PIC Microcontroller Based Electronic Lock
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.
Update 28-8-2013
1. Here two circuit are provided, the smaller one works only forsimulation and the larger one works only in real world( Problem
with Pull Down resistors)
2. Due to frequent Requests I have Uploaded the HEX(8Mhz Crystal) file of these project in Our Facebook Group-Click Here