Design And Construction Of An Electronics Letter Box Using Seven Segment Display

ABSTRACT

This work is on design and construction of an electronic letter box .This   project is developed for the users to find out whether any letter is inside the letter box and also to display the number of letters inside the letter box.

The I.C connected with the sensor counts that there is one letter inside.  When the next letter is put inside the letter box, the sensor senses the letter and the microcontroller counts two.  The same way it counts all the letters inside.

A display and ldr is connected inside the house.  The owner of the house can identify the number of letters inside the letter box. When the letter box is opened, the IC resets and the count goes to zero.

TABLE OF CONTENTS

TABLE OF CONTENT

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0      INTRODUCTION

1.1       SIGNIFICANCE OF THE PROJECT

1.2      OBJECTIVE OF THE PROJECT

1.3      ADVANTAGES OF THE PROJECT

1.4      SCOPE OF THE PROJECT

1.5      LIMITATION OF THE PROJECT

1.6      APPLICATION OF THE PROJECT

1.7      PROJECT ORGANISATION

CHAPTER TWO

2.0      LITERATURE REVIEW

2.1      HISTORITICAL BACKGROUND OF THE PROJECT

2.2      STYLES AND USAGE

2.3      FUNCTION OF MAJOR COMPONENTS USED

CHAPTER THREE

3.0      CONSTRUCTION

3.1      BLOCK DIAGRAM

3.2      CIRCUIT DIAGRAM

3.3      SYSTEM OPERATION

3.4      CIRCUIT DESCRIPTION

3.5      CIRCUIT PARTS

3.6       DESCRIPTION OF COMPONENTS USED

3.7      POWER SUPPLY UNIT

CHAPTER FOUR

4.0      RESULT ANALYSIS

4.1      CONSTRUCTION PROCEDURE AND TESTING

4.2      CASING AND PACKAGING

4.3      ASSEMBLING OF SECTIONS

4.4      TESTING OF SYSTEM OPERATION

4.5      INSTALLATION OF THE COMPLETED DESIGN

4.6      COST ANALYSIS

CHAPTER FIVE

5.0      CONCLUSION

5.1      RECOMMENDATION

5.2      BIBLIOGRAPHY

CHAPTER ONE

1.1                                                        INTRODUCTION

A letter box, letterbox, letter plate, letter hole, deed, mail slot, or mailbox is a receptacle for receiving incoming mail at a private residence or business. For the opposite purpose of collating outgoing mail, a post box is generally used instead.

Letterboxes or mailboxes consist of four primary designs:

• A slot in a wall or door through which mail is delivered (through-door delivery)
• A box attached directly to the house (door-to-door delivery)
• A box mounted at or near the street (curbside delivery)
• A centralised mail delivery station consisting of individual mailboxes for an entire building
• A centralised mail delivery station consisting of individual mailboxes for multiple recipients at multiple addresses in a particular neighborhood or community
• An electronics circuit

The electronic letter box is a very useful gadget for homes and offices the circuit uses single Monolithic -555 in dual in line plastic package and a few external components. The main advantage of the letter box is we can find out the presence and absence of letter inside the box without opening the box.

In this system, When letter drop by someone into the letter box then the seven segment attached at the output start counting which indicates that there is a letter in your letter box. To identify the presence of a letter in the box we have connected a LDR as well as source of light. LDR is a special kind of resistor whose action based on the intensity of light declining on it. In the time of total darkness LDR resistance is approx 1 mega ohm while at the time of bright light its resistance is 2-5 ohm. In this circuit the light source is adjusted with the LDR in such a way that the light will directly drop on the LDR so that when any letter comes inside the letter box it will chunk the light beam and LDR will be beneath darkness.

1.2                                         SIGNIFICANCE OF THE PROJECT

This project is very useful in institutions; house etc to identify the letters inside the letter box.

1.3                                             OBJECTIVE OF THE PROJECT

The objective of the project is to design a device that When letter drop by someone into the letter box then the Seven segment attached at the output start counting which indicates that there is a letter in your letter box.

1.4                                 ADVANTAGES ELECTRONIC LETTER BOX

Advantage of the letter box is we can find out the presence and absence of letter inside the box without opening the box. Here light depending resistor (LDR) is used as a sensor to detect the presence of letter. Thus this circuit solves the problem of going again and again to the gate of the house to check-up whether a letter is there in the box or not. WORKING To detect the present of letter, we have used LDR and a source of light.

The L.D.R, most important part of this circuit, is a special type of resistance whose value depends on the brightness of the light which is falling on it.
It has a resistance of about 1 mega ohms when in total darkness, but a resistance of only about 2-5 k ohms when brightly illuminated.

The resistance of L.D.R. is minimum when the light falling on is maximum and vice versa when the light falling is minimum. The source of light and LDR is so adjusted in the letter box, that the light will directly fall on the LDR. When a letter is kept inside, it will block the beam of light and LDR will be under darkness.

1.5                                                 SCOPE OF THE PROJECT

When anyone drops a letter in your letter box, then this circuit will produce a visual alarm. LM555 timer, CD4033 and as well as LDR are the basic building block of the circuit. The voltage that is generated at the output of the 555 timer is hundreds of thousands times more than the difference of voltage between the input points.

1.6                                           LIMITATION OF THE PROJECT

• This device can experience false triggering whenever any other opaque material is drop inside the box.
• It will stop working whenever mains supply fails.

1.7                                            APPLICTION OF THE PROJECT

This device can be used in the following places:

1. Homes
2. Churches/mosque
3. Garage
4. Offices, or any other public place

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 electronic letter box. In this chapter, the background, significance, objective limitation and problem of electronic letter box were discussed.

Chapter two is on literature review of electronic letter box. 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.