Circuit Diagram
Security is a prime concern in our day-today life. Everyone
wants to be as much secure as possible. An access control for doors forms a
vital link in a security chain. The microcontroller based digital lock for
Doors is an access control system that allows only authorized persons to access
a restricted area.
An electronic lock
or digital lock is a device which
has an electronic control assembly attached to it. They are provided with an
access control system. This system allows the user to
unlock the device with a password. The password is entered by making use of a
keypad. The user can also set his password to ensure better protection. The
major components include a Keypad, LCD and the controller PIC16F877A. This article describes the making of an electronic code lock using the
16F877A microcontroller.
The system is fully controlled by the 8 bit microcontroller 16F877A
which has a 8Kbytes of ROM for the program memory. The password is stored in
the EPROM so that we can change it at any time. The system has a Keypad by
which the password can be entered through it. When the entered password equals
with the password stored in the memory then the relay gets on and so that the
door is opened.
The code is built in a modular style to allow a user to find
ways to modify project. In start the D
Lock programs loads with a default code of "2345" format is *2345#
which can be enter to unlock the door, the code cam be change by entering the
master code in the format *23455#new 4 digit code. In this program i only display the result on
LCD and lock will be placed at PORTA
bit 0 where i put led for simulation.
A 4x3 matrix keypad
and a 16x2 LCD have been
used here. Keypad and LCD are very commonly used input & output devices,
respectively. The password is stored in the system EEPROM.
While unlocking, if the entered
password from keypad matches with the stored password, then the lock opens and
a message is displayed on LCD. Also an output pin is made high to be used for
further purpose..
As
the program starts, wait for 5sec and press * string ‘Enter Password’ is
displayed on LCD. The keypad is scanned for pressed digits one by one. Every
time, row and column of the key pressed is detected and is displayed on LCD. After
the four digits are entered, the user should press # to Confirm Password and
again the input is taken through LCD. If the passwords do not match, a message
is displayed to indicate ‘Access Denied’ otherwise the ‘Access Granted’
message.
The default password is 2345 and master key to
change password is 23455., entry begins with * and stops with #.
0 comments:
Post a Comment