Design And Construction Of A Shadow Detector With An Alarm

ABSTRACT

This work is titled design and construction of a shadow detector with an alarm. This system sounds an alarm whenever a shadow falls on it. Shadow alarms are widely used for security purposes. Project can be easily installed on the windows and doors. This circuit demonstrates the principle and operation of a simple shadow alarm using LDR. So it can be used at night by shopkeepers to protect the valuables in their showrooms. A dim lighting in the room is necessary to detect the moving shadow. Unlike opto-interruption alarms based on light-dependent resistors (LDRs), it does not require an aligned light beam to illuminate the photo-sensor.

The circuit is powered by a 9V power supply and uses the most sensitive photo-sensor L14F1 to detect shadows. It is portable and can be used at any place that is to be monitored.

TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRCT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• AIM/OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• DEFINITION OF RELATED TERMS
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0     LITERATURE REVIEW

2.1     LITERATURE SURVEY OF THE STUDY

2.2     HISTORICAL BACKGROUND OF THE STUDY

CHAPTER THREE

3.0      CONSTRUCTION METHODOLOGY

3.1      BLOCK DIAGRAM OF THE SYSTEM

3.2     CIRCUIT DIAGRAM

3.3     CIRCUIT DESCRIPTION

3.4     SYSTEM OPERATION

3.5      COMPONENTS LIST

3.6     DESCRIPTION OF MAJOR COMPONENTS USED

CHAPTER FOUR

4.0       RESULT ANALYSIS

4.1     CONSTRUCTION PROCEDURE AND TESTING

4.2     ASSEMBLING OF SECTIONS

4.3     CONSRUCTION OF THE CASING

4.4     TESTING OF SYSTEM OPERATION

4.5    INSTALLATION OF THE COMPLETED DESIGN

4.6    COST ANALYSIS

CHAPTER FIVE

• CONCLUSIONS
• RECOMMENDATION

5.3     REFERENCES

CHAPTER ONE

1.1                                          INTRODUCTION

The need for having home protection has always been there. But in the recent times, considering a dramatic rise in petty crimes like robbery and theft, the need has been more strongly felt to have a fool proof protection of the belongings and the family members. Home security has come a long way in the last few decades. It was in the hands of a guard who manually provided surveillance during nights in the earlier days, but it was not fool proof as it was only normal for him to have momentary lapse of concentration.

The guard was also susceptible to sleep at times. It was then that home alarm system based upon electronic circuits were developed which proved to be highly reliable and were appreciated by the people as they were relieved from constant monitoring of their homes.

This shadow alarm system uses lm741 IC which was wired in an inverting mode, IC 741 was the most common Operational Amplifiers. as tone generator and amplifier to obtain a maximum audible sound. The lm741 IC power that is sent is to transistor which amplifies a loud speaker or buzzer.

The first chapter of this project is narrating on the introduction, the concept of the system and also the aims and objective. Chapter two is all about literature review. Chapter three talks about construction in full. Chapter four is on result analysis. Chapter five is conclusion, recommendation and References.

1.2                                    AIM AND OBJECTIVE

The main aim and objective of the design and construction this project is to create a comfort in the minds of house and property owners when they out from their premises without much fear of intruder.

1.3                             SIGNIFICANCE OF THE PROJECT

This device functions as an electronics watch dog. This device functions as a major security alarms  used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders.

1.4                               LIMITATION OF THE STUDY

• The only problem noticed in this work is that even the shadow of animals can also trigger the device just as human being shadow can also.

1.5                                                 SCOPE OF THE PROJECT

A shadow detector is an electronic  consisting of LDR, transistor and Relay as connected in the main circuit, as shown below.

The circuit shown below requires a DC voltage, which can be supplied from mains by using a bridge rectifier instead of the battery. The bridge rectifier uses a step-down transformer to step-down the 230v into 12v.

This circuit is to switch ON or OFF the light when the LDR is covered by darkness or illuminated. The light dependent resistor will have high resistance in darkness and low resistance in the light. The comparator used here has LDR connected to its inverting terminal and potentiometer connected to its non-inverting pin.

When the shadow falls on the Light Dependent Resistor, the comparator compares the voltages at the reference pin that is with the non-inverting pin and the inverting pin of the op-amp. If the voltage at the non-inverting pin is greater than the voltage at the inverting pin the transistor cannot be switched. If the voltage at non-inverting pin is less than the voltage at the inverting pin, the output of the comparator can switch the transistor.

1.6                                         APPLICATIONS OF THE PROJECT

• Useful for automatic outdoor lighting or garden lighting at home.
• Useful for automatic switching of street lights.
• Useful for switching the hoardings on and off automatically.
• Useful for self-switching operation of displaying title hoardings of companies.
• Useful as a light detector circuit when the pin of the ic is reconfigured.
• Useful as a dark activated switch.

1.7                                        DEFINITION OF RELATED TERMS

• Dispersion – to spread or scatter. The separating out of different wavelengths of white light into a spectrum of colours as it passes through a prism or drop of water or similar transparent object.
• Emit – to give off something as in the sun giving off light.
• Light – a form of energy that is emitted by the sun or by a chemical reaction to which the eye is sensitive.
• Luminescent – to glow or to give off light at low temperatures, as in fireflies.
• Magnify – to make small things look bigger by looking at them through one or more convex lenses.
• Opaque – a material that does not let light pass through. Wood, some plastic and metal objects are opaque.
• Reflect – to bounce off a surface, as in light bouncing off a mirror.
• Refraction – the bending of a light ray as it passes from one medium to another.
• Shadow – a dark image or figure cast on the ground or some surface by an object blocking incoming light.
• Translucent – a material that allows some light to pass through but scatters the light in the process so that images are not clear (i.e. frosted glass)
• Transparent – a material that lets light pass through it so that objects can be seen clearly on the other side
• Visible spectrum – a band of colours that make up visible light; each colour is generated by a different wavelength of light – the longest being red and the shortest being violet
• White light – light that contains ALL the wavelengths of colour in the visible spectrum from red to violet

1.8                                        PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a shadow detector. In this chapter, the background to a shadow detector, significance to a shadow detector, objective limitation and problem of to a shadow detector were discussed.

Chapter two is on literature review of to a shadow detector. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.