1. ELECTRONIC CODE LOCK DEVICE

2. CIRCUIT DESIGN OF ELECTRONIC CODE LOCK

3. INTRODUCTION
o Access control system that allows only authorized persons to access a
restricted area
o 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.

4.  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.

5. Block Diagram

6. 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

7. 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

8. 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

9. BLOCK DIAGRAM OF MICROCONTROLLER


10. PIN DIAGRAM


11.  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.

12. I/O PORT PINS AND THEIR FUNCTIONS
PORT 0:an 8-bit open drain bidirectional I/O port. It is the multiplexed
low-order address and data bus
PORT 1:an 8-bit bidirectional I/O port. P1.5, P1.6, P1.7 have high
current drive of 16mA
PORT 2:8-bit bidirectional I/O port, it receives control signals and a
partial of high-order address bits during the programming

13. LIQUID CRYSTAL DISPLAY
o Flat panel display, electronic visual display, video display that uses
the light modulating properties of liquid crystals .

14. 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

15. LCD Pin Description
16
16 Gnd
15
15 Vcc
14
14 D7
13
13 D6
12
12 D5
11
11 D4
10
10 D3
9
9 D2
8
8 D1
7 D0
3
7
6
6 E
5
5 R/W
4
4 RS
3
3 Contrast 2
2
2 Vcc
1
1 Gnd
1

16. POWER SUPPLY


17. 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

18. 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

19. 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

20. 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

21. REFERENCES
 www.electronicsforyou.com
 www.encyclopedia.com
 www.wikipedia.com