Code Lock Extreme Electronic

8/10/2019 Code Lock Extreme Electronic

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AVR ProjectATmega8 Based Smart Code Lock

Here is a project for beginners using Atmel AVR ATmega8. The project uses some techniques that

are very useful for designers to learn and utilize.

Alphanumeric LCD Module Interfacing.

44 Keypad interfacing.

PWM Control of LED(Used to dim the back-light of LCD, like in some Nokia Phones)

Basic Circuit design for AVR MCUs

Connecting relays and other current demanding devices.

AVR Studioand project management.

compiling using free avr-gcc compiler.

UsingeXtreme BurnerAVRto burn hex code to AVR MCU.

NOTE:

Dont waste time finding each part running from shop to shop. Get all the parts with exact

specification in a ready to use kit!Purchase ATmega8 based smart code lock KIT.
http://extremeelectronics.co.in/avr-tutorials/using-lcd-module-with-avrs/http://extremeelectronics.co.in/avr-tutorials/4x3-matrix-keypad-interface-avr-tutorial/http://extremeelectronics.co.in/avr-tutorials/4x3-matrix-keypad-interface-avr-tutorial/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://store.extremeelectronics.co.in/ATmega8-Based-Smart-Code-Lock-KIT.htmlhttp://store.extremeelectronics.co.in/ATmega8-Based-Smart-Code-Lock-KIT.htmlhttp://store.extremeelectronics.co.in/ATmega8-Based-Smart-Code-Lock-KIT.htmlhttp://store.extremeelectronics.co.in/ATmega8-Based-Smart-Code-Lock-KIT.htmlhttp://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/4x3-matrix-keypad-interface-avr-tutorial/http://extremeelectronics.co.in/avr-tutorials/using-lcd-module-with-avrs/


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Fig.: ATmega8 Based Code Lock
http://extremeelectronics.co.in/avrprojects/Images/CodeLockIso.jpghttp://extremeelectronics.co.in/avrprojects/Images/CodeLockIso.jpg


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Fig.: ATmega8 Based Code Lock Project

Functions of the Project.

This device can be used to code protect any electrical device (like an electronic door, lock orsafe).

The user must enter a correct password to gain access. The password is entered using the built in

44 keypad matrix. The mainLCD Moduleis used to display messages to the user. As soon as

correct password is entered the relay is activated. This is indicated by a LED which is placed near the

relay. The relay remains on as long as the user wishes. You just need to press a key to deactivate the

relay.

After typing four digit password you must press the "OK"button (S8). At anytime you may pressthe "Cancel"key (S12 )to clear the input (e.g. when you enter any incorrect digit)

The smart code lock has the feature to change the password too. For this enter a special password

which is 0000, as soon as the system receives this special password it switches to change password

mode. Here you need to enter the old password to gain permission, then enter the new password.

The smart code lock also support power saving feature. The backlight of LCD turns off automatically

when the system is idle for few seconds. The cool thing about this is that it usesPWM to control the

brightness of LCD Backlight.So the dimming is very smooth and it is like those used in many mobile

phones.
http://extremeelectronics.co.in/avrprojects/Images/CodeLockTop.jpghttp://en.wikipedia.org/wiki/Safehttp://en.wikipedia.org/wiki/Safehttp://en.wikipedia.org/wiki/Safehttp://shop.extremeelectronics.co.in/product_info.php?cPath=25&products_id=32http://shop.extremeelectronics.co.in/product_info.php?cPath=25&products_id=32http://shop.extremeelectronics.co.in/product_info.php?cPath=25&products_id=32http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avrprojects/Images/CodeLockTop.jpghttp://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://extremeelectronics.co.in/avr-tutorials/introduction-to-pwm-pulse-width-modulation/http://shop.extremeelectronics.co.in/product_info.php?cPath=25&products_id=32http://en.wikipedia.org/wiki/Safe


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Making it yourself!

You can fabricate the circuit on any general purpose PCB or breadboard. The schematic and the

BOM (Bill of Material is given below). To save you from lots of trouble we have made a quality PCB of

the same! If youpurchasethe PCB, you just need to solder different components at their proper placeon the PCB and you are ready to go.

Burn the HEX file (given at the end of article) to the ATmega8 MCU using anysuitable

programmerand plug it into the 28 PIN IC Socket.

After assembling the circuit power it on using a 12V 500ma Center Positive DC Wall adaptor (you can

use one that is used for mini TVs or Game Consols or Your DSL Modem). Adjust the variable resistor

RV1 (just below the LCD module, on the left side, yes the blue thing!) until the LCD Shows some text.

Schematic for ATmega8 based Smart Code Lock

Fig.: Complete Schematic (Click to Enlarge/Print)

Bill of Materials (BOM)Part List

01 330 ohm resistor (2 Nos) R3, R5

02 4k7 Resistor (3 Nos) R2, R4, R6
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03 200 Ohm Resistor R1

04 0.1uF Ceramic Disk Capacitor (4 Nos) C1, C3, C4, C5

05 1N4007 Diode (2 Nos) D1, D3

06LED

5mmAny ColourD4

07 ATmega8L-8PUGeneral purpose 8 bit MCU U1

087805

Voltage RegulatorU2

09 Power Connector 2 Way CON1

10 PCB Mountable Relay RL1

11 On/Off Switch SW1

12 DC Socket X1

13 162 LCD Module LCD1

14 10K Preset (Blue Plastic POT) RV1

15 28 PIN Narrow IC Socket

16 BC548 Transistor(2 Units) Q1, Q2

17 Push Buttons (16 Units)

18 ATmega8 Based Smart Code Lock PCB

Firmware Source Code

The firmware source code is written in a professional was that may seems confusing to a n00b

programmer. The thing is that every piece of related functions are stored in a separate source files.

That means the the project is composed of several C source file. Each C file has set of related

functions (like LCD Interfacing Routines or EEPROM Access). You must use AVR Studio as a project

manager and WinAVR as compiler. Both the software must be installed in your PC. In the project

folder their is a file with name "code_lock.aps" , this is the main AVR Studio Project file. Load it in

AVR Studio. You can see the various files that are part of the project in the left hand pane as shown

below. Double click any file to load in the editor. After a file has been loaded in editor you can view

and change it.
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Fig.: AVR Studio Main Window

The highest level file which contains the main application logic is "code_lock.c". This file containsthe main()function. The rest files are lower level files that provide service to the higher level files. If

you want to customize the firmware you can easily do so by editing the file "code_lock.c", in most

cases you do not have to touch the other C files.

Building the Binary from the source code.

You need to convert the high level human readable source code into machine language so that the

AVR chip can execute it. The complete process of this conversion is called "Building" (yes,

compilation is one of the steps of building). After build is complete you get a file called

"code_lock.hex" which is placed inside a folder called "default" inside the project folder. You just needto program this hex file to the ATmega8 MCU using anysuitable programmer.
http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/


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Fig.: AVR Studio Build Button

You can build the project using the "Build Active Configuration"button as shown above. You can

also hit F7 button or Select Bui ld from Bui ld Menu.

The Fuse bits must be set as follows. Consult your programmer software for more info.

HIGH=D9

LOW=E1

Please note that the above is default for ATmega8, so if you purchased a new chip then you do

not need to change them.

If you are new to AVR Studio and WinAVR Please read the following article carefully.

Hello World Project with AVR Studio and WinAVR.
http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/http://extremeelectronics.co.in/avr-tutorials/part-iv-the-hello-world-project/


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avr-gcc program for Code Lock

/**********************************************************************

********

Title:

ATmega8 Based Smart Code Lock.

Description:

A simple project for making a digital code lock. The main input

device is

a 4x4 Matrix Keypad. The main output is a 16x2 LCD Module.

The user has to enter a correct password to gain access. On receipt

of

correct password the relay is energized, which can be used to

operate

and device like an electronic door.

Their is facility for changing password.

For More information visit

http://www.eXtremeElectronics.co.in

Author:

Mandeep Tiwary under supervision of Avinash Gupta.


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[email protected]

[email protected]

Copyright:

eXtreme Electronics, India 2008- 2011

Notice:

No part of this work can be copied or published in electronic or

printed form without proper permission from the Original Creators.

ONLY INTENDED FOR EDUCATIONAL, HOBBY AND PERSONAL USE.

COMMERCIAL USE IS STRICTLY PROHIBITED.

Disclaimer of Warranty.

THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY

APPLICABLE LAW.

EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR

OTHER

PARTIES PROVIDE THE PROGRAM AS IS WITHOUT WARRANTY OF ANY KIND,

EITHER

EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

WARRANTIES

OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS

WITH YOU.

SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL

NECESSARY

SERVICING, REPAIR OR CORRECTION.


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***********************************************************************

*******/

#include

#include

#include

#include "lcd.h"

#include "keypad.h"

#include "user_interface.h"

#include "password_manager.h"

//LCD Backlight i/o configuration

#define LCDBL_PORT PORB

#define LCDBL_DDR DDRB

#define LCDBL_PIN PB1

//Output relay i/o configuration

#define RELAY_PORT PORTC

#define RELAY_DDR DDRC

#define RELAY_PIN PC0

//Simple Delay Function

voidWait(uint8_t n);

//Relay Control Functions

voidRelayOn();


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voidRelayOff();

//System Functions

voidSystemInit();

voidmain()

{

uint16_t password;

//Initialize the system

SystemInit();

while(1)

{

password=InputNumber("Enter Password");

//Match Password

if(password==ReadPassFromEEPROM())

{

LCDClear();

LCDWriteString("Access Granted");

//Now Activate Relay

RelayOn();

Wait(15);

LCDClear();


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LCDWriteString("Press Any Key");

//Now wait for any key

while(GetKeyPressed()==255)

{

_delay_loop_2(10);

}

//Now DeActivate Relay

RelayOff();

Wait(2);

}

else if(password==0)

{

/*

If user enters 0000 as password it

indicates a request to change password

*/

LCDClear();

password=InputNumber("Old Password");

if(password==ReadPassFromEEPROM())

{

//Allowed to change password


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uint16_t NewPassword;

NewPassword=InputNumber("New Password");

WritePassToEEPROM(NewPassword);

LCDClear();

LCDWriteString("Success !");

Wait(15);

}

else

{

//Not Allowed to change password

LCDClear();

LCDWriteString("Wrong Password !");

Wait(15);

}

}

else

{

LCDClear();

LCDWriteString("Access Denied");

RelayOff();

Wait(15);

}


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}

}

voidSystemInit()

{

//Set LCD Backlight Pin as output

LCDBL_DDR|=(1


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WritePassToEEPROM(1234);

}

}

voidWait(uint8_t n)

{

uint8_t i;

for(i=0;i


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Fig.: Code Lock PCB(PurchaseHere)
http://shop.extremeelectronics.co.in/product_info.php?cPath=50&products_id=841http://shop.extremeelectronics.co.in/product_info.php?cPath=50&products_id=841http://shop.extremeelectronics.co.in/product_info.php?cPath=50&products_id=841http://shop.extremeelectronics.co.in/product_info.php?cPath=50&products_id=841


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Fig.: Code Lock PCB (PurchaseHere)

Purchase Kit

Dont waste time finding each part running from shop to shop. Get all the parts with exact

specification in a ready to use kit!Purchase ATmega8 based smart code lock KIT.And help us

create more and more free AVR projects.

Downloads

Complete AVR Studio Project (ZIP File)

Precompiled hex file for burning to ATmega8 MCU

PCB Layouts in PDF, DOC and PNG Formats.
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