a basic component in many
LDR may be connected either way round and no special
precautions are required when soldering.
Can be more complicated to align detector pairs ( IR transmitter and IR
Prescribed system is sensitive to ambient light and require careful
Photo resistors are only sensitive to light and no other force can power it
without risking damage. Also,they are unable to detect low light levels
and may take a few seconds to deliver a charge while their electrons
build up momentum.
SNGCE ECE DEPT Page 57
CONCLUSION AND FUTURE SCOPE
The aim of this project was to design and implement an automatic
street light using PIC16f883 microcontroller, which can be used to avoid
manual operation for switching street light on and off. In order to save
and conserve energy in an efficient manner, street lights are on only when
a movement is detected by a movement detection sensors.This proposed
system is in par with government’s policy of energy conservation by reducing
consumption of electricity and efficient use of energy, so it can be termed as
an innovative project in street lightning that can be implemented in the roads
like state and national highways.
9.2 FUTURE SCOPE
This project has scope for improvement and many enhancements
can be done to make it more reliable and interesting. For example, when a
vehicle or a person meet with an accident street light remains on , a
system can be introduced to inform the respective authorities. Similarly, a
system can be introduced to inform the technicians about the default.
All this will be possible, however, only through innovation, hard work and
above all proper use of technology.
SNGCE ECE DEPT Page 58
8051 MICROCONTROLLER AND EMBEDDED SYSTEMS BY
Electronics for you
IOSR Journal of Electronics and Communication Engineering (IOSR-
International Journal of Innovative Research in Science,
Engineering and Technology
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Issue 2, February 2014