Report (Electromagnetic Password Door Lock System)

ATEL3002 MINI PROJECT

Chapter 1 Introduction

1.1 Background

Today, we are living in the in the of embedded systems surrounded by devices that

based on the embedded systems like cars, washing machine microwave-oven,

medical equipment's etc.

An embedded system is a computer system designed for specific control functions

often with real time computing constraints. It is embedded as part of a complete

device which often including hardware and mechanical parts. By contrast, a

general-purpose computer, such as a personal computer (PC), is designed to be

flexible to meet a wide range of end user needs. It controls many devices in

common use today.

One of prominent example of an embedded system is a microcontroller, which is a

small and tiny computer designated to perform some specific tasks. A

Microcontroller program (firmware) is the one, which decides what functionality

the microcontroller provides to a user. A program that has the ability to run on a

microcontroller without the need of an operating system is called as a firmware.

That means, a firmware has the privilege to access the hardware directly. This

paper tries to explain an electronic lock firmware in detail. The basic idea of

microcontroller is to collect all the input and output peripherals in one simple

circuit, which represent the microcontroller instead of the large and sophisticated

computer with microprocessor and large numbers of peripherals. The firmware

directly deals with peripherals and Input / Output ports to give complete

functionality of microcontroller.

1.2 Problem Definition

Nowadays, the digital door lock system is available at anywhere, but not all the

people can afford to buy it. This is because the price for this system is quite

expensive and not all people willing to spend lots of money to purchase this

system. They are much to purchase traditional door lock which is cheaper and

easier to use than digital door lock. While these traditional devices have their

limitations too, one of the major problems is people easily forget where’s the

location of the key actually put. They have to waste their time as they have to find

the key for door lock whole day to switch on the door. This is mainly happen on the

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person who is having a bad memory. Therefore, they have to make lots of duplicate

key for backup usage and this may cause wastage of money too.

1.3 Project aims

Based on the problem stated above, my proposed system can easily solve of this

problems. My project aims to minimise the problem of forgetful person that he or

she just only needed to memorise the default password for digital door lock. And

digital door lock is much reliable and efficient than traditional ones as it offer

higher security level. This is because the only owner knows his/her default

password while other intruders do not know the password is. And also, my

proposed system is using with low cost but high quality of component such as

microcontroller which is main “brain” of the system and 16x2 LCD which is

display the message to user.

1.4 Project Objectives

i) To provide a security lock that is efficient and reliable, at cheaper price in

comparison with traditional devices.

ii) To provide opportunity of textual displays as compared to conventional

ones which only show digits.

1.5 Project Outline

As I proposed the mini project, I will update my schedule and progress to my

supervisor, Mr Tai See Chew for future progress and outline. He gives me some

advice and recommendation to improve my proposed mini project. After finish my

mini project, I write this report about the progress and how I develop and

troubleshoot my mini project. Below is the schedule how my mini project is being

organised:

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Progress achieved \ Week 1 2 3 4 5 6 7 8 9 10 11 12 13 14Project specification. √Proposal write-up and submission. √ √Construct minimal circuitry for microcontroller circuitry and verify operation

√ √

Develop interfacing circuitry for 2x16 LCD and verify operation

√

Develop interfacing circuitry for 4x4 Keypad

√

Develop interfacing circuitry for power supply for whole circuit

√

Develop an application for locking door mechanism

√ √

System integration, characterizing, testing & verification.

√ √ √ √ √

Prototype fabrication √ √ √Report write-up √ √ √ √ √ √ √Report submission √Presentation √

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Chapter 2 Design and Implementation

In the construction of this project, the modular design is employed, the project is divided

into two parts namely hardware and software with each of the section analysed extensively.

The block diagram of the microcontroller based electronic door lock is shown below:

The construction of this project employs majorly the PIC16F877A microcontroller for

several reasons. Firstly, it is operated on a +5V DC supply and draws very little current.

Furthermore, it has a very low power dissipation and high speed of operation. For this

project, I had separated it into 5 parts which is

i) POWER SUPPLY unit,

ii) MICROCONTROLLER PIC16F877A unit,

iii) LCD unit,

iv) LED BUZZER RELAY unit and

v) 4x3 KEYPAD unit,

Therefore, I can easily make my troubleshooting when the project is malfunction at certain

part. For examples, if the buzzer no sound on, I will check and troubleshoot the problem on

LED BUZZER RELAY unit and MICROCONTROLLER PIC16F877A unit. For my mini

project, I used Eagle 6.40 to design the schematic diagram and also PCB diagram.

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Figure 2.1 Block Diagram for Password Door Lock System

4X4 Keypad

PIC 16F877A

Buzzer

Relay

LCD

Door Lock


2.1 Hardware Design

2.1.1 Schematic Diagram and Description

POWER SUPPLY UNIT

This project utilizes DC voltages at two specified levels; +5V to supply the microcontroller

and +12V to activate the normally-open relay to be close so that the electromagnet will be

turn off for few seconds. The power supply unit consists of diode 1N4007, voltage

regulators, electrolytic capacitors, multilayer capacitors, LED and resistor. The figure

below shown the circuit diagram of power supply unit

Higher input voltage will produce more heat at LM7812 and LM7805 voltage

regulator. Anyhow, LM7805will still generate some heat at 12V. There is only one type of

power connector for the circuit, which is JP1. The JP2 and JP3 is the +5V voltage which is

connected to MICROCONTROLLER PIC16F877A unit and LCD unit after regulate from

LM 7805 voltage regulator while the JP4 is the +12V voltage which is connected to

LEDBUZZERRELAY unit for the purpose of activation of normally-off relay.

As shown in Figure 2.2, the D1 and D2 (1N4007) is use to protect the circuit from

wrong polarity supply. C1 and C2 is use to stabilize the voltage at the input side of the

LM7812 voltage regulator, while the C3 and C4 is use to stabilize the voltage at the output

side of the LM7812 voltage supply or input side of LM7805 voltage regulator. Finally C5

and C6 is use to stabilize the output side of LM7805 voltage supply. The actual purpose of

both multilayer and electrolytic capacitors is to filter out the noise and voltage variations

from the input source. LED1 is yellow LED to indicate the power status of the circuit, and

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Figure 2.2 Schematic diagram of POWER SUPPLY unit


the R1 is 0.25W 5% (220R) resistor to protect the LED1 from over current that may burn

the yellow LED.

MICROCONTROLLER PIC16F877A unit

As shown the figure above, the microcontroller that I used for this project is PIC16F877A.

This controller is widely used for experimental and modern applications because of its low

price, wide range of applications, high quality, and ease of availability. Therefore, it can

support up to 368×8bit of RAM (data memory), 256×8 of EEPROM (data memory), 8k×14

of flash memory. It is ideal for applications such as machine control applications,

measurement devices, study purpose, and so on. Besides, PIC16F877 has 5 basic

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Figure 2.3 Schematic diagram of MICROCONTROLLER PIC16F877A unit


input/output ports. They are usually denoted by PORT A (R A), PORT B (RB), PORT C

(RC), PORT D (RD), and PORT E (RE). These ports are used for input/ output interfacing.

In this controller, “PORT A” is only 6 bits wide (RA0 to RA7), ”PORT B” , “PORT

C”,”PORT D” are only 8 bits wide (RB0 to RB7,RC0 to RC7,RD0 to RD7), ”PORT E”

has only 3 bit wide (RE0 to RE2).

All these ports are bi-directional. The direction of the port is controlled by using TRIS(X)

registers (TRIS A used to set the direction of PORT-A, TRIS B used to set the direction for

PORT-B, etc.). I set RA0-RA5 and RE0-RE1 as the pin for the purpose of detecting the

number of 4x3KEYPAD pressed. Pin 15 to pin 22 (RC0-RC3 & RD0-RD3) and pin 27 to

pin 30 (RD4-RD7) are set as output pin for displaying message on the 16x2 LCD. While

RC2-RC3 and RB1-RB2 are also set as output for LED BUZZER RELAY unit.

One I/O pin is needed for one push button as input of PIC microcontroller. The connection

of the push button to the I/O pin is shown in Figure 2.4. The I/O pin should be pull up to

5V using a resistor (with value range 1K-10K) and this configuration will result an active-

low input. When the button is being pressed, reading of I/O pin will be in logic 0, while

when the button is not pressed, reading of that I/O pin will be logic 1. When the reading of

I/O pin is in logic 0, this means that the whole system will be reset and start again.

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Figure 2.4 Push Button as input for PIC


LCD unit

Figure 2.5 is a 2X16 character LCD. LCD connection pins and function of each pin are

shown in table below:Pin Name Pin Function Connection

1 VSS Ground GND

2 VCC Positive supply for LCD VCC

3 VEE Brightness adjust CONT

4 RS Select register, instruction or data register RS

5 R/W Select read or write GND

6 E Start data read or write E

7 DB0 Data pin bus DB0








15 LED+ Backlight positive input VCC

16 LED- Backlight negative input GND

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Figure 2.5 Schematic diagram of LCD unit


LED BUZZER RELAY unit

One I/O pin is needed for one LED as output of PIC microcontroller. The connection for a

LED to I/O pin is shown in the schematic above. The function of R1 and R2 is to protect

the LED from over current that will burn the red and green light LED. When the output is

in logic 1, the LED will ON, while the output is in logic 0, the LED will OFF. The relay

used for the project consists of 8 pins, 2 pins is the 2 end of the coil, 2 is COM, 2 is NO

and 2 is NC that shown in Figure 2.6

One end of the coil is connected to 12V and another end is connected to an NPN transistor

(2N2222) to amplify the small IC current to larger value required for the relay coil. COM

pin is connected to 12V and NO is connected to a 2510 2-pin connector which is provided

to locate the door magnetic lock. Buzzer can be connected to any I/O pin of

microcontroller PIC16F877A as output.

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Figure 2.5 Schematic diagram of LED BUZZER RELAY unit

Figure 2.6 Illustration of GoodSky DC 12V Relay


4x3 KEYPAD unit

Keypad is an array of switch. There will be 2 wires connected each time a button is

pressed.

For example; when button ‘1’ is pressed, R1 and R5 is connected. There is no connection

between rows and also columns. The button makes it connect together. In this project, the

keypad consists of 7 pins. The 7 pins remaining are separated into 2 groups, 4 pins (C1-C3)

connect to input and 4 pins (R1-R4) connect to the output. Input must be pull high to 5V

using a resistor and this configuration will result an active-low input.

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Figure 2.7 Schematic diagram of 4x3 KEYPAD unit


2.1.2 PCB Diagram and Design

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Figure 2.9 PCB diagram of MICROCONTROLLER PIC16F877A unit

(top view)

Figure 2.8 PCB diagram of POWER SUPPLY unit (top view)


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Figure 2.10 PCB diagram of LED BUZZER RELAY unit (top view)

Figure 2.11 PCB diagram of LCD unit (top view)


2.2 Software Design

The software is designed in order to support the effectiveness of the hardware device. The

complex and intricate operating routine of the software is achieved by writing the program

in modules starting with the program algorithm, followed by the program flowchart shown

in Figure 2.18. The software was written in C language, and was written in sections for

easy debugging and troubleshooting. Each section is tailored to meet the duty that will be

imposed on the corresponding hardware unit.

Configuration of program

Figure 2.12 shows the configuration of the program and the

initial value for certain variables and port pins. The

ADCON1 register is configured with the binary value of

‘00000110’ to change the entire port A pins into digital I/O

instead of analog I/O. All the port A/B/C/D&E are bi-

directional port meaning that they can be input or output.

The corresponding data direction register are

TRISA/B/C/D&E. Setting a TRIS bit (=1) will let the

corresponding port bit an input. Clearing a TRIS bit (=0)

will let the corresponding port bit an output. For an example,

refer to the source code in Figure 1, TRISA is given the

value ‘11001111’ in binary. This means port A pin 4&5 are

output while the rest are inputs.

Configuration of LCD

The configuration of the LCD is shown in Figure

2.13.

Any words can be sent and displayed by using the

LCD function (refer to sample program).

‘lcd_goto’ function decides from which column

the string start.

Scanning of Keypad

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Figure 2.12

Figure 2.13


Coding in Figure 2.14 shows a simple method to read the keypad. Program will scan row

and column of keypad to read 4 digit password entered by user (Refer Figure 2.15 and

Figure 2.16). First, clear the output pin RE1 and set the others. Go to a ‘scancolumn1’

function shown in Figure 2.16. If the RA0 (input) detect a 0, it means the ‘1’ key is pressed

(please refer to the general description of keypad). Now, clear the second column which is

pin RE0 and set the others. Go to ‘scancolumn2’ function to scan whether the key ‘4’, ‘5’,

or ‘6’ is being pressed. If RA1 (input pin) detects a 0, meaning that the key ‘5’ is pressed.

Clear RA5 and set the others and go for ‘scancolumn3’ function to detect the key ‘7’, ‘8’,

or ‘9’. At last, clear RA4 and go for ‘scancolumn4’ function.

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Figure 2.14


Refer to the scancolumn1 function in Figure 2.16, if RA0 pin equal to ‘0’ (‘1’ key is

pressed), the program under the “if” command will be activated. First, the “while”

command will wait the ‘1’ to be released to make sure the program under the “if”

command will only run one time for a press. After that, the words on LCD screen will be

cleared if the ‘password_count’ variable is equal to zero. The purpose of the

‘password_count’ variable is to let the LCD screen clear when the first digit is entered. The

LCD will display the symbol ‘*’ to tell user that the first digit is already been entered.

Next, ‘1’ value is stall at the keyin_char array. After that, password_count will increase 1

for 1 digit entered. Program will continue the process until password_count variable is

equal to 4 or 4 digit password has been entered by user.

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Figure 2.15 Figure 2.16


Comparing result

After all 4 digits have been entered, program will compare value in keyin_char array with

value in stalled_char array. Look at Figure 2.17, after the ‘password_count’ variable count

to 4, the program will compare value in keyin_char array with value in stalled_char array.

If value in keyin_char array is same with value in stalled_char array, LCD will display

‘Accessed’, ‘led_green’ will ON, buzzer will beep once and relay will activated. If value in

keyin_char array is different with value in stalled_char array, LCD will display ‘Denied’,

‘led_red’ will ON and buzzer will beep twice.

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Figure 2.17


Figure 2.18 Flow chart of overall system

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Scanning Process.Enter 4-digit password.

Yes No

Yes No

Compare key in value with stall value

1st Key In value

==1st Stall value

1st Key In value

!=1st Stall value

1st digit correct?

Yes No2nd Key In

value==

2nd Stall value

2nd Key In value

!=2nd Stall value

2nd digit correct?

Yes No3rd Key In

value==

3rd Stall value

3rd Key In value

!=3rd Stall value

3rd digit correct?

Yes No4th Key In

value==

4th Stall value

4th Key In value

!=4th Stall value

4th digit correct?

LCD shows “Accessed”.

Green LED on. Buzzer beep once. Relay activated.

LCD shows “Denied”.

Red LED on. Buzzer beep twice.

Result?


Chapter 3 Test, Result and Discussion

After construction of the entire system, the hardware parts including the POWER SUPPLY

unit, the LCD unit, the KEYPAD and the LED BUZZER RELAY unit were tested on the

bread board while the software debugging was done using the MPLAB IDE.

3.1 POWER SUPPLY unit

From Figure 2.19, the yellow LED turns on to indicate the power is supplied. The value

output voltage of LM7805 and LM 7812 are also measured and recorded by using

voltmeter based on Figure 2.20 and 2.21.

3.2 LCD unit

To test LCD unit, connect to the MICROCONTROLLER PIC16F877A unit and the make sure the connection of the wire is correct connected. If the wire is connected correctly, the LCD will display the message that what your program inside the microcontroller. (The figure below is the program imported to microcontroller before transfer to PCB board.)

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Figure 2.20 Figure 2.21 show the value of output voltage

of LM 7805

Figure 2.19

Figure 2.22 Figure 2.23 Figure 2.24


3.3 KEYPAD unit

To test the KEYPAD unit, continuity test is taken to checking of an electric circuit to see

if current flows (that it is in fact a complete circuit). Based on Figure 2.7, when a key for

example ‘1’ is pressed, the 2 pin R4 and C3 will be shorted. I tested it by using multi-

meter, one of the probe will ‘touch’ the R4 and the another probe will ‘touch’ the C3(as

shown in Figure 2.24), the buzzer sounds on, the LED turns on at the same time and the

display of multi-meter with low value mean that is a connection between them.

3.4 LED BUZZER RELAY unit

At the same time you key in correct password, the green LED will turn on. On the other

side, the red LED will turn on when password is not matched with default password.

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Figure 2.24 Figure 2.26Figure 2.25

Figure 2.28Figure 2.27

http://en.wikipedia.org/wiki/Current_(electricity)

http://en.wikipedia.org/wiki/Electric_circuit


Chapter 4 Conclusion and Recommendation

4.1 Conclusions

In conclusion, the project worked and had met with the objectives set prior to the start of

the processes. The PIC is able to process the input data and display output data correctly

and accurately in breadboard. Unfortunately, the project had failed during the transferring

process of PCB.

During the process of transferring into PCB, a lot of important stuffs need to be take note.

For my opinion, we have to drill the pad of each component in PCB first and then draw

bigger the pad before etching it. This is because the copper pads which you draw by your

permanent marker pen are too small that will be spoiled during the drilling process. As a

result, the solder lead cannot stick on the copper pad and we need to melt large amount of

solder lead to make sure the leg of the component is connected to others. And this may

cause the beautifulness of the whole PCB.

In between, there are a lot of problems to be solved such as programming problem, circuit

connection problem, component defective and so on. All these problems are hard to be

identified with its death root causes but luckily with the help of some friends and

guidance from lecturers, the problems are solved.

Finally, I have also learned the importance of certain components to be installed to the

board. Before this, it is hard to understand why some components have to appear on the

board when its main function is not really relevant. This will improve my knowledge in

further use. I’m glad in developing a mini project.

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4.2 Recommendation

Due to the lacking of time, the limitation of this system is that the password set by the

user is stored in the RAM and hence it is lost when the supply is switched off. When the

supply is switched on again, the system is reset with the default password 1234.

Therefore, further improvement is that adding the feature of password can be changed by

the user and the changed password will be saved eternally in the EEPROM after the

power is switch off.

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References

Books

[1] Muhammad Ali Mazidi, Janice G. Mazidi, Rolin D. McKinlay, “The 8051 Microcontroller and Embedded Systems”, Second Edition, 2008.

Data Sheets:

[2] “PIC16F87XA 28/40/44-Pin Enhanced Flash Microcontrollers”, Data Sheet, MicroChip

[3] “LCD HD44780”, Data Sheet, Hitachi.

[4] “KA78XX/KA78XXA 3-Terminal 1A Positive Voltage Regulator”, Data Sheet, FairChild Semicondutor

Internet

[5] Cytron technologies

http://cytron.com.my/

[6] Anshuman Bezborah, “PIC Microcontroller-Based Electronic Lock”,

http://kitsnspares.com/admin/pdffiles/pic%20based%20electronic%20lock.pdf

[7] EAGLE Library – List of most commonly used electronics components

http://elecrom.wordpress.com/2009/10/09/eagle-library-list-of-most-commonly-used-

electronics-components/

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http://elecrom.wordpress.com/2009/10/09/eagle-library-list-of-most-commonly-used-electronics-components/

http://elecrom.wordpress.com/2009/10/09/eagle-library-list-of-most-commonly-used-electronics-components/

http://kitsnspares.com/admin/pdffiles/pic%20based%20electronic%20lock.pdf

http://cytron.com.my/

http://www.amazon.com/s/ref=ntt_athr_dp_sr_3?_encoding=UTF8&field-author=Rolin%20D.%20McKinlay&search-alias=books&sort=relevancerank

http://www.amazon.com/s/ref=ntt_athr_dp_sr_2?_encoding=UTF8&field-author=Janice%20G.%20Mazidi&search-alias=books&sort=relevancerank


Appendices

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Figure 3.0 Example of Password Door Security

Engineering

Report (Electromagnetic Password Door Lock System)