This presentation summarizes a student project that developed a digital door lock system and automatic room light controlling system using a microcontroller. The system uses an AT89S52 microcontroller to control a keypad lock on a door and infrared sensors to detect movement and automatically turn lights on and off. The presentation describes the existing manual systems, components used, circuit designs, applications, and plans to add voice password and control additional devices like fans.

1. Welcome To Our Presentation
Bangladesh University of Business and
Technology
(BUBT)

2. Digital Door Lock and Room light controlling
System
Name ID
Md. Mahfuzur Rahman 14153103024
Md. Sayeed Mahmud 14153103095
Marufa Akter Mukty 14153103105
Md. Sabbir Alam 14153103110
Tanjila Akther 14153103121
Ajmoon Nahar Urmi 14153103132
Supervised By:
Md. Maynul Islam
Lecturer in EEE
Department of EEE

3. Content
 Introduction
 Existing System
 Aim of the Project
 Block Diagram
 Components Required
 Component Description
 Proteus Circuit Design of Our Project
 Circuit Description
 Hardware Circuit of Project
 Working of the project
 Applications
 Future Plan

4. Introduction
Security is a major concern in our day to day life, and digital locks have become an important part of these
security systems. Automatic Room Light controlling System is a microcontroller based project that automatically
turn on or off the lights in a room. Electricity, being one of the most important resources, must be utilized
carefully

5. Existing System
 Manual door lock system
 For opening the door use the key system.
 Low security system.
 We often forget to switch off lights or fans when we leave a room. By using this
system, we can intentionally forget about the lights as the system will automatically
take care of them.

6. Aim of the Project
 Electronic code lock using AT89S52 Microcontroller, which can only be unlocked by a
predefined code, if we enter the wrong code, the system alerts by siren the buzzer.
 The project can also make high security.
 The aim of this project is to automatically turn on or off the lights in a room by
detecting the human movement. We implemented this project using 8051
Microcontroller and two Infrared (IR) sensors.

7. Block Diagram Lock Door

8. Working Explanation
This system mainly contains AT89S52 microcontroller, keypad module, buzzer and LCD.
At89s52 microcontroller controls the complete processes like taking password form
keypad module, comparing passwords predefined password, driving buzzer and send status
to LCD display. Keypad is used for inserting password into the microcontroller. Buzzer is
used for indication of wrong password and LCD is used for displaying status or messages
on it. Buzzer has inbuilt driver by using a NPN transistor.

9. Components Required
 8051 Microcontroller (AT89S52)
 4X4 Keypad Module
 Buzzer
 16x2 LCD
 Resistor (1k,10k)
 Network resistor (10K)
 Capacitor(10uf)
 Red led
 IC 7805
 Development Board
 2 x Infrared Sensors
 5V Relay Module
 Lamp
 11.0592 MHz Crystal
 Power Supply
 Connecting wires

10. Component Description
4X4 Keypad Matrix
 In this circuit we have used multiplexing technique to interface keypad to the 8051 microcontroller, for
entering the password in the system. Here we are using a 4x4 keypad which has 16 keys
 If we want to use 16 keys then we need 16 pin for connection to 89s52, but in multiplexing technique we
need to use only 8 pins for interfacing 16 keys

11. 4X4 Keypad Matrix
 Multiplexing technique is a very efficient way to
reduce number of pins used with the
microcontroller for providing the input or password.
Basically this technique is used in two ways - one
is row scanning and other one is column scanning.

12. LCD Display Module
LCD (liquid crystal
display) LCD is the
technology used
for displays in notebook and
other smaller computers. Like
light-emitting diode (LED)
and gas-plasma technologies,
LCDs allow displays to be
much thinner than cathode ray
tube (CRT) technology

13. AT89S52 Microcontroller
The AT89S52 is a low-power,
high-performance CMOS 8-
bit microcontroller with 8K
bytes of in-system programmable
Flash memory. The device is
manufactured using Atmel's high-
density nonvolatile memory
technology and is compatible
with the indus- try-standard
80C51 instruction set and pinout.

14. IR Sensor Module
 An Infrared or IR Sensor is a simple
circuit that is used to detect objects
(Proximity Sensor) or measure
distance (Range Finder). An IR Sensor
consists of 3 components: an IR
Transmitter (IR LED), an IR Receiver
(like a Photo Diode) and a signal
processing circuit.
 We have used reflective type IR sensor
modules in this project. The detailed
circuit diagram of the module is shown
in the following image.

15. 5V Relay Module
A 5V Relay Module is used in this project
which helps 8051 Microcontroller to
operate high voltage AC loads like a light.
The detailed circuit of the Relay Module is
shown in the following image. It consists
of a 5V Electromechanical Relay, an
Optocoupler IC, transistor, two resistors
and two diodes.

16. Proteus Circuit Design of Our Project

17. Proteus Circuit Design for Room light
controlling

18. Circuit Description
Circuit diagram for this Digital lock using 8051 has been shown below and can easily be
understood. Keypad module’s Column pins are directly connected to pin P0.0, P0.1, P0.2,
P0.3 and Row pins are connected to P0.4, P0.5, P0.6, P0.7 of 89s52 microcontroller’s port
0. A 16x2 LCD is connected with 89s52 microcontroller in 4-bit mode. Control pin RS,
RW and En are directly connected to pin P1.0, GND and P1.2. And data pin D4-D7 is
connected to pins P1.4, P1.5, P1.6 and P1.7 of 89s52. And one buzzer is connected at pin
P2.6 through a resistor

19. Hardware Circuit of Project

20. Hardware Circuit of Project
We have used a predefined password in the program, this
password can be defined by the user in the code below.
When user enters a password to the system, then system
compares the user entered password with stored or
predefined password in Code of Program. If a match occurs
then LCD will show “Access Grated” and if the
password doesn’t match then LCD will show “Access
Denied” and buzzer will continuously beep for some time.
Here we have
used string.h library. By using this library we can compare or
match two strings, by using “strncmp” function.

21. Hardware Circuit of Project
 In this project, an automatic room lighting system is developed using 8051
microcontroller. The working of the project is explained here.
 The main component of the project is IR Sensor and we have used two of them. The
placement of the sensors is important as it will determine the functioning of the project.
 Practically speaking, both the sensors must be placed on the either side of the door or
entrance of the room. The sensor placed on the outside of the room is named as Sensor
1 and the sensor, which is placed on the inside is named Sensor 2.
 When a person tries to enter the room, Sensor 1 detects the person first and then Sensor
2. This action will indicate the 8051 Microcontroller that the person is entering the
room.

22. Applications
 Digital Password door Controlling system with password , it can be used to turn on the
door in a room when a person enters the room and turn it off when the person leaves
the room.
 The project can also secure for any low security
 The project can be modified with LEDs and as the access password in the room door
and also we enter the wrong code, the system alerts by siren the buzzer.

23. Applications
 Automatic Room Light Controlling with Bidirectional Visitor Counter can be used to
automatically turn on the light in a room when a person enters the room and turn it off
when the person leaves the room.
 The project can also be dubbed as a Bidirectional Visitor Counter it is an integral part
of the Automatic Room Lighting circuit.
 The project can be modified with LEDs and as the number of persons in the room
increases, the number of LEDs turning ON also increases.

24. Future Plan
 In future using the idea make digital password door controlling system with voice
password , it can be used to turn on the door in a room when a person enters the room
and turn it off when the person leaves the room.
 The project can also make high security.
 The project can be modified with LEDs and as the access artificial intelligence voice
password in the room door and also we enter the wrong code voice, the system alerts
by siren the buzzer.

25. Future Plan
 Automatic Room Light and Fan or AC(Air Condition)Controlling with Bidirectional
Visitor Counter can be used to automatically turn on the light in a room when a person
enters the room and turn it off when the person leaves the room.
 The project can also be dubbed as a Bidirectional Visitor Counter it is an integral part
of the Automatic Room Lighting circuit.