Digital Security Lock

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HITEC University Taxila Department of Electrical Engineering

Project Report

Anti Theft Lock

Participants Nisar Ahmed Rana

Shekh M. Arshad

Digital Security Lock

HITEC University Taxila 1

TABLE OF CONTENTS

Abstract 2 1 Introduction 3 1.1 Scope 3 2 Technical Background 4 3 Technical Approach 5

3.1 Preliminary Design 5 3.2 Programming the Microcontroller 5 3.3 Pseudo-Code & Flow Chart 6 3.4 Testing 7 3.4 Circuit Designing and Simulation 7 3.5 Practical Implementation 8 3.6 Troubleshooting 9

4 Circuit Explanation 10 4.1 Microcontroller Module 10 4.2 Power Board 11 4.3 LCD Board 12

5 Results and Conclusions 13 6 Future work 13 7 Appendix A 0

Appendix B 1 7.1 ATMEL AT89S52 Datasheet 1 7.2 ULN2003A Datasheet [2] 3 7.3 ABSOLUTE MAXIMUM RATINGS 4

8 Bibliography 5 8.1 References 5 8.2 Books 5



ABSTRACT

This project is a digital security lock made by using AT89S52 microcontroller. It is

designed for automobiles (i.e. SUZUKI MEHRAN). It will be attached on its dashboard

the user has a keypad for interaction and an LCD for instruction. The user will enter the

code when the instruction “Enter the Code” will appear on the LCD. In case of right code

it will grant the access to the user otherwise it will ask again three times. Failing to do

this the user have to enter the master code which is six digit if it is right then the user

have access to start the car otherwise the car will be locked and a security alarm start to

ring.



INTRODUCTION TO THIEF LOCK

Thief Lock contains a Keypad and an LCD screen. When the user wants to start the car

he will enter the six digit code the Microcontroller Unit will check the code for match; If

the code is verified then the car will start otherwise it will show an error message. The

user can enter wrong code for 3 times after that it will require the master code to start the

car.

SCOPE

This project has huge industrial applications. It can be used as automobiles Thief Lock

and can also be used as a code lock at many places. This code lock can be made more

secure by introducing finger print sensor with code.



TECHNICAL BACKGROUND

Security is a major concern in today world. The automobiles need new technologies for

their security. Different industries are working on automobiles security project such as

car tracker or digital locks. These code locks contains different techniques. Many of the

code lock are quite expensive which can‟t be used everywhere. We have also designed a

digital security lock for a car which contains a keypad to enter the code and an LCD to

display instructions on it. It consists on a microcontroller to control its operation. It is

simple but secure code lock which cost much less than the code locks manufactured by

different industries. It can be mounted on a car or can be attached separately with any

automobile. The same code lock can be used as a door lock the user has to interface the

motor and alarm with it.



Technical Approach

The design process of digital security lock consists on four steps.

1. Preliminary Design

2. Programming the Microcontroller

3. Circuit Designing and Simulation

4. Practical Implementation

5. Troubleshooting

PRELIMINARY DESIGN

Due to knowledge, gained till now, it has decided by our team that the design should be

as simple and secure as possible. Our motto was to design a simple and secure security

lock which can be usable for common person. Other factors for this consideration are cost

effect and limitation to embedded system design.

PROGRAMMING THE MICROCONTROLLER

After preliminary design our next job is to programme the microcontroller. We have used

C language to program the MCU (Microcontroller unit) in Keil. Keypad is interfaced

with port 1 and port 2 of MCU. LCD data pins are interfaced with port 3. Relays and

control pins of LCD are connected with port 0.

Programming of MCU consists on three different stages:

I. Writing a pseudo-code (Flow Chart)

II. Programming the LCD, Keypad and main circuit

III. Testing



PSEUDO-CODE & FLOW CHART

Flow chart of the program explains the logic of whole program. The flow chart is given

in figure-3.1

Pseudo Code for Keypad input:

Pins of Port 1 & Port 2 connected to row wires

Ro to R3 are set as input and the pins

connected to column wires C0 to C3 should be

set as outputs. (That is, pins 0–3 are inputs,

and 4–7 are outputs).

The outputs (bits 4–7) should be set to 0.

Whichever input (bits 0–3) reads in as 0

indicates the row of the pressed key.

Port 1 & Port 2 should then be reconfigured

to have the pins connected to row wires R0 to

R3 set as outputs, and the pins connected to

column wires C0 to C3 should be set as inputs.

(That is, bits 0–3 are outputs, and 4–7 are

inputs).

The outputs (bits 0–3) should be set to 0.

Whichever input (bits 4–7) reads in as 0 indicates the column of the pressed key.

Now that the row and column of the pressed key are known, the key can be located by

checking column and row position.

Pseudo-Code for LCD:

Check the D7 pin for busy condition of LCD (if D7=1 then wait until D7=0).

Send the data to D0-D7 (0x38) to initialize 5X7 matrix, (0x01) to clear screen, (0x02) to

go to home, (0x80) to go to the beginning of 1st line, (0xC0) to move to the beginning of

2nd line or (0x0F) to set the cursor blinking.

Set Rs & Rw ‘0’ and apply a 20ms high to low pulse to use it as a command.

Send the char as a data on D0-D7.

Set Rs=1 & Rw=0 and apply a 20ms high to low pulse to use it for printing data.



TESTING

After completing the whole code the program was debugged using KEIL debug tool. The

errors were corrected easily. We have created the object file in KEIL in INTEL *.hex file

format. The clock speed used was 11.0592MHz.

CIRCUIT DESIGNING AND SIMULATION

We have used Proteus 7.1 to simulate the circuit. After the placement of components and

connecting the wires we started the simulation. The AT89S52 Microcontroller was used

as a MCU. The INTEL *.hex generated by KEIL was selected as a source file. Clock

frequency was set to 11.0592MHz.

The schematic diagram of the circuit is given in Figure 4.1

Figure 3.1 Schematic Diagram During Simulation



PRACTICAL IMPLEMENTATION

After completing the simulation we have generated its PCBs using ARES a package of

Proteus. We placed the PCB packages of all the components we have used in schematic

diagram. After completing the PCB layout we have implemented it through the following

processes:-

Figure 4.1 PCB Layout of Power Board

PCB layout of power board is shown in the figure 4.1. This layout was printed on the

paper and then converted to printed circuit board.

PCB layout of microcontroller module is shown in figure 4.2. There was no PCB for

LCD board we made its circuit on zero board because it was a simple circuit and we have

to connect the wires parallel to the LCD.



Figure 4.2 PCB layout of Microcontroller Module.

TROUBLESHOOTING

Troubleshooting is one of the difficult task in designing a prototype of a project. After

completing all the circuits and making necessary connections we have faced some

problems in LCD display. The keypad and other circuits were working properly.

LCD does not display text: The whole port 3 and 3 pins of port 0 were checked. The pin

P0^0 was damaged so pin P0^1 was used in its place.

Text doesn’t hold on the LCD: Pins RS and E were interchanged so they were

corrected.

LCD didn’t show complete words: LCD didn‟t show complete words. Some of the

characters in a word were replaced with unwanted symbols. The reason for it is that we

haven‟t initialized the LCD before use but it work properly during simulation because it

doesn‟t need initialization.



Circuit Explanation

The complete circuit consists on the following three portions.

Microcontroller Module

Power Board

LCD Board

Figure 6.1 Schematic capture of Thief Lock. (Proteus 7.1)

MICROCONTROLLER MODULE

A microcontroller module has been used as a main circuit. It has parallel as well as serial

port communication circuits in it.



Figure 6.2 Circuit diagram of microcontroller module.

We have used parallel port communication. It has four IDC connectors connected to its

four ports. Clock and reset circuit are also on it.

POWER BOARD

Figure 6.3: 3D circuit layout of Power board



The four output ports are connected on the power board through IDC connectors. Port 1

and Port 2 are used for keypad. We have used four pins of each port for keypad. An eight

bit connector was used to connect the eight pins of two ports (4 pins per port). The

keypad is connected to this eight bit connector.

Port 3 is connected with eight bit data bus of LCD. Rs, R/W and E (enable) pins are used

from port 0. VCC, VEE & VDD are provided externally from the power board. These 14

pins are connected to another IDC connector which connects these 14 pins with LCD on

another board.

Two outputs from Port 0 are connected to ULN2003A which act as a current buffer. First

output is applied at pin 1A (pin # 1) and its output from pin 1C (pin # 14) is again

connected to pin 6A (pin # 6) and final output is taken at pin 6C (pin # 11). Second

output is applied at pin 2A (pin # 2) and its output from pin 2C (pin # 13) is again

connected to pin 7A (pin # 7) and final output is taken at pin 7C (pin # 10). This is done

due to two reasons. 1st is that the ULN2003 act as a logic inverter. It converts a „1‟ into

„0‟ and second time it is again inverted from „0‟ to „1‟. So we finally get the same output

which we have applied as an input with a current amplification. 2nd is that we need more

current to turn the relay on so due to double buffer we get enough current to derive a

relay.

The output of 1st relay is connected to the ignition coil of a car. The car will not start till

then relay is on (conducting). When the relay is off (cut) the signal will not reach to the

ignition coil so it will not start. When logic „1‟ came it gets amplified from ULN2003 and

turns the relay on so the car will start. The output of second relay is connected to a ringer.

When the user enter the Master (Administrator) password wrong for three attempts the

ringer will start ringing.

LCD BOARD

A small circuit is made using zero board. The 8 pin IDC connector take the LCD data

inputs from power board (Port 3) and connect them with this board. Here these pins are

connected with pin 7 to pin 14 of LCD. Pin 4, 5 & 6 are connected to port „0‟. A 5V

power is also provided on LCD board. Pin 1, 3 and 16 are connected to ground. Pin 2 and

15 are connected to +5V VCC.



Results and Conclusions

We were exposed to high levels of difficulty while we were working with the project. It

was a very good learning experience and at times we had to work with circuits and

concepts which were very new to us. We have tested it many times and also attached it

with a motor bike for practical testing. It worked well and was proved as a good digital

lock.

FUTURE WORK

This project can be used as a door lock at secure places by addition of finger prints sensor

module. The person has to enter the code and then finger print sensor will scan its finger

prints and then it will grant access.

Also it can be used as a wireless digital lock for automobiles. The person has to enter the

code from handheld module which will transmit then signal after verification to open the

car then he can start it. I am also working on it if a person breaks the whole system and

directly start the car then the handheld module or through mobile communication the user

can stop the car. It will send a signal to another module which directly cut the ignition

coil from batteries and it will stop. The car can also be tracked later on.



Appendix A

The whole programming code is given below.

#include <REGX51.H> #include<string.h> #define COL P2 #define ROW P1 void lcdcmd(unsigned char); void lcddata(unsigned char); void lcdprint(unsigned char *, unsigned char len); void lcdready(void); void msdelay(unsigned int); unsigned char getkey(void); bit check(unsigned char *,unsigned char *, unsigned char); void master_code(void); sfr ldata=0xB0; sbit rs=P0^0; sbit rw=P0^1; sbit en=P0^2; sbit busy=P3^7; sbit rel1=P0^3; sbit rel2=P0^4; unsigned char colloc, rowloc; unsigned char a[]="00077"; unsigned char master[6]="143143"; void main() { unsigned char ch[5]; unsigned char count; bit n; rel1=rel2=0; lcdcmd(0x38); lcdcmd(0x0E); lcdcmd(0x01); lcdcmd(0x85); lcdprint("Welcome",7); lcdcmd(0xC4); lcdprint("Theif Lock",10); msdelay(1000); lcdcmd(0x01); lcdcmd(0x80); count=0;



for(count=0;count<3;count++) { lcdprint("Enter The Code",14); lcdcmd(0xC0); lcdcmd(0x0F); ch[0]=getkey(); lcddata(ch[0]); ch[1]=getkey(); lcddata(ch[1]); ch[2]=getkey(); lcddata(ch[2]); ch[3]=getkey(); lcddata(ch[3]); ch[4]=getkey(); lcddata(ch[4]); msdelay(500); n=check(a,ch,5); if(n==1) { count=10; lcdcmd(0x01); lcdcmd(0x02); lcdprint("Access Granted",14); rel1=1; rel2=1; msdelay(500); } else { lcdcmd(0x01); lcdcmd(0x02); lcdprint("Access Denied",13); rel1=rel2=0; msdelay(500); } lcdcmd(0x01); lcdcmd(0x02); } if(count>5) { lcdcmd(0x01); lcdcmd(0x80); lcdprint("Thanx 4 Using",13); msdelay(50); lcdcmd(0xC0); lcdprint("Thief Lock",10); while(1); }



master_code(); lcdcmd(0x01); lcdcmd(0x02); lcdprint("Thanx 4 using",13); msdelay(25); lcdcmd(0xC0); lcdprint("Thief Lock",10); while(1); } void lcdcmd(unsigned char value) { lcdready(); ldata=value; rs=0; rw=0; en=1; msdelay(1); en=0; return; } void lcddata(unsigned char value) { lcdready(); ldata=value; rs=1; rw=0; en=1; msdelay(1); en=0; return; } void lcdprint(unsigned char *msg, unsigned char len) { int i; for(i=0;i<len;i++) { lcddata(msg[i]); } } void lcdready() { busy=1; rs=0; rw=1;



while(busy==1) { en=0; msdelay(1); en=1; } return; } unsigned char getkey() { while(1) { do { ROW=0x00; colloc=COL; colloc&=0x0F; } while(colloc!=0x0F); do { do { msdelay(20); colloc=COL; colloc&=0x0F; } while(colloc==0x0F); msdelay(20); colloc=COL; colloc&=0x0F; } while(colloc==0x0F); while(1) { ROW=0xFE; colloc=COL; colloc&=0x0F; if(colloc!=0x0F) { rowloc=0; break; } ROW=0xFD;



colloc=COL; colloc&=0x0F; if(colloc!=0x0F) { rowloc=1; break; } ROW=0xFB; colloc=COL; colloc&=0x0F; if(colloc!=0x0F) { rowloc=2; break; } ROW=0xF7; colloc=COL; colloc&=0x0F; rowloc=3; break; } if(colloc==0x0E&&rowloc==0) return('1'); else if(colloc==0x0E&&rowloc==1) return('4'); else if(colloc==0x0E&&rowloc==2) return('7'); else if(colloc==0x0E&&rowloc==3) return('*'); else if(colloc==0x0D&&rowloc==0) return('2'); else if(colloc==0x0D&&rowloc==1) return('5'); else if(colloc==0x0D&&rowloc==2) return('8'); else if(colloc==0x0D&&rowloc==3) return('0'); else if(colloc==0x0B&&rowloc==0) return('3'); else if(colloc==0x0B&&rowloc==1) return('6'); else if(colloc==0x0B&&rowloc==2) return('9'); else if(colloc==0x0B&&rowloc==3) return('#'); else if(colloc==0x07&&rowloc==0) return('A'); else if(colloc==0x07&&rowloc==1)



return('B'); else if(colloc==0x07&&rowloc==2) return('C'); else if(colloc==0x07&&rowloc==3) return('D'); } } bit check(unsigned char *b1,unsigned char *b2, unsigned char len) { int k=0; for(k=0;k<=len;k++) { if(b1[k]!=b2[k]) return(0); } return(1); } void master_code() { bit n; unsigned char count; unsigned char m[6]="362481"; while(1) { lcdprint("Enter Mastr Code",16); lcdcmd(0xC0); lcdcmd(0x0F); m[0]=getkey(); lcddata(m[0]); m[1]=getkey(); lcddata(m[1]); m[2]=getkey(); lcddata(m[2]); m[3]=getkey(); lcddata(m[3]); m[4]=getkey(); lcddata(m[4]); m[5]=getkey(); lcddata(m[5]); msdelay(500); n=check(master,m,6); count=0; if(n==1) { count=10; lcdcmd(0x01);



lcdcmd(0x02); lcdprint("Access Granted",14); rel1=1; rel2=0; msdelay(500); return; } else { lcdcmd(0x01); lcdcmd(0x02); lcdprint("Access Denied",13); rel1=rel2=0; msdelay(500);

lcdcmd(0x01); lcdcmd(0x02); if(count>=3) { rel1=0; rel2=1;

lcdprint("LOCKED",6); while(1);

} lcdcmd(0x01); lcdcmd(0x02); } } void msdelay(unsigned int time) { unsigned int i,j; for(i=0;i<time;i++) for(j=0;j<320;j++); }



Appendix B[1]

ATMEL AT89S52 DATASHEET

Compatible with MCS®-51 Products

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 1000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Full Duplex UART Serial Channel

Low-power Idle and Power-down Modes

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)

Green (Pb/Halide-free) Packaging Option

AT89C51 is available in three packages PDIP, PLCC and PQFP. We have used dual in line

package. Pin configuration of DIP with pin numbering is shown in figure A1.



Figure A1: Pin-Configuration of ATMEL AT89S52

Figure A2: Block diagram of AT89S52



ULN2003A DATASHEET [2]

Figure A3: Pin-Configuration of ULN2003A

Pin configuration with block diagram of ULN2003A is shown in figure A3. It has seven

input pins and seven output pins in front of the corresponding inputs for the purpose of

simplicity.

Figure A4



Series circuit of ULN2003A for single driver is shown in figure A4.

ABSOLUTE MAXIMUM RATINGS

Symbol Value Parameter Unit

Vo Output Voltage 50 V

Vin Input Voltage 30 V

IC Continuous Collector Current

500 mA

IB Continuous Base Current

25 mA

Tamb Operating Ambient Temperature Range

-20 to 85 oC

Tstg Storage Temperature Range

-55 to 150 oC

TJ Junction Temperature 150 oC0

Table A1 for absolute maximum ratings of ULN2003Q



BIBLIOGRAPHY

REFERENCES

[1] Datasheet, Type “ATMEL AT89S52”, Link http://www.google.com

[2] Datasheet, Type “ULN2003”, Link http://www.google.com

BOOKS

1) The 8051 Microcontroller and Embedded Systems, Edition “2nd”, Author

“Muhammad Ali Mazidi”, Publisher “Printice Hall”

2) Microcontroller 8051, Author “Hasanpur”, Company “Tehran University”

http://www.google.com/

http://www.google.com/

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