ABSTRACT:

This project is aimed to design a digital code lock system with status display by using wireless communication technology RF.

                       Security is primary concern in our day-to-day life. Everyone wants to be as much as secure as to be possible. An access control systems forms a vital link in a security chain. By using this project an access control system that allows only authorized persons to access a restricted area. This system is best suitable for corporate offices, ATMs and home security.

                     Here the wireless communication between the remote areas can be achieved by using the RF modules called RF transmitter and RF receiver. This project is designed in such a way a digital keypad is interfaced to the controller ,on the transmitter side .The RF transmitter is also interfaced to the controller through an RF encoder to encode the data, i.e. the code which is entered by the keypad received by the controller. Hence the encoded data will be transmitted by the transmitter over the medium and will be received by the RF receiver which will be interfaced to the controller through an RF decoder, on the receiver side. The RF decoder is used to decode the received data into a 4 bit digital data which will be fed to the controller. Here an LCD will be interfaced to the controller on the receiver side to display the status of the lock. The received data by the decoder will be matched with the pre set value and the corresponding messages will be displayed on the LCD. If the data matches then lock will be opened and predefined message “unlocked” will be displayed on LCD. If it doesn’t match with the preset data then lock will not be opened and the predefined message “locked” will be displayed on LCD. 

       This project uses regulated 5V, 500mA power supply. Unregulated 12V DC is used for relay. 7805 three terminal voltage regulator is used for voltage regulation. Full wave bridge rectifier is used to rectify the ac output of secondary of 230/12V step down transformer.

TECHNICAL SPECIFICATIONS:

HARDWARE:

Micro controller         :           AT89S52                               Power supply

Crystal                        :           11.0592 MHz                             Transformer            : 12V step-down 

LCD                            :           HD44780                               Filter:1000uf/25V

Keypad                                                                            Voltage Regulator: 7805

RF transmitter             :           STT-433 MHz                       

RF receiver                 :           STT-433 MHz                       

RF encoder                 :           HT12E

RF decoder                 :           HT12D

SOFTWARE:

Keil micro vision

Proteus

UC flash

APPLICATIONS: Industrial applications