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

230 V AC 50 Hz 5V DC 12V step down transformer Filter(470µf) 5v RegulatorBridge rectifier

 It is a smaller computer  Has on-chip RAM, ROM, I/O ports... RAM ROM I/O Port Timer Serial COM Port Microcontroller CPU A single chip

CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial Port OSC Interrup t Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxD P0 P1 P2 P3 Address/Data Counter Inputs

 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

 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

 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

 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.

 “The 8051 Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi, Pearson Education.  ATMEL 89S52 Data Sheets.     