28-07-2012, 03:10 PM
SECURED ROOM ACCESS SYSTEM
[attachment=29405]
INTRODUCTION
Security is a prime concern in our day to day life
The microcontroller based digital lock presented here is an access control system that allows only authorized persons to access a restricted area
ATmega8535 microcontroller
It is a high performance, low power CMOS 8bit microcontroller
It is based on AVR enhanced RISC architecture
It has 8 kB of in system programmable flash memory with read while write capabilities
It has 512-byte EEPROM,512-byte SRAM,32 general purpose IO lines
LCD module
It has 8 bit data pins, are used to send information to the LCD or read the contents of LCD registers
It has 3 control pins RS,R/W,EN
One can send data as 8 bit or in pair of two 4 bit nibbles
To display any character on LCD ,µc has to send its ASCII value to the data bus of LCD
Keypad
The keypad here we are interfacing with the microcontroller is a matrix keypad(4×4)
Here for scanning and sensing 16 keys ,only 8 pins of µc are used
The rows are connected to 4 scan pins which are set in output mode and the columns are connected to sense pins which are set in input mode
Opto coupler
For transmitting signals and data from one sub system to another within a piece of electronic equipment these are used
These are available in small 6 pin or 8 pin IC packages
Opto coupler is mainly a combination of two components: An optical transmitter such as LED,an optical receiver such as photo transistor
Solenoid operated lock
Variable operating voltage range is 12 to 24 volts
Quick change in locked to unlocked position and vice versa
It is based on the operation of solenoid
Solenoids are important because they can create controlled magnetic fields
Circuit description
Main supply is given to step-down transformer, which gives an output of 9volts
This output is rectified using full wave bridge rectifier
Rectified output is regulated by a voltage regulator 7806IC and output is connected to relay
And the Circuit consists of an ATmega 8535 microcontroller.
Circuit description
PA0 pin of port A is connected to relay through optocoupler and transistor
Port C is interfaced with the LCD module
Port D is interfaced with the numeric keypad
An 8MHz crystal is used for providing an external clock to the microcontroller
LED present on the board ,glows when power is on
Switch S3 is used to reset the system
Working
When a person wants to enter the room, he enters the password ,if the password matches successfully, the gate is unlocked for a limited period of time
At the end of preset delay, the door gets locked again
When some one tries to enter the room, by entering invalid passwords continuously then the system locks itself and it can be unlocked only by the master user
Software implementation
The software for the AVR microcontroller is written in ‘C’ language and compiled using “code vision AVR ‘C’ compiler”
The source program is dumped on to the micro controller using AVR USB programmer
[attachment=29405]
INTRODUCTION
Security is a prime concern in our day to day life
The microcontroller based digital lock presented here is an access control system that allows only authorized persons to access a restricted area
ATmega8535 microcontroller
It is a high performance, low power CMOS 8bit microcontroller
It is based on AVR enhanced RISC architecture
It has 8 kB of in system programmable flash memory with read while write capabilities
It has 512-byte EEPROM,512-byte SRAM,32 general purpose IO lines
LCD module
It has 8 bit data pins, are used to send information to the LCD or read the contents of LCD registers
It has 3 control pins RS,R/W,EN
One can send data as 8 bit or in pair of two 4 bit nibbles
To display any character on LCD ,µc has to send its ASCII value to the data bus of LCD
Keypad
The keypad here we are interfacing with the microcontroller is a matrix keypad(4×4)
Here for scanning and sensing 16 keys ,only 8 pins of µc are used
The rows are connected to 4 scan pins which are set in output mode and the columns are connected to sense pins which are set in input mode
Opto coupler
For transmitting signals and data from one sub system to another within a piece of electronic equipment these are used
These are available in small 6 pin or 8 pin IC packages
Opto coupler is mainly a combination of two components: An optical transmitter such as LED,an optical receiver such as photo transistor
Solenoid operated lock
Variable operating voltage range is 12 to 24 volts
Quick change in locked to unlocked position and vice versa
It is based on the operation of solenoid
Solenoids are important because they can create controlled magnetic fields
Circuit description
Main supply is given to step-down transformer, which gives an output of 9volts
This output is rectified using full wave bridge rectifier
Rectified output is regulated by a voltage regulator 7806IC and output is connected to relay
And the Circuit consists of an ATmega 8535 microcontroller.
Circuit description
PA0 pin of port A is connected to relay through optocoupler and transistor
Port C is interfaced with the LCD module
Port D is interfaced with the numeric keypad
An 8MHz crystal is used for providing an external clock to the microcontroller
LED present on the board ,glows when power is on
Switch S3 is used to reset the system
Working
When a person wants to enter the room, he enters the password ,if the password matches successfully, the gate is unlocked for a limited period of time
At the end of preset delay, the door gets locked again
When some one tries to enter the room, by entering invalid passwords continuously then the system locks itself and it can be unlocked only by the master user
Software implementation
The software for the AVR microcontroller is written in ‘C’ language and compiled using “code vision AVR ‘C’ compiler”
The source program is dumped on to the micro controller using AVR USB programmer