Design And Construction Of A Dark Activated Switch Using Light Dependent Resistor

This work is aimed at activating a switch or AC lamp at sunset and deactivate it at sunrise.

This Dark activated Switch can trigger a relay to operate an AC lamp at Sunset. The lamp remains on till morning and then turns off. This eliminates the need of switching the Porch lamp or Backyard lamp daily and also helps to light the premises of the house when the occupants are out of station.

The circuit utilizes the light sensing property of LDR to activate the circuit. The LDR (Light Dependent Resistor) has very high resistance as high as 10 Meg ohms in dark which reduces to a few Ohms in bright light.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRCT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE PROJECT
• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• METHODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0      LITERATURE REVIEW

2.1     REVIEW OF LIGHT SENSOR

2.2      LDR STRUCTURE AND WORKING

2.3     REVIEW OF THE MAJOR COMPONENTS USED

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

1.0                                                        INTRODUCTION

1.1                                         BACKGROUND OF THE PROJECT

The controlling of lights such as security light is usually done by the occupant of the house. This is not only precarious but also sometimes results in wastage of power because of the negligence or unusual circumstances on part of the technician in operating the lights on and off. Not only in case of security lights, even for controlling the home appliances like garden or outdoor lights, we can utilize the dark activated switch for automatic switching of the lights based on daylight’s intensity by using a light sensor.

Dark Activated Switch is a electrical project circuit by which we can switch on and off the electrical load appliances like lights, fans, coolers, air conditioners, street lights, etc., automatically based on the day-light intensity instead of manually operating the switches.

By using this method, manpower can be reduced to a great extent. In case of the street lights/lamp erected on highways it is not an easy task to manually control them, but, if uncontrolled, the chances of power wastage would increase. To get rid of this situation, the implementation of automatic light switch by using a dark sensor that switches lights automatically on and off is the best option.

1.2                                                  PROBLEM STATEMENT

In the last decade, home light or security light is been controlled by human being or occupant of house and this involves labour, waste time and sometime may not be switched in time or may also be forgotten which will result waste of energy. This eliminates this problem, this device was built which is used to daily and also helps to switch ON and OFF of house light daily even when the occupants are out of station.

1.3                                             OBJECTIVE OF THE PROJECT

The objective of this work is to design a device that will trigger a lamp when darkness fall on the sensor (LDR)

1.4                                                 SCOPE OF THE PROJECT

A dark activated switch 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 a battery or 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 the light when the LDR is 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 darkness 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.

1.5                                         SIGNIFICANCE OF THE PROJECT

This device is very useful in that it distinguishes daylight and dark hours. This device eliminates the need of switching the Porch lamp or Backyard lamp daily and also helps to switch ON or OFF the premises of the house when the occupants are out of station.

1.6                                           LIMITATION OF THE PROJECT

One of the problems of this device is that any opaque material can trigger the device, such as human shadow, movement of animals or ants across the sensor can trigger the system

1.7                                 APPLICATIONS OF THE PROJECT

1. Useful for automatic outdoor lighting or garden lighting at home.
2. Useful for automatic switching of street lights.

• Useful for switching the hoardings on and off automatically.

1. Useful for self-switching operation of displaying title hoardings of companies.
2. Useful as a light detector circuit when the pin of the ic is reconfigured.
3. Useful as a dark activated switch.

1.8                                         METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design of the device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out. The construction of this project includes the placing of components on Vero boards, soldering and connection of components,

• Finally, the whole device was cased and final test was carried out.

1.9                          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 dark activated alarm. In this chapter, the background, significance, objective limitation and problem of dark activated alarm were discussed.

Chapter two is on literature review of dark activated alarm. 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.