A Microprocessor Controlled Door Security System
Undergraduate Reserch Project 2005/2006: FSC32P2
Faculty of Science
University of Ruhuna
Matara 81000, Sri Lanka.

No part of this document may be copied/stored in any of the printed or electronic
versions/devices without permission from the author of this document and the inventor
of the device which is described in this document.

Author/Inventor:
S.S. Abeywickrama.
“Isula”
Nayadola,
Alapaladeniya.
0713052524
Abeywickramass@yahoo.com

INTRODUCTION

It seems that there is an increasing demand for security systems for houses and vehicles. Conventional Mechanical locks are being replaced by electronic security systems because of the shortcomings of the former. Although this is used for vehicles it cannot be seen using in houses often. While there is a radio waves transmitter and a receiver in above mentioned security systems, the security system unlocks when the relevant frequency is given by the transmitter, but the shortcoming in this system is that the system can be unlocked by giving the above frequency through unauthorized devices, and also such security systems are very expensive. In case of these drawbacks the necessity of less power consuming, more effective and less expensive security systems, is increasing day by day.

The system that I am introducing here is an electronic security system with a password protection, which is more secure than a frequency controlled system. The number of times allowed to enter a password is limited to four. In addition this system can be customized according to the user needs. Also, this system can be used with current security systems in homes and vehicles. This system is more reliable, sensitive and intelligent because of the latest microcontroller technology is used and also low power consuming and cost effective.

This system contains mainly an interfacing device as shown in Fig. 1. The figure shows how the system looks from the outside. It provides the communication ability between the system and user. User can permanently fix this device on their doors or vehicles’ dash board .The security system interface which is only view of the out side world.

This button provides system power management (if this button is off then always system is locked, it can be unlock by keeping this button is turning on and entering correct password.

These buttons operate all main functions of this system. To verify the password which is entered by using white buttons, should press “Enter” function button. If you feel that password which entered before press “Enter” button is incorrect you can clear it by using “CLEAR” function button. The current password can be changed by using “CHANGE” Button

It’s generating “beep” tone. That can hear at system startup and button pressing acknowledgement.

This L.E.D is on during the normal startup, key pressing. And in some Special massages.

“ERROR” L.E.D. is lit up at incorrect password and end of the password entering period (only vehicle)

This system made by two parts, which are hard ware and software. Micro controller, keyboard, L.E.D.s , etc. are hardware and the Software is stored in the flash memory and EEPROM of the micro controller. The software controls all hardware components and security mechanism.

This circuit can be applied in a house as well as in a vehicle. Here a solenoid should be used for the output end to operate a key for the house while a relay should be used in vehicles instead. When the door closes, the security system is set automatically. If one wants to unlock the door the power should be on and the correct password should be given. This circuit consumes electricity only for unlocking the security system.