ELECTRIC LINE MAN SAFETY WITH PASSWORD BASED CIRCUIT BREAKER

Under the Guidance of

Submitted by

Project Title

ABSTRACT

The microcontroller based door locker is an access control

system that allows only authorized persons to access a

restricted area.

The system is fully controlled by the 8 bit microcontroller

which has an 8KB of ROM for the program memory.

The password is stored in microcontroller can be changed at

any time.

A matrix keypad is interfaced to the microcontroller to enter

the password while a relay driver IC is used to switch on

loads through relays.

BLOCK DIAGRAM

HARDWARE REQUIREMENTS

POWER SUPPLY BLOCK

MICROCONTROLLER (AT89S52/AT89C51)

PUSHBUTTON

LCD

MATRIX KEYPAD

RELAY

RELAY DRIVER

LED

1N4007

CAPACITORS

RESISTORS

POWER SUPPLY

230 V AC 50 Hz

5V DC

12V step down transformer

Filter(470µf)

5v RegulatorBridge rectifier

MICROCONTROLLER

It is a smaller computer Has on-chip RAM, ROM, I/O ports...

RAM ROM

I/O Port

TimerSerial COM Port

Microcontroller

CPU

A single chip

INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51

CPU

On-chip RAM

On-chip ROM for program code

4 I/O Ports

Timer 0

Serial Port

OSC

Interrupt Control

External interrupts

Timer 1

Timer/Counter

Bus

Control

TxD RxD

P0 P1 P2 P3

Address/Data

Counter Inputs

FEATURES OF AT89S51/52

Compatible with MCS®-51 Products

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 10,000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Full Duplex UART Serial Channel

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

PIN DESCRIPTION

RELAY

IT IS A ELECTRO MAGNETIC SWITCH

USED TO CONTROL THE ELECTRICAL DEVICES

COPPER CORE MAGNETIC FLUX PLAYS MAIN ROLE HERE

The relay's switch connections are usually labeled COM, NC and

NO:

COM = Common, always connect to this; it is the moving part of

the itch.

NC = Normally Closed, COM is connected to this when the relay

coil is off.

NO = Normally Open, COM is connected to this when the relay

coil is on

KEYPAD

A keypad is a set of buttons arranged in a block or

"pad" which usually bear digits, symbols and usually a

complete set of alphabetical letters. If it mostly contains

numbers then it can also be called a numeric keypad.

In order to detect which key is pressed from the matrix,

the row lines are to be made low one by one and read

the columns. Assume that if Row1 is made low, then

read the columns.

If any of the key in row1 is pressed then

correspondingly the column 1will give low that is if

second key is pressed in Row1, then column2 will give

low.

RELAY DRIVER (ULN 2003)

ULN2003 is a high voltage and high current Darlington transistor array

It consists of seven NPN Darlington pairs that feature high-

voltage outputs with common-cathode Clamp diode for

switching inductive loads.

The ULN2003 has a 2.7kW series base resistor for each

Darlington pair for operation directly with TTL or 5V

CMOS devices.

Current, Output Max:500mA

Voltage, Input Max:5V

Voltage, Output Max:50V

Fig: ULN 2003

LIQUID CRYSTAL DISPLAY (LCD)

Most common LCDs connected to the microcontrollers are

16x2 and 20x2 displays.

This means 16 characters per line by 2 lines and 20

characters per line by 2 lines, respectively.

The standard is referred to as HD44780U, which refers to

the controller chip which receives data from an external

source (and communicates directly with the LCD.

LCD BACKGROUND

If an 8-bit data bus is used the LCD will require 11 data lines

(3 control lines plus the 8 lines for the data bus)

The three control lines are referred to as EN, RS, and RW

EN=Enable (used to tell the LCD that you are sending it data)

RS=Register Select (When RS is low (0), data is treated as a command)

(When RS is High(1), data being sent is text data )

R/W=Read/Write (When RW is low (0), the data written to the LCD)

(When RW is low (0), the data reading to the LCD)

The numbers pressed in the matrix keypad load corresponding logical

state at the input i.e., port 1.

The program is so returned that when 1111 is pressed it switches ON

load 1 & while 2222 is pressed it switches ON load 2 and so on through

a relays interfaced through relay driver IC from the MC output

Working of project

SOFT WARE REQUIREMENTS

Keil an ARM Company makes C compilers, macro assemblers, real-

time kernels, debuggers, simulators, integrated environments,

evaluation boards, and emulators for ARM7/ARM9/Cortex-M3,

XC16x/C16x/ST10, 251, and 8051 MCU families.

Compilers are programs used to convert a High Level Language to

object code. Desktop compilers produce an output object code for the

underlying microprocessor, but not for other microprocessors.

i.e the programs written in one of the HLL like ‘C’ will compile the

code to run on the system for a particular processor like x86

(underlying microprocessor in the computer).

For example compilers for Dos platform is different from the

Compilers for Unix platform  So if one wants to define a compiler then

compiler is a program that translates source code into object code.

BIBILOGRAPHY “The 8051 Microcontroller and Embedded systems” by

Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson

Education.

ATMEL 89S52 Data Sheets.

www.atmel.com

www.beyondlogic.org

www.wikipedia.org

www.howstuffworks.com

www.alldatasheets.com