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:

4

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:

5

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

6

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.

11

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.

14

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

18

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

19

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).

24

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.

32

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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