street light control system:by maheshraj
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PROJECT ON STREET LIGHT CONTROL SYSTEM: BSc III YEAR
(AFFILIATED TO BANGALORE UNIVERSITY)
19TH MAIN, 17th B CROSS, Sector-IV, HSR layout, Bangalore-560102DEPARTMENT OF COMPUTER SCIENCE
PROJECT REPORT ON
STREETLIGHT CONTROL SYSTEM
Submitted in Practical Fulfillment of the Requirements for the degree
Of
BACHELOR OF COMPUTER SCIENCE
Submitted byMaheshraj
(10RNS75060)
UNDER THE GUIDANCE OF
Mrs.Gayathri Sudheer(Associate Professor)
THE OXFORD COLLEGE OF SCIENCE BENGALURU
(AFFILIATED TO BANGALORE UNIVERSITY)
19TH MAIN, 17TH B CROSS, Sector-IV, HSR layout, Bangalore- 560102
CERTIFICATE
This is to certify that the project work entitled “STREETLIGHT CONTROL SYSTEM” has been successfully carried out by Maheshraj (10RNS75060) student of 6th semester B.Sc, submitted in the partial fulfillment of requirements prescribed by the Bangalore University for “BACHELOR OF COMPUTER SCIENCE”
course during the year 2012-2013
Under The Guidance Of Head of the Department Mrs.Gayathri Sudheer Mrs.Gayathri Sudheer (Associate Professor) (Department of Electronics) Signature of the Examiner
Date: 1) ………………………………………………….
2) ………………………………………………….
ABSTRACT
2
This project aims at designing and executing the
advanced development in embedded systems for energy
saving of street lights with 8051 Microcontroller, light
depending resistor and IR sensor. Now a days, human has
become too busy and he is unable to find time even to
switch OFF the lights wherever not necessary. This can be
seen more effectively in the case of street lights. The
present system of the project is like,only 50% of the street
lights will be switched ON alternatively in the evening
during sun sets using LDR.There will be an alternate light
system, whenever the vehicle passes on the road it will be
detected by IR sensor and 50% of alternate switched off
lights will be switched ON, and the same lights will be
switched OFF alternatively after the vehicles passes away.
On the next day morning after there is sufficient sun light
on the roads the 50% lights which are switched ON will be
switched OFF automatically using LDR. With this, the power
will be saved up to some extent. This project gives the best
solution for saving 10% to90% of electricity.
CONTENTS
1.INTRODUCTION Aim Objectives
3
Motivations Overview
2.THEORITICAL BACKGROUND
3.PROJECT DESRCIPTION
Block Diagram Circuit Diagram Flowchart Components
4.DESIGN PROCEDURE
5.FABRICATION
6.TESTING AND EVALUATION
7.CONCLUSION AND SCOPE OF FUTURE WORK
8.REFRENCES
CHAPTER-1
Introduction
1.1 AIM:
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The main aim of Automation of street light control system
is:
To result in economy of operation.
Elimination of human error.
We know that the demand of electricity is very high
than demand in our country so, Automatic street light
monitoring and control is to save electricity.
To save electricity which is very important for human
life.
1.2 LEARNING OBJECTIVES:
Development on MIC-89C51: This contains an
automatic movement that can save human errors.
Implementation of important subjects of engineering
studies such as Embedded Systems, Control Systems,
and Machines etc. to the fullest.
1.3 MOTIVATION:
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The main consideration in the present field
technologies are Automation, Power consumption and cost
effectiveness. Automation is intended to reduce man power
with the help of intelligent systems. Power saving is the
main consideration forever as the source of the
power(Thermal, Hydro, Electric etc.,)are getting diminished
due to various reasons.
The main aim of the project is Automation of street
power saving system with LDR & IR sensor, this is to save
the power. We want to save power automatically instead of
doing manual. So its easy to make cost effectiveness. This
saved power can be used in some other cases. So in
villages, towns etc we can design intelligent system for the
usage of street lights.
1.4 OVERVIEW:
An automatic control system is an arrangement of
physical components connected in such a manner so as to
direct or regular itself or some another system i.e. some
controlled condition forming part of the system is
maintained in a prescribed manner.
Automatic control system have influenced the current
way of life. In recent year automatic control systems have
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been rapidly increasing importance in all fields of
engineering. Its application covers a very wide range from
design of precision control devices to design of massive
equipments used for manufacture of steel and other
industries.
CHAPTER-2
Theoretical background
Why we are choosing a Microcontroller?
As it provides on chip microprocessor, RAM, ROM,
Parallel I/O port, Serial I/O port etc. hence its cost is
less, size is less, power consumption is less and speed
is more.
Software development tools like assembler, C compilers
etc are easily available and are easy to upgrade
7
History of the Microcontroller
Introduction
A microcontroller (also MCU or µC) is a computer on a
chip. It is a type of microprocessor emphasizing high
integration, low power consumption, self-sufficiency and
cost-effectiveness, in contrast to a general-purpose
microprocessor (the kind used in a PC). In addition to the
usual arithmetic and logic elements of a general purpose
microprocessor, the microcontroller typically integrates
additional elements such as read-write memory for data
storage, read-only memory, such as flash for code storage,
EEPROM for permanent data storage, peripheral devices,
and input/output interfaces. At clock speeds of as little as a
few MHz or even lower, microcontrollers often operate at
very low speed compared to modern day microprocessors,
but this is adequate for typical applications. They consume
relatively little power (milliwatts), and will generally have
the ability to sleep while waiting for an interesting
peripheral event such as a button press to wake them up
again to do something. Power consumption while sleeping
may be just nanowatts, making them ideal for low power
and long lasting battery applications.
8
Microcontrollers are frequently used in automatically
controlled products and devices, such as automobile engine
control systems, remote controls, office machines,
appliances, power tools, and toys. By reducing the size,
cost, and power consumption compared to a design using a
separate microprocessor, memory, and input/output
devices, microcontrollers make it economical to
electronically control many more processes.
Microcontrollers v/s.Microprocessors
9
MICROPROCESSORS
A microprocessor:
single-chip
contained only CPU
bus is available
RAM capacity, num
of port is selectable
RAM is larger than
ROM (usually)
Microprocessor are
suitable to control
of I/O devices in
designs requiring a
minimum
component
MICROCONTROLLERS
A microcontroller
single-chip contained
CPU, RAM, ROM,
Peripherals, I/O port
Communicate by port
internal hardware is
fixed
ROM is larger than
RAM (usually)
Microcontrollers are
suitable to processing
information in
computer systems.
Microcontroller for Embedded Systems
In the literature discussing microcontrollers, we often see
the term Embedded System. Microcontrollers are widely
used in Embedded System products. An Embedded product
uses a microcontroller to do one task and one task only.
10
In an Embedded System there is only one application
software that is typically burned into ROM and X-86 PC
contains or is connected to various Embedded products
such as keyboard, printer, modem, disk controller, sound
card, CD-ROM driver, mouse and so on. Each one of theses
peripherals has a microcontroller inside it that performs
only one task. .
Why use 8 bit microcontroller
The following features of 8- bit microcontrollers make it
useful to be used for IC testing.
Low cost.
Low power consumption
High speed perform
Represent a transition zone between dedicated, high-
volume, 4-bit micro- controllers and the high
performance 16 bit microcontrollers.
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Bit addressing used for test pin monitoring or program
control flags.
8 – bit word size adequate for many computing tasks
and control or monitoring applications
89c51
• 4K Bytes of In-System Reprogrammable Flash
Memory
• 128 x 8-bit Internal RAM
• Two 16-bit Timer/Counters
• Six Interrupt Sources
12
Pin Configuration
13
PIN DIAGRAM DESCRIPTION
Vcc Supply Voltage
GND Ground
Port 0
Port 0 is an 8-bit open drain bidirectional I/O port. As an
output port, each pin can sink eight TTL inputs. When 1s
are written to port 0 pins, the pins can be used as high
impedance inputs.
Port 0 can also be configured to be the multiplexed low-
order address/data bus during accesses to external
program and data memory. In this mode, P0 has internal
pull-ups.
Port 0 also receives the code bytes during Flash
programming and outputs the code bytes during
program verification. External pull-ups are required
during program verification.
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Port 1
Port 1 is an 8-bit bidirectional I/O port with internal pull-
ups. The Port 1 output buffers can sink/source four TTL
inputs. When 1s are written to Port 1 pins, they are
pulled high by the internal pull-ups and can be used as
inputs. As inputs, Port 1 pins that are externally being
pulled low will source current (IIL) because of the
internal pull-ups.
In addition, P1.0 and P1.1 can be configured to be the
timer/counter 2 external count input
(P1.0/T2) and the timer/counter 2 trigger input
(P1.1/T2EX), respectively, as shown in the following
Table.
Port 1 also receives the low-order address bytes during
Flash programming and verification.
Table I. Alternate Functions of Port 1
15
Port 2
Port 2 is an 8-bit bidirectional I/O port with internal pull-
ups. The Port 2 output buffers can sink/source four TTL
inputs. When 1s are written to Port 2 pins, they are
pulled high by the internal pull-ups and can be used as
inputs. As inputs, Port 2 pins that are externally being
pulled low will source current (IIL) because of the
internal pull-ups.
Port 2 emits the high-order address byte during fetches
from external program memory and during accesses to
external data memory that uses 16-bit addresses
(MOVX @ DPTR). In this application, Port 2 uses strong
internal pull-ups when emitting 1s. During accesses to
external data memory that uses 8-bit addresses (MOVX
16
@ RI), Port 2 emits the contents of the P2 Special
Function Register.
Port 2 also receives the high-order address bits and
some control signals during Flash programming and
verification.
Port 3
Port 3 is an 8-bit bidirectional I/O port with internal pull-
ups. The Port 3 output buffers can sink/source four TTL
inputs. When 1s are written to Port 3 pins, they are
pulled high by the internal
pull-ups and can be used as inputs. As inputs, Port 3
pins that are externally being pulled low will source
current (IIL) because of the pull-ups.
Port 3 receives some control signals for Flash
programming and verification.
Port 3 also serves the functions of various special
features of the AT89S52, as shown in the following
Table.
17
Table II. Alternate Functions of Port 3
RST ( Reset input)
A high on this pin for two machine cycles while the
oscillator is running resets the device. This pin drives
high for 98 oscillator periods after the Watchdog times
out. The DISRTO Bit in SFR AUXR (address 8EH) can be
used to disable this feature. In the default state of bit
DISRTO, the RESET HIGH out feature is enabled.
ALE/PROG
Address Latch Enable is an output pulse for latching the
low byte of the address during accesses to external
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memory. This pin is also the program pulse input
(PROG) during Flash Programming.
In normal operation, ALE is emitted at a constant rate
of 1/6 the oscillator frequency and may be used for
external timing or clocking purposes. Note, however,
that one ALE pulse is skipped during each access to
external data memory.If desired, ALE operation can be
disabled by setting bit 0 of SFR location 8EH. With the
bit set, ALE is active only during a MOVX or MOVC
instruction. Otherwise, the pin is weakly pulled
high.Setting the ALE-disable bit has no effect if the
microcontroller is in external execution mode.
PSEN
Program Store Enable (PSEN) is the read strobe to
external program memory. When the AT89S52 is
executing code from external program memory, PSEN
is activated twice each machine cycle, except that two
PSEN activations are skipped during each access to
external data memory.
EA/Vpp
External Access Enable, EA must be strapped to GND in
order to enable the device to fetch code from external
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program memory locations starting at 0000H up to
FFFFH. Note, however, that if lock bit 1 is programmed,
EA will be internally latched on reset.EA should be
strapped to VCC for internal program executions.This
pin also receives the 12-volt programming enable
voltage (VPP) during Flash programming.
XTAL 1
Input to the inverting oscillator amplifier and input to
the internal clock operating circuit
XTAL 2
Output from the inverting oscillator amplifier.
Special Function Register
A map of the on-chip memory area called the Special
Function Register (SFR) space is shown in Table I
Note that not all of the addresses are occupied, and
unoccupied addresses may not be implemented on the
chip. Read accesses to these addresses will in general
return random data, and write accesses will have an
indeterminate effect.
20
ARCHIECTURE 8951
21
User software should not write 1s to these unlisted
locations, since they may be used in future products to
invoke new features. In that case, the reset or inactive
values of the new bits will always be 0.
Timer 2 Registers:
Control and status bits are contained in registers T2CON
(shown in Table II) and T2MOD for Timer 2. The register
pair (RCAP2H, RCAP2L) is the Capture/Reload registers
for Timer 2 in 16-bit capture mode or 16-bit auto-reload
mode.
Interrupt Registers:
The individual interrupt enable bits are in the IE register.
Two priorities can be set for each of the six interrupt
sources in the IP register.
Dual Data Pointer Registers:
To facilitate accessing both internal and external data
memory, two banks of 16-bit Data Pointer Registers are
22
provided: DP0 at SFR address locations 82H-83H and DP1 at
84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS =
1 selects DP1. The user should ALWAYS initialize the DPS
bit to the appropriate value before accessing the respective
Data Pointer Register.
Power off Flag: The Power off Flag (POF) is located at bit 4
(PCON.4) in the PCON SFR. POF is set to “1” during power
up. It can be set and rest under software control and is not
affected by reset.
Memory Organization
MCS-51 devices have a separate address space for
Program and Data Memory. Up to 64K bytes each of
external Program and Data Memory can be addressed.
Program Memory
23
If the EA pin is connected to GND, all program fetches are
directed to external memory.
On the AT89S52, if EA is connected to VCC, program
fetches to addresses 0000H through 1FFFH are directed
to internal memory and fetches to addresses 2000H
through FFFFH are to external memory.
Data Memory
The AT89S52 implements 256 bytes of on-chip RAM. The
upper 128 bytes occupy a parallel address space to the
Special Function Registers. This means that the upper
128 bytes have the same addresses as the SFR space but
are physically separate from SFR space.
When an instruction accesses an internal location above
address 7FH, the address mode used in the instruction
specifies whether the CPU accesses the upper 128 bytes
of RAM or the SFR space. Instructions which use direct
addressing access the SFR space.
For example, the following direct addressing instruction
accesses the SFR at location 0A0H (which is P2).
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MOV 0A0H, #data
Instructions that use indirect addressing access the upper
128 bytes of RAM. For example, the following indirect
addressing instruction, where R0 contains 0A0H, accesses
the data byte at address 0A0H, rather than P2 (whose
address is 0A0H).
MOV @R0, #data
Note that stack operations are examples of indirect
addressing, so the upper 128 bytes of data RAM is
available as stack space.
Oscillator Characteristics
XTAL1 and XTAL2 are the input and output, respectively, of
an inverting amplifier that can be configured for use as an
on-chip oscillator, as shown in Figure. 2.1Either a quartz
crystal or ceramic resonator may be used. To drive the
device from an external clock source, XTAL2 should be left
25
unconnected while XTAL1 is driven, as shown in Figure 2.2.
There are no requirements on the duty cycle of the external
clock signal, since the input to the internal clocking circuitry
is through a divide-by-two flip-flop, but minimum and
maximum voltage high and low-time specifications must be
observed.
Figure 2.1 Oscillator Connections Figure 2.2 External Clock Drive
Configuration
Idle Mode
26
In idle mode, the CPU puts itself to sleep while all the
on-chip peripherals remain active. The mode is invoked by
software. The content of the on-chip RAM and all the special
functions registers remain unchanged during this mode. The
idle mode can be terminated by any enabled interrupt or by
a hardware reset.
Note that when idle mode is terminated by a hardware
reset, the device normally resumes program execution from
where it left off, up to two machine cycles before the
internal reset algorithm takes control. On-chip hardware
inhibits access to internal RAM in this event, but access to
the port pins is not inhibited.
To eliminate the possibility of an unexpected write to a port
pin when idle mode is terminated by a reset, the instruction
following the one that invokes idle mode should not write to
a port pin or to external memory.
Power-down Mode
In the Power-down mode, the oscillator is stopped, and the
instruction that invokes Power-down is the last instruction
executed. The on-chip RAM and Special Function Registers
27
retain their values until the Power-down mode is
terminated. Exit from Power-down mode can be initiated
either by a hardware reset or by an enabled external
interrupt.
Reset redefines the SFRs but does not change the on-chip
RAM. The reset should not be activated before VCC is
restored to its normal operating level and must be held
active long enough to allow the oscillator to restart and
stabilize.
8051 INSTRUCTIONS
28
SINGLE BIT INSTRUCTIONS;
SETB BIT SET THE BIT =1
CLR BIT CLEAR THE BIT =0
CPL BIT COMPLIMENT THE BIT 0 =1, 1=0
JB BIT, TARGET JUMP TO TARGET IF BIT =1
JNB BIT, TARGET JUMP TO TARGET IF BIT =0
JBC BIT, TARGET JUMP TO TARGET IF BIT =1 & THE
1.1 MOV INSTRUCTIONS :- MOV instruction simply copy the
data from one location to another location.
1.2 MOV D,S ; Copy the data from(S) source to
D(destination)
MOV R0,A ; Copy contents of A into Register R0
MOV R1,A ; Copy contents of A into register R1
MOV A,R3 ; Copy contents of Register R3 into
Accumulator.
29
DIRECT LOADING THROUGH MOV
MOV A,#23H ; Direct load the value of 23H in A
MOV R0,#12H ; direct load the value of 12H in R0
MOV R5,#0F9H ; Load the F9 value in the Register R5
ADD INSTRUCTIONS
ADD instruction adds the source byte to the accumulator (A)
and place the result in the Accumulator.
ADD A,#42H ; By this instructions we add the value 42H in
Accumulator.
ADD A,R3 ; By this instructions we move the data from
register r3 to accumulator and then add the
contents of the register into accumulator .
30
SUBROUTINE CALL FUNCTION
1.2.1.1 ACALL, TARGET ADDRESS ; By this instructions
we call subroutines with a target address within 2k
bytes from the current program counter.
ACALL is a limit for the 2 k byte program counter, but for
upto 64k byte we use LCALL instructions. Note that LCALL is
a 3 byte instruction. ACALL is a two byte instruction.
AJMP stands for absolute jump. It transfers program
execution to the target address unconditionally. The target
address for this instruction must be within 2k byte of
program memory.
LJMP is also for absolute jump. It transfers program
execution to the target address unconditionally. This is a 3
byte instructions LJMP jump to any address within 64 k byte
location.
31
INSTRUCTIONS RELATED TO THE CARRY
1.3JC TARGET ; JUMP TO THE TARGET IF CY FLAG =1
1.4JNC TARGET ; JUMP TO THE TARGET ADDRESS IF CY
FLAG IS = 0
2
3 INSTRUCTIONS RELASTED TO JUMP WITH ACCUMULATOR
3.1.1.1.1JZ TARGET ; JUMP TO TARGET IF A = 0
3.1.1.1.1.1.1 JNZ TARGET ; JUMP IF ACCUMULATOR IS NOT
ZERO.
3.1.1.1.1.1.2 This instruction jumps if register A has a value
other than zero
3.1.1.1.2 INSTRUCTIONS RELATED TO THE ROTATE
3.1.1.1.2.1.1.1 RL A ; ROTATE LEFT THE ACCUMULATOR
By this instruction we rotate the bits of A left. The bits
rotated out of A are rotated back into A at the opposite end.
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3.1.1.1.3RR A :- By this instruction we rotate the contents of
the accumulator from right to left from LSB to MSB.
3.1.1.1.4RRC A : - This is same as RR A but difference is that
the bit rotated out of register first enters in to carry
and then enter into MSB.
3.1.1.1.5RLC A :- ROTATE A LEFT THROUGH CARRY. This
shifts the data from MSB to carry and carry to LSB.
3.1.1.1.6RET :- This is return from subroutine. This
instruction is used to return from a subroutine
previously entered by instructions LCALL and ACALL.
3.1.1.1.7RET1 :- This is used at the end of an interrupt
service routine. We use this instruction after interrupt
routine.
PUSH:- This copies the indicated byte onto the stack and
increments SP. This instruction supports only direct
addressing mode.
POP; POP FROM STACK.
This copies the byte pointed to be SP to the location whose
direct address is indicated, and decrements SP by 1. Notice
that this instructions supports only direct addressing mode.
33
DPTR INSTRUCTIONS
MOV DPTR,#16 BIT VALUE; LOAD DATA POINTER
This instructions load the 16 bit DPTR register with a 16 bit
immediate value
3.1.1.1.8 INC BYTE:-
This instruction adds 1 to the register or memory location
specified by the operand.
INC A
INC Rn
INC DIRECT
3.1.1.1.9 DEC BYTE :-
This instruction subtracts 1 from the byte operand. Note
that CY is unchanged.
DEC A
DEC Rn
DEC DIRECT
DESCRIPTION OF
PROJECT
BLOCK DIAGRAM
34
5V power supply using 7805
Description.
7805 is a 5V fixed three terminal positive voltage regulator
IC .The IC has features such as safe operating area
protection,thermal shut down, internal current limiting
which makes the IC very rugged.Out out currents up to 1A
can be drawn from the IC provided that there is a proper
heat sink.A 9V transformer steps down the main voltage ,
35
Light sensor(LDR)
8051µ
IR sensor
street light LEDs
1A bridge rectifies it and capacitor C1 filters it and 7805
regulates it to produce a steady 5V DC .
Circuit diagram.
Power Supplies:
Types of Power Supply
There are many types of power supply. Most are designed
to convert high voltage AC mains electricity to a suitable
low voltage supply for electronics circuits and other devices.
A power supply can by broken down into a series of blocks,
each of which performs a particular function.
For example a 5V regulated supply:
36
Each of the blocks is described in more detail below:
Transformer - steps down high voltage AC mains to low
voltage AC.
Rectifier - converts AC to DC, but the DC output is
varying.
Smoothing - smooths the DC from varying greatly to a
small ripple.
Regulator - eliminates ripple by setting DC output to a
fixed voltage.
Circuit Diagram
37
FLOW CHART
38
Initialize ports
NO
YES
NO
YES
Components
Regulator:
The regulator (7805) provides circuit designers with an easy
way to regulate DC voltages to 5v. Here 78 stands for
positive and 05 stands for 5 volts. The 7805 is a positive
voltage DC regulator that has only 3 terminals. They are:
Input voltage, Ground, Output Voltage.
39
Object detected?
Is it night?
Switch on LightFor 30 seconds
General Features:
Output Current up to 1A
Short Circuit Protection
Thermal Overload Protection
Capacitors:
A capacitor or condenser is a passive electronic
component consisting of a pair of conductors separated by
a dielectric. When a voltage potential difference exists
between the conductors, an electric field is present in the
dielectric. This field stores energy and produces a
mechanical force between the plates.
In this circuit our capacitor is used to remove ripples. In this
we have used both electrolytic and ceramic capacitor of
various ratings.
Resistors:
40
A resistor is a two-terminal electronic component that
produces a voltage across its terminals that is proportional
to the electric current through it in accordance with Ohm's
law.
Resistors of various ratings are used in this circuit.
Resistance is used in front of led to drop the voltage from
5v which is coming from microcontroller to 3v which is
required by the led to glow.
Microcontroller:
The 89C51 is a low-power, high-performance CMOS 8-bit
microcomputer with 8K bytes of Flash Programmable and
Erasable Read Only Memory (PEROM).
41
LED’s:
A light-emitting diode (LED) is a semiconductor light source.
LEDs are used as indicator lamps in many devices, and are
increasingly used for lighting.
In this we are using led’s to show the level of water in tank.
Transistors:
In this we have used NPN and PNP transistors. NPN
transistor will be used to turn the motor on and PNP to
convert negative voltage to positive voltage.
Crystal oscillator:
42
A crystal oscillator is an electronic circuit that uses the
mechanical resonance of a vibrating crystal of piezoelectric
material to create an electrical signal with a very precise
frequency. This frequency is commonly used to keep track
of time to provide a stable clock signal for digital integrated
circuits
Transformer:
Transformers convert AC electricity
from one voltage to another with
little loss of power. Transformers
Transformer
circuit symbol
Transformer
43
work only with AC and this is one of the reasons why mains
electricity is AC.
Step-up transformers increase voltage, step-down
transformers reduce voltage. Most power supplies use a
step-down transformer to reduce the dangerously high
mains voltage (230V in UK) to a safer low voltage.
The input coil is called the primary and the output coil is
called the secondary. There is no electrical connection
between the two coils, instead they are linked by an
alternating magnetic field created in the soft-iron core of
the transformer. The two lines in the middle of the circuit
symbol represent the core.
Transformers waste very little power so the power out is
(almost) equal to the power in. Note that as voltage is
stepped down current is stepped up.
44
LDR:
Light Dependent Resistor – it is a passive light
transducer. it is also called as photo-conductive
cell because its conductivity changes due to change in light
intensity.
LDR’s or light dependent resistors are very useful
especially in light/dark sensor circuits. normally the
resistance of an LDR is very high, sometimes as high as
1000 000 ohms, but when they are illuminated with light
resistance drops dramatically.
45
When a light level of 1000 Lux (bright light) is directed
towards it, the resistance is 400r (ohms).
When a light level of 10 Lux (very low light level) is
directed towards it, the resistance has risen dramatically to
10.43m (10430000 ohms).
Basic principle – when light falls on it its
resistance decreases and when it is dark its
resistance is maximum. the change in
resistance is directly proportional to intensity of light falling
on it.
construction – it is made up of photo sensitive material like
cadmium sulphide (cds), selenium (se), cadmium selenide
(cdse) or lead sulphide (pbs). it is deposited on insulating
surface like ceramic substrate in the form of zigzag wire as
shown in following figure. it is enclosed in round metallic or
plastic case and two electrodes are taken out for external
connections. the structure is covered with glass sheet to
protect it from moisture and dust and allows only light to
fall on it.
46
Constructional diagram of LDR
Applications –
1. It is used in burglar alarm to give alarming sound when
a burglar invades sensitive premises.
2. It is used in street light control to switch on the lights
during dusk (evening) and switch off during dawn
(morning) automatically.
3. It is used in Lux meter to measure intensity of light in
Lux.
4. It is used in photo sensitive relay circuit
IR-SENSORS:
Infrared Radiation
47
Infrared radiation exists in the electromagnetic
spectrum at a wavelength that is longer than visible light. It
cannot be seen but it can be detected. Objects that
generate heat also generate infrared radiation and those
objects include animals and the human body whose
radiation is strongest at a wavelength of 9.4um. Infrared in
this range will not pass through many types of material that
pass visible light such as ordinary window glass and plastic.
However it will pass through, with some attenuation,
material that is opaque to visible light such as germanium
and silicon. An unprocessed silicon wafer makes a good IR
window in a weatherproof enclosure for outdoor use. It also
provides additional filtering for light in the visible
range. 9.4um infrared will also pass through polyethylene
which is usually used to make Fresnel lenses to focus the
infarared onto sensor elements.
Pyroelectric Sensors
The pyroelectric sensor is made of a crystalline material
that generates a surface electric charge when exposed to
heat in the form of infrared radiation. When the amount of
radiation striking the crystal changes, the amount of charge
also changes and can then be measured with a sensitive
FET device built into the sensor. The sensor elements are
sensitive to radiation over a wide range so a filter window is
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added to the TO5 package to limit detectable radiation to
the 8 to 14mm range which is most sensitive to human
body radiation.
Typically, the FET source terminal pin 2 connects through a
pulldown resistor of about 100 K to ground and feeds into a
two stage amplifier having signal conditioning circuits. The
amplifier is typically bandwidth limited to below 10Hz to
reject high frequency noise and is followed by a window
comparator that responds to both the positive and negative
transitions of the sensor output signal. A well filtered power
source of from 3 to 15 volts should be connected to the FET
drain terminal pin 1.
The PIR325 sensor has two sensing elements connected in a
voltage bucking configuration. This arrangement cancels
signals caused by vibration, temperature changes and
sunlight. A body passing in front of the sensor will activate
first one and then the other element whereas other sources
will affect both elements simultaneously and be cancelled.
The radiation source must pass across the sensor in a
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horizontal direction when sensor pins 1 and 2 are on a
horizontal plane so that the elements are sequentially
exposed to the IR source. A focusing device is usually used
in front of the sensor
The figure below shows the PIR325 electrical
specifications and layout in its TO5 package. Note the wide
viewing angle without an external lens.
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This is a typical application circuit that drives a relay.
R10 and C6 adjust the amount of time that RY1 remains
energized after motion is detected.
Fresnel Lens
A Fresnel lens (pronounced Frennel) is a Plano Convex lens
that has been collapsed on itself to form a flat lens that
retains its optical characteristics but is much smaller in
thickness and therefore has less absorption losses.
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Our FL65 Fresnel lens is made of an infrared transmitting
material that has an IR transmission range of 8 to 14um
which is most sensitive to human body radiation. It is
designed to have its grooves facing the IR sensing element
so that a smooth surface is presented to the subject side of
the lens which is usually the outside of an enclosure that
houses the sensor.
The lens element is round with a diameter of 1 inch and has
a flange that is 1.5 inches square. This flange is used for
mounting the lens in a suitable frame or enclosure.
Mounting can best and most easily be done with strips of
Scotch tape. Silicone rubber can also be used if it overlaps
the edges to form a captive mount.
The FL65 has a focal length of 0.65 inches from the lens to
the sensing element. It has been determined by experiment
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to have a field of view of approximately 10 degrees when
used with a PIR325 Pyroelectric sensor.
This relatively inexpensive and easy to use Pyroelectric
Sensor and Fresnel Lens can be used in a variety of science
projects, robots and other useful devices.
CHAPTER-4
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DESIGN PROCEDURE
According to circuit diagram we have collected
the components required in our project.
Then we assembled those components on the pcb
board according to circuit diagram.
After the assembling of these components then
we soldered those components on the pcb board.
We made the hardware connections with the
various components.
Then we assembled the whole hardware on the
plywood.
CHAPTER-5
FABRICATION TECHNIQUES
The fabrication techniques used in this project can
be broadly classified into:
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Mechanical Fabrication, consisting of
mechanical design i.e. board, street, light
poles etc.
Electrical Fabrication, consisting of electrical
design i.e. making PCB, soldering etc.
Mechanical Fabrication
For the basic board we are using plywood cut out
accordingly so as to adjust the PCB on the top, the
transformer, street, LDR, IR sensor, LED poles.
Electrical Fabrication
1)Soldering
How to solder?
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Mount components at their appropriate place; bend the
leads slightly outwards to prevent them from falling out
when the board is turned over for soldering. No cut the
leads so that you may solder them easily. Apply a small
amount of flux at these components leads with the help
of a screwdriver. Now fix the bit or iron with a small
amount of solder and flow freely at the point and the
P.C.B copper track at the same time. A good solder joint
will appear smooth & shiny. If all appear well, you may
continue to the next solder connections.
Tips for good soldering
1. Use right type of soldering iron. A small efficient
soldering iron (about 10-25 watts with 1/8 or 1/4
inch tip) is ideal for this work.
2. Keep the hot tip of the soldering iron on a piece of
metal so that excess heat is dissipated.
3. Make sure that connection to the soldered is clean.
Wax frayed insulation and other substances cause
poor soldering connection. Clean the leads, wires,
tags etc. before soldering.
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4. Use just enough solder to cover the lead to be
soldered. Excess solder can cause a short circuit.
5. Use sufficient heat. This is the essence of good
soldering. Apply enough heat to the component lead.
You are not using enough heat, if the solder barely
melts and forms a round ball of rough flaky solder. A
good solder joint will look smooth, shining and
spread type. The difference between good & bad
soldering is just a few seconds extra with a hot iron
applied firmly.
Precautions
1. Mount the components at the appropriate places
before soldering. Follow the circuit description and
components details, leads identification etc. Do not
start soldering before making it confirm that all the
components are mounted at the right place.
2. Do not use a spread solder on the board, it may
cause short circuit.
3. Do not sit under the fan while soldering.
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4. Position the board so that gravity tends to keep the
solder where you want it.
5. Do not over heat the components at the board.
Excess heat may damage the components or
board.
6. The board should not vibrate while soldering
otherwise you have a dry or a cold joint.
CHAPTER-6
TESTING AND EVALUATION
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All the components used in constructing the
AUTOMATION OF STREET LIGHT CONTROLLER CIRCUIT
came pre tested therefore the tests performed were done
after the completion of the project.
The following tests were performed:
Visual Observation
A visual observation of the AUTOMATION OF STREET
LIGHT CONTROL SYSTEM CIRCUIT was conducted to
look for any broken connection or any stray wire that
can restrict for the ON & OFF function of lights or any
other visible fault.
No problem was found during this visual evaluation.
Operational Test
The circuit was operated and checked whether it is
performing the desired operation. No problem was
found during this test.
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CHAPTER-7
CONCLUSION
AND
SCOPE OF FUTURE WORK
Automatic Street Light Control System is a simple and
powerful concept, which uses transistor as a switch to
switch ON and OFF the street light automatically. By using
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this system manual works are removed. It automatically
switches ON lights when the sunlight goes below the visible
region of our eyes. It automatically switches OFF lights
under illumination by sunlight. This is done by a sensor
called Light Dependant Resistor (LDR) which senses the
light actually like our eyes.
By using this system energy consumption is also reduced
because now-a-days the manually operated street lights are
not switched off properly even the sunlight comes and also
not switched on earlier before sunset. In sunny and rainy
days, ON time and OFF time differ significantly which is one
of the major disadvantage of using timer circuits or manual
operation.
This project exploits the working of a transistor in saturation
region and cut-off region to switch ON and switch OFF the
lights at appropriate time with the help of an
electromagnetically operated switch.
Automatic Streetlight needs no manual operation of
switching ON and OFF. The system itself detects whether
there is need for light or not. When darkness rises to a
certain value then automatically streetlight is switched ON
and when there is other source of light, the street light gets
OFF. The extent of darkness at which the street light to be
switched on can also be tailored using the potentiometer
provided in the circuit.
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CHAPTER-8
REFERENCESFollowing are some internet sites, books, magazines taken
as reference for this project
http://www. electronicsforu.com
http://www.microcontrollerbooks.com
www.8051projects.info/datasheets/ BC548 .pdf
http://www.electronic-circuits-diagrams.com/
alarmsimages/alarmsckt6.shtml
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www.electronicstutotials.com/oscillators/
crystal- oscillators.htm
Books:
Programming and Customizing 8051
Microcontroller by :Myke Predko
The 8051/8052 Microcontroller by: Craig
Steiner
Embedded Systems by Dr. K.V.K.K Prasad
The 8051 Microcontroller Architecture
Programming and Applications by: Kenneth J.
Ayala, West Publishing Company.
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