INTRODUCTIONo Access control system that allows only authorized persons to access a restricted areao Allows the user to unlock the device with a password.o The major components include a keypad, LCD and the controller P89V51 which belongs to the 8051 series of microcontrollers.o User can also set his password to ensure better protection.
Can be adapted to any electronic gadget which needs to be protected from unauthorised persons/access. Responds only to the right sequence of four digits that are keyed in remotely. If a wrong key is touched, it resets the lock.
COMPONENTS USED IN THE DEVICE LCD 16*2 Resistors 10k*12, 1k*10, 1.5k Crystal 11.0592Hz Capacitors 33pF*2, 10µF, 0.1µF*3 IC7805 Battery power 9V Switches LED‟s Connecting wires Microcontroller P89V51
MICROCONTROLLER P89V51 16/32/64 kB flash and 1024 B of data RAM A key feature of the P89V51 is its X2 mode option. The flash program memory supports both parallel programming and in serial ISP Supports 12-clock (default) or 6-clock mode selection via software or ISP
Features 80C51 CPU 5 V operating voltage from 0 MHz to 40 MHz 16/32/64 kB of on-chip flash user code memory PCA (programmable counter array) with capture/compare functions Four 8-bit I/O ports with three high-current port 1 pins Three 16-bit timers/counters
Vcc-Pin 40 provides supply voltage to the chip. The voltage source is +5 V. GND- Pin 20 is the ground. RST-Pin 9 is the reset pin. It is an input and is active high (normally low). EA pin is connected to the Vcc and connected to pin no. 31. PSEN is “program store enable.” It is the read strobe to external program memory. ALE is output pin and is active high. When connecting a microcontroller to external memory, port 0 provides both address and data.
I/O PORT PINS AND THEIR FUNCTIONSPORT 0:an 8-bit open drain bidirectional I/O port. It is the multiplexed low-order address and data busPORT 1:an 8-bit bidirectional I/O port. P1.5, P1.6, P1.7 have high current drive of 16mAPORT 2:8-bit bidirectional I/O port, it receives control signals and a partial of high-order address bits during the programming
LIQUID CRYSTAL DISPLAYo Flat panel display, electronic visual display, video display that uses the light modulating properties of liquid crystals .
APPLICATIONS Used in computer monitors, television, instrument panels, aircraft cockpit displays, signage, etc an electronically modulated optical device made up of any number of segments filled with liquid crystals and arrayed in front of a light source or reflector to produce images in monochrome Also used in video players, gaming devices, clocks, watches, calculators, and telephones and have wide range of screen sizes
COMPONENTS USED The transformer steps down the 220 V a/c. into 12 V a/c A rectifier transforms ac into dc by limiting. The output resulting from a rectifier is a pulsating D.C. voltage The ripple of the D.C. voltage is smoothened using a filter capacitor The voltage regulator regulates the supply if the supply if the line voltage increases or decreases
WORKING OF PROJECT As the program starts, string „Enter Password‟ is displayed on LCD After the four digits are entered, the user is prompted to „Confirm Password‟ If the passwords do not match, a message is displayed to indicate „Wrong Password‟ Again the keypad is scanned for pressed keys and corresponding digits are identified If all the four digits match with set password, the lock output pin goes high The system gets locked if more than three attempts are made with wrong password to open the electronic lock The high output of the logic circuit enables the AND gate
APPLICATIONS: used to automate the door locking process, so the user need not to carry the door lock keys used in Mobile phones for security purposes Used in Banks lockers used in applications like Lift, Telephone Locking, Refrigerators etc
RESULT AND CONCLUSION Result:-all electronics devices plays very important role in Programming and in Electronics Department Conclusion:-All electronics devices can perform many functions using interfacing and programming with Embedded C language Future scope:-In future, the improved version of Microcontrollers will be more useful.In serial communication and Robotics, everywhere we need Microcontrollers to store program in it