Design And Construction Of A Door Alarm System

The door alarm system is an electronic device that can be used as a security device. It is an electronic watch dog, because when installed to a door, and somebody touches the door, it sounds an alarm. The unit is built from discrete semi conductor device. It is relatively simple in both its operation and analysis. One particular feature of this project circuit (the door alarm system) is its versatility. The circuit can be adapted for other applications. All the Information necessary for its realization is contained in this project write-up. Chapter one contains the introduction to the door alarm system, Chapter two contains the circuit analysis and component review, Chapter three contains the research and methodology adopted, Chapter four contains the design and construction while the work was concluded with Chapter five.

TABLE OF CONTENT
Title Page
Certification – – – – – – – – i
Dedication – – – – – – – – – ii
Acknowledgement – – – – – – – iii
Abstract – – – – – – – – – iv
Table of content – – – – – – – – v

CHAPTER ONE
1.1  Introduction
1.1  Background of the study

1.2     problem statement
1.3     Objective of the project
1.4     Purpose of the project

1.5     significance of the project
1.6     Application of the project

1.7     scope of the project

1.8     methodology

1.9     project organisation

CHAPTER TWO
2.1 LITERATURE REVIEW – – – – – – 5
2.2 door alarm System – – – – – – 5
2.3 Types of  touch activated alarm System – – – – 5
2.4 The D.C. Power Supply Unit – – – – 6
2.5 The Touch Point Unit – – – – – – 7
2.6 The Monostable Multivibrator Unit – – – 8
2.7 The Transistor Switching Unit – – – – 9
2.8 The Load Power Control Unit – – – – 11
2.9 The Alarm Sounder Unit – – – – – 12
2.10 Component Review – – – – – – 13
2.10.1 Transformer – – – – – – – 14
2.10.2 Diode – – – — – – – – 16
2.10.3 Capacitor – – – — – – – 17
2.10.4 Resistor – – – – – – – – 21
2.10.5 Silicon Controlled Rectifier – – – – – 23
2.10.6 555Timer IC – – – – – – – 25
2.10.7 Transistor – – – – – – – 30
2.10.8 Switch – – – – – – – – 33
2.10.9 Piezo Buzzer – – – – – – – 33

CHAPTER THREE
3.1 RESEARCH / METHODOLOGY – – – – 35
3.2 Design Philosophy – – – – – – 35
3.3 Design Approach – – – – – – – 35
3.4 Design Procedure- – – – – – – 36
3.5 Circuit Principle of Operation – – – – 38

CHAPTER FOUR
4.1 DESIGN AND CONSTRUCTION – – – – 40
4.1.1 Selection of the Transformer – – – – 40
4.1.2 Selection of the Diodes – – – – – 40
4.1.3 Selection of the Capacitor – – – – – 41
4.2 Design of the Power Supply Unit – – – – 42
4.3 Design of the Monostable Multivibrator – – – 42
4.4 Design of the Switching Unit – – – – 43
4.5 Design of the Load Power Control Unit – – – 45
4.6 Design of the Alarm Sounder Unit – – – 45
4.7 Construction of the Project – – – – – 46
4.7.1 Construction of the Main Electronic Circuit – – 46
4.7.2 Construction of the Casing – – – – – 47
4.3 Testing and Result – – – – – – 47
4.4 Bill of Engineering Measurement and Evaluation – 48
4.4.1 Cost Analysis – – – – – – – 48

CHAPTER FIVE
5.1 Conclusion – – – – – – – – 50
5.2 Recommendation – – – – – – – 50
5.3 References – – – – – – – – 51

CHAPTER ONE

1.0                                          INTRODUCTION

The door alarm system is an electronic system that gives an audible alarm when the door knob it is connected to, is touched. If the door is the metal type then it will sound an alarm whenever any part of the door is touched. For the wooden door, the door alarm system is connected to the door handle, and hence, sounds an alarm only when the door handle is touched. The door alarm system is represented by a block diagram below. It consists of a d. c. power supply unit, touch point, monostable multivibrator unit, latching unit, electronic switching unit and the alarm sounder unit.

1.1                         BACKGROUND OF THE PROJECT

Since the 1950’s there has been a great upsurge in the development, production and applications of semi conductor devices. Today there are well over 100 million semi-conductor devices manufactured in a year. These figures alone indicate how important semi-conductor devices have become to man both for home and industrial applications. In fact, the present day advancement in technology is largely attributed to the widespread use of semi-conductor devices in the commercial and industrial fields. One major field of application of semi-conductor devices in the recent years has been in security systems. These security systems are electronic systems used as deterrent to intruders, burglars, thieves and unauthorized person in a place or places where they are installed. They alert the installer of the presence of the above mentioned persons. One can be alerted by means of audible alarm, siren, bell, e.t.c. or by visual means. One example of such security system is the door alarm system which is the focus of this project work.

1.2                                                  PROBLEM STATEMENT

The need for having a constant 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. This device brought solution to this need. It ensures adequate protection against intruders.

1.3                                OBJECTIVE OF THE PROJECT

The objective is to construction an electronic circuit that acts as a watch dog. It is used to protect a door when it is on; it sounds an alarm when the door is touched. The door alarm system is an electronic system because it consists of two or more circuit units of different functions working together to achieve a desired performance or goal.

1.4                                 PURPOSE OF THE PROJECT

The door alarm system circuit was designed to the sound on alarm when the touch point is touched by a human being making contact with the earth.

1.5                                 APPLICATION OF THE DEVICE

The door alarm system finds application in the following arrears;

1. It can be used as a bugler alarm.
2. It can be used as an intruder alarm.
3. It can be modify for use as a tap door bell

1.6                                  SCOPE OF THE PROJECT

system designed to detect intrusion – unauthorized entry – into a building or other area such as a home or school. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders. This Touch Alarm Circuit is constructed by using timer IC 555 and few easily available components. This circuit will give alert sound when some one touch the door knob, It is suitable for simple security applications. To implement this circuit your door knob must be a conducting material.

1.7                                         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.

1.8                                                         PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.