The design and construction a digital door lock system using GSM is a very important project work that can never be over emphasized, especially when it comes to a country that has security challenges. The only way you can prevent an unauthorized person from having access to your confidential property or company secret files or money kept in the bank is by implementing an activated lock system that can only be access by GSM networking. This project work can never be achieved if microcontroller is not involved. Microcontroller chip is a programmable device where all programmes as regard to the control of the activated lock is programmed. Digital door lock system using GSM has an automatic door drive that when is shutdown it cannot be open manually except by dialling the number of the sim card in the GSM modem that is connected to the microcontroller. Once the GSM phone rang once the door locks & cannot be open except the phone rings twice before it will open

CHAPTER ONE

1.0 INTRODUCTION

1.1 Background of the study

As the world of electronics tends towards the micro age, many electronics system has in recent times changed their forms of being purely discrete to the forms of hard wired and embedded. Embedded electronics simply means an electronic system that is made up of few hardware parts and much of programming that controls that entire system. The electronic systems only provide physical support to the system, while the software provides intelligence and control.

The microprocessor has been very instrumental to the development of embedded systems. Another important control of embedded systems has been the microcomputers (GSM). The microcontroller, though much newer has gained more ground in the development of embedded systems. Many important systems have been developed, among which is the microcontroller based password activated lock system with access keypad. The system has become necessary at this time when crime has remain on the ever increase, despite the efforts of the various security agents, it has equally becomes necessary to have control of access to some entrances, since it goes a long way to limit the accessibility of unauthorized persons in restricted areas.

Many organizations need to check the density of people coming into their territory, in the stadia, entrenches are check to ensure that all spectators pay before gaining access to the stadia. This also acts as a means of generating income for organizations and the governments. This seminar work is directed along the same line. It is aimed at developing a system that enables users to use only valid keys to open doors at restricted zones

1.2 Aims and Objectives of the seminar

The major objective of this work is to design and develop a microcontroller based password activated lock or save System with Access GSM CODE. This means that the work focuses on a microcontroller based design methodology as well as an improved standard of the existing security systems in most places.

1.3 SYSTEM ANALYSIS AND DESIGN

a. Specification

The design of the system made use of AT89S52 microcontroller, Hytachi LCD, 30 watt AC relay, Matrix Keypad, RL network for surge protection, Voltage and current sensitive Transformer. and a GSM

b. Sub System

1. matrix key pad for reset

2. GSM MODEM for input interface

3. AT89S52 Microcontroller as the control unit

4. Power Unit

5. LCD Interface as Output Interface

1.4 The Input Interface

The input unit consists of a GSM and gps connection. The design parameters are as shown below. It was designed using GSM code number and gps, arranged in the order of using the GSM code number to send a signal to the microcontroller in other to control the door luck and open command it also has LCD display, that display the control function of the door lock the advantage of this DIGITAL GSM DOOR LUCK, is that ;

The code was to minimize the number input lines going into the microcontroller. In this case, only 8 pins were used as against 16 pins. All rows were connected to the lower nibble of port P1 of the microcontroller. The column on the other hand were strapped to Vcc and connected to the lower nibble of port P3. This arrangement keeps the lower nibble of port P3 high always, hence acting as input of the code interface. The design of the program that controls this GSM CODE link is shown in the program design section of this report.

1.5 Determining the value of resistor used

Port P3 of the microcontroller can sink source 20mA current and applied voltage is Vcc (5Volts). From Ohm’s Law

I = V ==> R = V

R I

Therefore,

R = 5

20x10^-1

R = 250â„¦

1.6 Other Features of the Microcontroller

The other features of the microcontroller include

· Three-Level Program Lock

· 32 Programmable I/O Lines