DESIGN AND CONSTRUCTION OF A LIGHT DETECTOR

ABSTRACT

A light detector is used to detect the presence of light in a particular area where it is placed, on detection of light (either sunlight or illumination from LEDs) it gives a notification to confirm the presence of light, this notification is based on the design or purpose as the case may be (either raising an alarm or activating another circuit or device).  This device is applicable in areas like fire detection, solar tracking, automatic garden light control, street light control and mostly in the solar world. A LDR (light dependent resistor) light sensor is a variable resistor. In this case we use a pull-up resistor (which means that it is located before the sensor).                                              

TABLE OF CONTENTS

Pages

Title page                                                                                  i

Certification                                                                                ii

Dedication                                                                                 iii

Acknowledgment                                                                        iv-v

Abstract                                                                                     vi

Table of contents                                                                                vii-ix

CHAPTER ONE

1.0    INTRODUCTION                                                                 1

1.1    BACKGROUND OF THE STUDY                                             2

AIMS AND OBJECTIVES                                 

1.2    AIMS OF THE PROJECT                                                       2

1.3    OBJECTIVE OF THE PROJECT                                               5

1.4    SCOPE OF THE PROJECT                                                    6

CHAPTER TWO

2.0    LITERATURE REVIEW                                                          7

TYPES OF LIGHT DETECTORS                                                

2.1.0 PHOTO TRANSISTOR                                                          9

2.1.1 AVALANCHE PHOTO DIODE                                                  11

2.1.2 PHOTO MULTIPLIER TUBE                                                   13

2.1.3 OPTICAL HETERODYNING                                                   16

2.1.4 FUTURE DETECTORS                                                          18

2.1.5 DETECTOR NOISE                                                              19

2.1.6 MINIMUM DETECTABLE LIGHT LEVELS                                  22

2.1.7 LIGHT DEPENDENT RESISTOR                                             23

2.1.8 PHOTO RESISTOR OR LIGHT DEPENDENT RESISTOR (LDR)    25

2.1.9 APPLICATIONS OF LDR                                                        28

CHAPTER THREE: METODOLOGY

3.0 MODE OF OPERATION OF A LIGHT DETECTOR                         29

3.1 POWER SUPPLY STAGE                                                          30

3.2 THE LIGHT SENSING SECTION                                                       32

3.3 RECOVERY RATE                                                                   32

3.4 PROJECT TESTING                                                                        33

3.5 ASTABLE TIMER/ ALARM STAGE                                              34

3.6 BLOCK DIAGRAM EXPLANATION                                              36

CHAPTER FOUR

4.0 OVERVIEW                                                                           38

4.1 LIGHT DEPENDENT RESISTOR                                                       38

4.2 COMPONENTS USED   (LIGHT DETECTOR)                                       41

CHAPTER FIVR

5.0 SUMMARY, CONCLUSION AND RECOMMENDATION                   42

5.1 SUMMARY                                                                            42

5.2 CONCLUSION                                                                        43

5.3 RECOMMENDATION                                                               43

      REFERENCES                                                                       45-46

CHAPTER ONE

1.0 INTRODUCTION
Automatic Streetlight needs no manual operation for switching ON and OFF when there is need of light. It detects itself weather 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 i.e. day time, the street light gets OFF. The sensitiveness of the street light can also be adjusted. In our project we have used four L.E.D for indication of bulb but for high power switching, one can connect Relay (electromagnetic switch) at the output of pin 1 of I.C LM358 Then it will be possible to turn ON/OFF any electrical appliances connected all the way through relay. Detecting light has many uses in the world of robotics. We use light detection in many of our competitions to find markers that lead us around the course or to identify a burning fire that we can put out. This article will cover how to make a few simple light detection circuits for you

a.       BACKGROUND OF THE STUDY

We conducted a background study through interviews with two key informants. 

These two Interviews provided us with a comparison of various forms of light sensor usage on     campus.

Discovering information regarding light sensor use in a place that we spend much of our time truly allowed us to understand the considerations to be made much better.

AIMS AND OBJECTIVES

1.2   AIMS OF THE PROJECT

This project aims at designing and executing the advanced development in embedded systems for energy saving of street lights with light depending resistor. Nowadays, human beings have become too busy to that they are unable to find time even to switch the lights wherever it’s necessary. This can be seen more effectively in the case of street lights. The present system is like, the street lights will be switched on in the evening before the sun sets and they are switched off the next day morning after there is sufficient light on the roads. But the actual timings for these street lights to be switched on are when there is absolute darkness. With this, the power will be wasted up to some extent. This project gives the best solution for electrical power wastage. Also the manual operation of the lighting system is completely eliminated.

In our project we are using LDR, which varies according to the amount of light falling on its surface, this give an indication for us whether it is a day/night time. We have placed IR sensors in both sides of the road, which can be controlled by Micro controller (AT89C51).The IR‘s will be activated only on the night time. If any obstacle crosses the IR, automatically particular light will be ON, for few seconds.

In our project we use regulated 5V, 500mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac output of secondary of 230/12V step down transformer.

The programming language used for developing the software to the microcontroller is Embedded/Assembly. The KEIL cross compiler is used to edit, compile and debug this program. Here in our application we are using AT89C51 microcontroller which is Flash Programmable IC.AT represents the Atmel Corporation ‘C’ represents CMOS technology is used for designing the IC.

 We believe that our idea provides better than the existing system.
In the present project street lights are taken into consideration where the above discussed factors are rectified in them. This is achieved with the help of an embedded system. By using this as the basic principle we can design centralized intelligent system for the perfect usage of streetlights in any place (Via Village, Town) can be developed.

1.3   OBJECTIVE OF THE PROJECT

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 etc.,)are getting diminished due to various reasons.

The main aim of the project is Automatic street power saving system with LDR; this is to save the power. We want to save power automatically instead of doing manual. So it’s easy to make cost effectiveness. This saved power can be used in some other cases. So in villages, towns etc we can design intelligent systems for the usage of street lights.

The guiding objectives of this study were:

·        To determine social beliefs and concerns regarding light sensor usage.

·        To determine the economic feasibility of installing light sensors.

1.4   SCOPE OF THE PROJECT

The main scope of the project is to learn the picture microcontroller, using 10BIT ADC serial communication, interfacing the 16x2 LCD module, and effective use of the MIKROC IDE.