The main objective of this project was to ensure a proper security to car being parked in garage against theft or an intruder. The circuit uses three NE555 timers; one of the NE555 was wired as a monostable oscillator and remaining two were wired as tone generator and amplified to obtain a maximum audible sound. However, pin 2 of the first NE555 was used as sensor part .When pin 2 has contact with human body or hand it will activate the IC1 which will also bias transistor and this transistor was wired in a way that once it is powered it will close circuit thereby passing a negative supply voltage to tone generator circuit and outputted out through a loud speaker or buzzer.

This device functions as a major security device against car-theft as stated above. It is an electronic device that is connected to the battery of the car it is being installed in and gets activated when the car engine is switched off and the car stationed at a place. The device is not seen but, it has an indicator light which shows that the alarm has been activated. When the body of the car is touched by human hand, it sends a negative signal to the device which needs a negative pulse to get activated; it sends this negative from the human hand to the tone generator IC which triggers the alarm.

TABLE OF CONTENT

Title Page ...…………………………………………………………………….i

Certification…………………………………………………………………….ii

Dedication ……………………………………………………………………...iii

Acknowledgement …………………………………………………………….. iv

Abstract ………………………………………………………………………….v

Table of content ………………………………………………………………...vi

List of Symbols ………………………………………………………………. vii

CHAPTER ONE: Introduction 1.1 Background of study…………………………………………………… 1

1.2 Aims and objectives…………………………………………………… 3

CHAPTER TWO: Literature Review……………………………………….4

CHAPTER THREE: Specification and operation of system component 3.1 Description of NE55 Timer…………………………………………….12

3.2 Description of Resistor………………………………………………. 14

3.3 Description of Capacitor…………………………………………….. 16

3.4 Description of Diode………………………………………………… 27

3.5 Description of Transformer …………………………………………… 32

3.6 Description of Loud Speaker and Buzzer……………………………… 41

3.7 Description of Transistor………………………………………………. 43

3. 8 Description of L.E.D………………………………………………….. 47

CHAPTER FOUR: Operation of system and its circuit and block diagram

4.1 Operation of circuit ………………………………………………… …55

4.2 The circuit diagram………………………………………………….. ..57

4.3 The block diagram………………………………………………………58

CHAPTER FIVE: Construction, Testing and Packaging

5.1 Values of components………………………………………………….59

5.2 Assembly………………………………………………………………60

5.3 A schematic diagram of the finished work…………………………….63

CHAPTER SIX: Conclusion and Recommendation

6.1 Conclusion ………………………………………………………….. .64

6.2 Recommendation …………………………………. …. ……… .….65

6.3 Observations ………………………………………………………..66

6.4 Dificulties…………………………………………………….. …57

6.5 References…………………………………………………. …………68

LIST OF SYMBOLS

NAME SYMBOLS

Resistor

Transistor

Diode

Zener diode

Trimmer capacitor

Polarized capacitor electrolytic capacitor symbol

Unpolarized capacitor capacitor symbol

Variable capacitor

CHAPTER ONE: INTRODUCTION

1.1. Background of the Study

The first car alarm was a primitive contraption that utilized a bell or horn connected to the drive shaft. It was created by an unnamed Nebraska inventor in June 20^th, 1920. It utilizes the drive shaft to operate its own bell or horn signal when the car is properly moved. This is just a little talk on a car alarm but not a car touch intruder alarm which is a modern, more advanced, and more reliable type of car alarm.

This car touch sensitive alarm project consist of three NE555 timer IC, the first NE555 was wired as monostable multi-vibrator and the remaining two were wired as tone generator. When the sensor is touch or has contact with human hand perhaps body, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of R4 (10M) and Q1 (transistor) was bias via R3 and this transistor is in such a way that once it was biased it will supply a negative voltage to tone generator thereby making two NE555 timer which was know as (tone generator) to oscillate to make a bell sound through the buzzer. The tone generators are configured as an astable multi-vibrator whose oscillation frequency can be varied with the help of PR1 and PR2. By adjusting the values of PR1 and PR2, modifications on the tone are possible.

The reset button is used to set or open circuit the system back to its initial stage. The system is powered with 12V power supply voltage.

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 specification and operation of system component. Chapter four is operation of system. Chapter five is about construction, testing and packaging. Chapter six is conclusion, observation, 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 vehicle owners or users when their vehicles are parked or stationed anywhere without much fear of car-theft.