AUTOMATIC AMBULANCE RESCUE SYSTEM CORDIALITY SERVICES

TITLE

PROJECT REPORT

PHASE I

Submitted by

Register No:

in partial fulfillment for the award of the degree

Of

MASTER OF ENGINEERING

In

APPLIED ELECTRONICS

PAAVAI ENGINEERING COLLEGE

PACHAL, NAMAKKAL – 637 018

ANNA UNIVERSITY OF TECHNOLOGY

COIMBATORE – 641 001

NOVEMBER 2010

ACKNOWLEDGEMENT

A great deal of time and effort has been spent in completing this project work. Several people

have guided us and contributed significantly to this effort and so this becomes obligatory to

record my thanks to them.

I express my profound gratitude to our honorable Chairman, Shri.CA.N.V.NATARAJAN,

B.Com., F.C.A., and also to our Correspondent, Smt.MANGAI NATARAJAN, M.Sc., for

providing all necessary facilities for the successful completion of the project.

I have immense pleasure in expressing our gratitude to our beloved Principal,

Dr.C.JEGADHEESAN, Ph.D., for allowing us to have the extensive use of our college

facilities to do this project.

I express my heartiest gratitude to Assistant Professor& Head of the Department, for his

guidance and encouragement. I am indebted to my internal guide Assistant Professor,

Department of Electronics and Communication Engineering for her constant help and excellent

creative ideas over the period of project work.

I express my sincere words of gratitude to the staff members of the Department of Electronics

and Communication Engineering for their encouragement to do the project work with full

interest and enthusiasm.

I would like to extend my warmest thanks to all our Lab Technicians for helping me in this

venture. Unflinching support and encouragement from the members of my family, friends and all

staff members in PAAVAI ENGINEERING COLLEGE helped me a long way to complete

my project work. I must thank them all from the depth of my

heart. Mrs.K.NIRMALA DEVI,M.Tech .,(Ph.D)., Mr.R.ARANGASAMY, M.Tech.,(Ph.D).,

2. ABSTRACT:

Traffic congestion and tidal flow management were recognized as major problems

in modern urban areas, which have caused much warting for the ambulance.

Moreover road accidents in the city have been incessant and to bar the loss of life

due to the accidents is even more crucial. To implement this we introduce a

scheme called AARS (Automatic ambulance rescue system). The main theme

behind this scheme is to provide a smooth flow for the ambulance to reach the

hospitals in time and thus minifying the expiration. The idea behind this scheme is

to implement a ITS which would control mechanically the traffic lights in the path

of the ambulance. The ambulance is controlled by the central unit which furnishes

the most scant route to the ambulance and also controls the traffic light according

to the ambulance location and thus reaching the hospital safely. The server also

determines the location of the accident spot through the sensor systems in the

vehicle which encountered the accident and thus the server walks through the

ambulance to the spot. This scheme is fully automated, thus it finds the accident

spot, controls the traffic lights, helping to reach the hospital in time.

3. INTRODUCTION

Present industry is increasingly shifting towards automation. Two principle

components of today’s industrial automations are programmable controllers and

robots. In order to aid the tedious work and to serve the mankind, today there is a

general tendency to develop an intelligent operation.

The proposed system “AUTOMATIC AMBULANCE RESCUE SYSTEM

CORDIALITY SERVICES” is designed and developed to accomplish the

various tasks in an adverse environment of an industry. The intelligent This project

is an owe to the technical advancement. This prototype system can be applied

effectively and efficiently in an expanded dimension to fit for the requirement of

industrial, research and commercial applications.

Microcontroller is the heart of the device which handles all the sub devices

connected across it. We have used as microcontroller. It has flash type

reprogrammable memory. It has some peripheral devices to play this project

perform. It also provides sufficient power to inbuilt peripheral devices. We need

not give individually to all devices. The peripheral devices also activates as low

power operation mode. These are the advantages are appear here.

4. EXISTING SYSTEM:

Vehicle Accident Automatic Detection and Remote AlarmDevice

The Rapid growth of technology and infrastructure has made our lives easier. The

advent of technology has also increased the traffic hazards and the road accident

take place frequently which causes huge loss of life and property because of the

poor emergency facilities. Our project will provide an optimum solution to this

draw back. An accelerometer can be used in a car alarm application so that

dangerous driving can be detected. It can be used as a crash or rollover detector of

the vehicle during and after a crash. With signals from an accelerometer, a severe

accident can be recognized. According to this project when a vehicle meets with an

accident immediately Vibration sensor will detect the signal or if a car rolls over,

and Micro electro mechanical system (MEMS) sensor will detects the signal and

sends it to ARM controller. Microcontroller sends the alert message through the

GSM MODEM including the location to police control room or a rescue team. So

the police can immediately trace the location through the GPS MODEM, after

receiving the information. Then after conforming the location necessary action will

be taken. If the person meets with a small accident or if there is no serious threat to

anyone`s life, then the alert message can be terminated by the driver by a switch

provided in order to avoid wasting the valuable time of the medical rescue team.

This paper is useful in detecting the accident precisely by means of both vibration

sensor and Micro electro Mechanical system (MEMS) or accelerometer. As there

is a scope for improvement and as a future implementation we can add a wireless

webcam for capturing the images which will help in providing driver`s assistance.

5. SYSTEM SPECIFICATION:

5.1 HARDWARE REQUIREMENT:

PIC MICROCONTROLLER MICROCONTROLLER LCD DISPLAY RS 232 GSM MODEM PC VIBRATION SENSOR KEYPAD RF TRANSMITTER &RECIVER ENCODER & DECODER TRAFFIC LIGHT KEY RELAY

5.2SOFTWARE REQUIREMENT:

MPLAP PCB DESIGNING

6. SOFTWARE DESCRIPTION:

6.1 MPLAB

MPLAB IDE is an integrated development environment that provides

development engineers with the flexibility to develop and debug firmware for

various Microchip devices

MPLAB IDE is a Windows-based Integrated Development Environment for the

Microchip Technology Incorporated PICmicrocontroller (MCU) and dsPIC digital

signal controller (DSC) families. In the MPLAB IDE, you can:

Create source code using the built-in editor.

Assemble, compile and link source code using various language tools. An

assembler, linker and librarian come with MPLAB IDE. C compilers are

available from Microchip and other third party vendors.

Debug the executable logic by watching program flow with a simulator,

such as MPLAB SIM, or in real time with an emulator, such as MPLAB

ICE. Third party emulators that work with MPLAB IDE are also available.

Make timing measurements.

View variables in Watch windows.

Program firmware into devices with programmers such as PICSTART Plus

or PRO MATE II.

Find quick answers to questions from the MPLAB IDE on-line Help.

MPLAB SIMULATOR

MPLAB SIM is a discrete-event simulator for the PIC microcontroller (MCU)

families.  It is integrated into MPLAB IDE integrated development environment.

The MPLAB SIM debugging tool is designed to model operation of Microchip

Technology's PIC microcontrollers to assist users in debugging software for these

devices

IC PROG

The PRO MATE II is a Microchip microcontroller device programmer. Through

interchangeable programming socket modules, PRO MATE II enables you to

quickly and easily program the entire line of Microchip PICmicro microcontroller

devices and many of the Microchip memory parts.

PRO MATE II may be used with MPLAB IDE running under supported Windows

OS's (see Read me for PRO MATE II.txt for support list), with the command-line

controller PROCMD or as a stand-alone programmer

COMPILER-HIGH TECH C

A program written in the high level language called C; which will be converted

into PICmicro MCU machine code by a compiler. Machine code is suitable for use

by a PICmicro MCU or Microchip development system product like MPLAB IDE.

PIC START PLUS PROGRAMMER:

The PIC start plus development system from microchip technology

provides the product development engineer with a highly flexible low cost

microcontroller design tool set for all microchip PIC micro devices. The pic start

plus development system includes PIC start plus development programmer and

MPLAB IDE.

The PIC start plus programmer gives the product developer ability to

program user software in to any of the supported microcontrollers. The PIC start

plus software running under MPLAB provides for full interactive control over the

programmer.

6.2PCB DESIGNING

Design and Fabrication of Printed circuit boards

INTRODUCTION:

Printed circuit boards, or PCBs, form the core of electronic equipment

domestic and industrial. Some of the areas where PCBs are intensively used are

computers, process control, telecommunications and instrumentation.

MANUFATCURING:

The manufacturing process consists of two methods; print and etch, and

print, plate and etch. The single sided PCBs are usually made using the print and

etch method. The double sided plate through – hole (PTH) boards are made by the

print plate and etch method.

The production of multi layer boards uses both the methods. The inner layers

are printed and etch while the outer layers are produced by print, plate and etch

after pressing the inner layers.

SOFTWARE:

The software used in our project to obtain the schematic layout is

MICROSIM.

PANELISATION:

Here the schematic transformed in to the working positive/negative films. The circuit is repeated conveniently to accommodate economically as many circuits as possible in a panel, which can be operated in every sequence of subsequent steps in the PCB process. This is called penalization. For the PTH boards, the next operation is drilling.

DRILLING:

PCB drilling is a state of the art operation. Very small holes are drilled with

high speed CNC drilling machines, giving a wall finish with less or no smear or

epoxy, required for void free through hole plating.

PLATING:

The heart of the PCB manufacturing process. The holes drilled in the board

are treated both mechanically and chemically before depositing the copper by the

electro less copper platting process.

ETCHING:

Once a multiplayer board is drilled and electro less copper deposited, the

image available in the form of a film is transferred on to the out side by photo

printing using a dry film printing process. The boards are then electrolytic plated

on to the circuit pattern with copper and tin. The tin-plated deposit serves an etch

resist when copper in the unwanted area is removed by the conveyor’s spray

etching machines with chemical etch ants. The etching machines are attached to an

automatic dosing equipment, which analyses and controls etch ants concentrations

SOLDERMASK:

Since a PCB design may call for very close spacing between conductors, a

solder mask has to be applied on the both sides of the circuitry to avoid the

bridging of conductors. The solder mask ink is applied by screening. The ink is

dried, exposed to UV, developed in a mild alkaline solution and finally cured by

both UV and thermal energy.

HOT AIR LEVELLING:

After applying the solder mask, the circuit pads are soldered using the hot air

leveling process. The bare bodies fluxed and dipped in to a molten solder bath.

While removing the board from the solder bath, hot air is blown on both sides of

the board through air knives in the machines, leaving the board soldered and

leveled. This is one of the common finishes given to the boards. Thus the double

sided plated through whole printed circuit board is manufactured and is now ready

for the components to be soldered.

7. HARD WARE DESCRIPTION:

7. 1 BLOCK DIAGRAM:

7.2 BLOCK DIAGRAM DESCRIPTION:

7.2.1 PIC MICRO CONTROLLER

CONCEPTS OF MICROCONTROLLER :

Microcontroller is a general

purpose device, which integrates a number of the components of a

microprocessor system on to single chip. It has inbuilt CPU, memory and

peripherals to make it as a mini computer. A microcontroller combines on to the

same microchip:

The CPU core

Memory(both ROM and RAM)

Some parallel digital i/o

Microcontrollers will combine other devices such as:

A timer module to allow the microcontroller to perform tasks for certain

time periods.

A serial i/o port to allow data to flow between the controller and other

devices such as a PIC or another microcontroller.

An ADC to allow the microcontroller to accept analogue input data for

processing.

Microcontrollers are :

Smaller in size

Consumes less power

Inexpensive

Micro controller is a stand alone unit ,which can perform functions

on its own without any requirement for additional hardware like i/o ports and

external memory.

The heart of the microcontroller is the CPU core. In the past, this has traditionally

been based on a 8-bit microprocessor unit. For example Motorola uses a basic

6800 microprocessor core in their 6805/6808 microcontroller devices.

In the recent years, microcontrollers have been

developed around specifically designed CPU cores, for example the microchip PIC

range of microcontrollers.

INTRODUCTION TO PIC :

The microcontroller that has been used for this

project is from PIC series. PIC microcontroller is the first RISC based

microcontroller fabricated in CMOS (complimentary metal oxide semiconductor)

that uses separate bus for instruction and data allowing simultaneous access of

program and data memory.

The main advantage of CMOS and RISC

combination is low power consumption resulting in a very small chip size with a

small pin count. The main advantage of CMOS is that it has immunity to noise

than other fabrication techniques.

PIC (16F877) :

Various microcontrollers offer different kinds of

memories. EEPROM, EPROM, FLASH etc. are some of the memories of which

FLASH is the most recently developed. Technology that is used in pic16F877 is

flash technology, so that data is retained even when the power is switched off.

Easy Programming and Erasing are other features of PIC 16F877.

PIC START PLUS PROGRAMMER :

The PIC start plus development system from

microchip technology provides the product development engineer with a highly

flexible low cost microcontroller design tool set for all microchip PIC micro

devices. The picstart plus development system includes PIC start plus development

programmer and mplab ide.

The PIC start plus programmer gives the product developer

ability to program user software in to any of the supported microcontrollers. The

PIC start plus software running under mplab provides for full interactive control

over the programmer.

SPECIAL FEATURES OF PIC MICROCONTROLLER :

CORE FEATURES :

• High-performance RISC CPU

• Only 35 single word instructions to learn

• All single cycle instructions except for program branches which are two cycle

• Operating speed: DC - 20 MHz clock input

DC - 200 ns instruction cycle

• Up to 8K x 14 words of Flash Program Memory,

Up to 368 x 8 bytes of Data Memory (RAM)

Up to 256 x 8 bytes of EEPROM data memory

• Pin out compatible to the PIC16C73/74/76/77

• Interrupt capability (up to 14 internal/external

• Eight level deep hardware stack

• Direct, indirect, and relative addressing modes

• Power-on Reset (POR)

• Power-up Timer (PWRT) and Oscillator Start-up Timer (OST)

• Watchdog Timer (WDT) with its own on-chip RC Oscillator for reliable

operation

• Programmable code-protection

• Power saving SLEEP mode

• Selectable oscillator options

• Low-power, high-speed CMOS EPROM/EEPROM technology

• Fully static design

• In-Circuit Serial Programming (ICSP) via two pins

• Only single 5V source needed for programming capability

• In-Circuit Debugging via two pins

• Processor read/write access to program memory

• Wide operating voltage range: 2.5V to 5.5V

• High Sink/Source Current: 25 mA

• Commercial and Industrial temperature ranges

• Low-power consumption:

< 2mA typical @ 5V, 4 MHz

20mA typical @ 3V, 32 kHz

< 1mA typical standby current

PERIPHERAL FEATURES :

• Timer0: 8-bit timer/counter with 8-bit prescaler

• Timer1: 16-bit timer/counter with prescaler, can be incremented during sleep

via external crystal/clock

• Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler

• Two Capture, Compare, PWM modules

Capture is 16-bit, max resolution is 12.5 ns,

Compare is 16-bit, max resolution is 200 ns,

PWM max. resolution is 10-bit

• 10-bit multi-channel Analog-to-Digital converter

• Synchronous Serial Port (SSP) with SPI. (Master Mode) and I2C.

(Master/Slave)

• Universal Synchronous Asynchronous Receiver Transmitter (USART/SCI) with

9- bit address detection.

• Brown-out detection circuitry for Brown-out Reset (BOR)

ARCHITECTURE OF PIC 16F877 :

The complete architecture of PIC

16F877 is shown in the fig 2.1. Table 2.1 gives details about the specifications of

PIC 16F877. Fig 2.2 shows the complete pin diagram of the IC PIC 16F877.

ARCHITECTURE OF PIC 16F877

SPECIFICATIONS

PIN DIAGRAM OF PIC 16F877

DEVICE PROGRAM FLASHDATA

MEMORY

DATA

EEPROM

PIC

16F8778K 368 Bytes 256 Bytes

PIN OUT DESCRIPTION

Legend: I = input O = output I/O = input/output P = power

— = Not used TTL = TTL input ST = Schmitt Trigger input

Note

1. This buffer is a Schmitt Trigger input when configured as an external interrupt

2. This buffer is a Schmitt Trigger input when used in serial programming mode.

3. This buffer is a Schmitt Trigger input when configured as general purpose I/O

and a TTL

input when used in the Parallel Slave Port mode (for interfacing to a

microprocessor bus).

4. This buffer is a Schmitt Trigger input when configured in RC oscillator mode

and a

CMOS input otherwise.

Legend: I = input O = output I/O = input/output P = power

— = Not used TTL = TTL input ST = Schmitt Trigger input

Note :

1. This buffer is a Schmitt Trigger input when configured as an external interrupt.

2. This buffer is a Schmitt Trigger input when used in serial programming mode.

3. This buffer is a Schmitt Trigger input when configured as general purpose I/O

and a TTL

input when used in the Parallel Slave Port mode (for interfacing to a

microprocessor bus).

4. This buffer is a Schmitt Trigger input when configured in RC oscillator mode

and a

CMOS input otherwise.

2.5 I/O PORTS :

Some pins for these I/O ports are multiplexed with an alternate

function for the peripheral features on the device. In general, when a peripheral is

enabled, that pin may not be used as a general purpose I/O pin.

Additional Information on I/O ports may be found in the IC

micro™ Mid-Range Reference Manual,

PORTA AND THE TRISA REGISTER :

PORTA is a 6-bit wide bi-directional port. The corresponding

data direction register is TRISA. Setting a TRISA bit (=1) will make the

corresponding PORTA pin an input, i.e., put the corresponding output driver in a

Hi-impedance mode. Clearing a TRISA bit (=0) will make the corresponding

PORTA pin an output, i.e., put the contents of the output latch on the selected pin.

Reading the PORTA register reads the status of the

pins whereas writing to it will write to the port latch. All write operations are read-

modify-write operations. Therefore a write to a port implies that the port pins are

read; this value is modified, and then written to the port data latch. Pin RA4 is

multiplexed with the Timer0 module clock input to become the RA4/T0CKI pin.

The RA4/T0CKI pin is a Schmitt Trigger input and an open drain output. All other

RA port pins have TTL input levels and full CMOS output drivers. Other PORTA

pins are multiplexed with analog inputs and analog VREF input. The operation of

each pin is selected by clearing/setting the control bits in the ADCON1 register

(A/D Control Register1).

The TRISA register controls the direction of the RA pins, even when they

are being used as analog inputs. The user must ensure the bits in the TRISA

register are maintained set when using them as analog inputs.

PORT A FUNCTION

Legend: TTL = TTL input, ST = Schmitt Trigger input

SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Legend: x = unknown, u = unchanged, - = unimplemented locations

read as '0'. Shaded cells are not used by PORTA.

PORTB AND TRISB REGISTER :

PORTB is an 8-bit wide bi-directional port.

The corresponding data direction register is TRISB. Setting a TRISB bit (=1) will

make the corresponding PORTB pin an input, i.e., put the corresponding output

driver in a hi-impedance mode. Clearing a TRISB bit (=0) will make the

corresponding PORTB pin an output, i.e., put the contents of the output latch on

the selected pin. Three pins of PORTB are multiplexed with the Low Voltage

Programming function; RB3/PGM, RB6/PGC and RB7/PGD. The alternate

functions of these pins are described in the Special Features Section. Each of the

PORTB pins has a weak internal pull-up. A single control bit can turn on all the

pull-ups.

This is performed by clearing bit RBPU

(OPTION_REG<7>). The weak pull-up is automatically turned off when the port

pin is configured as an output. The pull-ups are disabled on a Power-on Reset.

Four of PORT B’s pins, RB7:RB4, have an interrupt on

change feature. Only pins configured as inputs can cause this interrupt to occur

(i.e. any RB7:RB4 pin configured as an output is excluded from the interrupt on

change comparison). The input pins (of RB7:RB4) are compared with the old value

latched on the last read of PORTB. The “mismatch” outputs of RB7:RB4 are

OR’ed together to generate the RB Port Change Interrupt with flag bit RBIF

(INTCON<0>). This interrupt can wake the device from SLEEP. The user, in the

interrupt service routine, can clear the interrupt in the following manner:

a) Any read or write of PORTB. This will end the mismatch condition.

b) Clear flag bit RBIF. A mismatch condition will continue to set flag

bit RBIF. Reading PORTB will end the mismatch condition, and allow flag bit

RBIF to be cleared. The interrupt on change feature is recommended for wake-up

on key depression operation and operations where PORTB is only used for the

interrupt on change feature. Polling of PORTB is not recommended while using

the interrupt on change feature. This interrupt on mismatch feature, together with

software configurable pull-ups on these four pins, allow easy interface to a keypad

and make it possible for wake-up on key depression

PORT B FUNCTIONS

SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

PORTC AND THE TRISC REGISTER :

PORTC is an 8-bit wide bi-directional port.

The corresponding data direction register is TRISC. Setting a TRISC bit (=1) will

make the corresponding PORTC pin an input, i.e., put the corresponding output

driver in a hi-impedance mode. Clearing a TRISC bit (=0) will make the

corresponding PORTC pin an output, i.e., put the contents of the output latch on

the selected pin. PORTC is multiplexed with several peripheral functions. PORTC

pins have Schmitt Trigger input buffers.

When the I2C module is enabled, the

PORTC (3:4) pins can be configured with normal I2C levels or with SMBUS

levels by using the CKE bit (SSPSTAT <6>). When enabling peripheral functions,

care should be taken in defining TRIS bits for each PORTC pin. Some peripherals

override the TRIS bit to make a pin an output, while other peripherals override the

TRIS bit to make a pin an input. Since the TRIS bit override is in effect while the

peripheral is enabled, read-modify write instructions (BSF, BCF, XORWF) with

TRISC as destination should be avoided. The user should refer to the

corresponding peripheral section for the correct TRIS bit settings.

PORTC FUNCTIONS

SUMMARY OF REGISTERS ASSOCIATED WITH PORTC

PORTD AND TRISD REGISTERS :

This section is not applicable to the 28-pin

devices. PORTD is an 8-bit port with Schmitt Trigger input buffers. Each pin is

individually configurable as an input or output. PORTD can be configured as an 8-

bit wide microprocessor Port (parallel slave port) by setting control bit PSPMODE

(TRISE<4>). In this mode, the input buffers are TTL.

PORTD FUNCTIONS

SUMMARY OF REGISTERS ASSOCIATED WITH PORTD

PORTE AND TRISE REGISTER :

PORTE has three pins RE0/RD/AN5,

RE1/WR/AN6 and RE2/CS/AN7, which are individually configurable as inputs or

outputs. These pins have Schmitt Trigger input buffers.

The PORTE pins become control inputs for the

microprocessor port when bit PSPMODE (TRISE<4>) is set. In this mode, the user

must make sure that the TRISE<2:0> bits are set (pins are configured as digital

inputs). Ensure ADCON1 is configured for digital I/O. In this mode the input

buffers are TTL.

PORTE pins are multiplexed with analog inputs.

When selected as an analog input, these pins will read as '0's. TRISE controls the

direction of the RE pins, even when they are being used as analog inputs. The user

must make sure to keep the pins configured as inputs when using them as analog

inputs.

PORTE FUNCTIONS

SUMMARY OF REGISTERS ASSOCIATED WITH PORTE

\ MEMORY ORGANISATION :

There are three memory blocks in each of

the PIC16F877 MUC’s. The program memory and Data Memory have separate

buses so that concurrent access can occur.

PROGRAM MEMORY ORGANISATION :

The PIC16f877 devices have a 13-bit

program counter capable of addressing 8K *14 words of FLASH program

memory. Accessing a location above the physically implemented address will

cause a wraparound.

The RESET vector is at 0000h and the interrupt vector is at 0004h.

DATA MEMORY ORGANISTION :

The data memory is partitioned into multiple

banks which contain the General Purpose Registers and the special functions

Registers. Bits RP1 (STATUS<6) and RP0 (STATUS<5>) are the bank selected

bits.

RP1:RP0 Banks

00 0

01 1

10 2

11 3

Each bank extends up to 7Fh (1238 bytes).

The lower locations of each bank are reserved for the Special Function Registers.

Above the Special Function Registers are General Purpose Registers, implemented

as static RAM. All implemented banks contain special function registers. Some

frequently used special function registers from one bank may be mirrored in

another bank for code reduction and quicker access.

PIC16F877 REGISTER FILE MAP

GENERAL PURPOSE REGISTER FILE :

The register file can be accessed either

directly or indirectly through the File Selected Register (FSR). There are some

Special Function Registers used by the CPU and peripheral modules for controlling

the desired operation of the device. These registers are implemented as static

RAM. The Special Function Registers can be classified into two sets; core (CPU)

and peripheral. Those registers associated with the core functions.

INSTRUCTION SET SUMMARY :

Each PIC 16f877 instruction is a 14-bit

word, divided into an OPCODE which specifies the instruction type and one or

more operand which further specify the operation of the instruction. The

PIC16F877 instruction set summary in Table 2.13 lists byte-oriented, bit-

oriented, and literal and control operations. It shows the opcode Field

descriptions.

OPCODE FIELD DESCRIPTIONS

For byte-oriented instructions, ‘f’

represents a file register designator and ’d’ represents a destination designator. The

file register designator specifies which file register is to be used by the instruction.

The destination designator specified where the result of the operation is to be

placed. If ‘d’ is zero, the result is placed in the w register. If ‘d’ is one, the result is

placed in the file register specified in the instruction.

For bit-oriented instructions, ‘b’ represents

a bit field designator which selects the number of the bit affected by the operation,

which ‘f’ represents the address of the file in which the bits is located. For literal

and control operations, ‘k’ represents an eight or eleven bit constant or literal

value.

The instruction set is highly orthogonal and is grouped into three basic

categories:

• Byte-oriented operations

• Bit-oriented operations

• Literal and control operations

All instructions are executed within one

single instruction cycle, unless a conditional test is true or the program counter is

changed as a result of an instruction. In this case, the execution takes two

instruction cycles with the second cycle executed as a NOP. One instruction cycle

consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the

normal instruction execution time is 1 ms. If a conditional test is true or the

program counter is changed as a result of an instruction, then the instruction

execution time is 2 ms.

16F877 INSTRUCTION SET

GENERAL FORMAT FOR INSTRUCTIONS :

7.2.2 MICROCONTROLLER:

INTRODUCTION

Microcontrollers are destined to play an increasingly important role in

revolutionizing various industries and influencing our day to day life more strongly

than one can imagine. Since its emergence in the early 1980's the microcontroller

has been recognized as a general purpose building block for intelligent digital

systems. It is finding using diverse area, starting from simple children's toys to

highly complex spacecraft. Because of its versatility and many advantages, the

application domain has spread in all conceivable directions, making it ubiquitous.

As a consequence, it has generate a great deal of interest and enthusiasm among

students, teachers and practicing engineers, creating an acute education need for

imparting the knowledge of microcontroller based system design and development.

It identifies the vital features responsible for their tremendous impact, the acute

educational need created by them and provides a glimpse of the major application

area.

MICROCONTROLLER

A microcontroller is a complete microprocessor system built on a single IC.

Microcontrollers were developed to meet a need for microprocessors to be put into

low cost products. Building a complete microprocessor system on a single chip

substantially reduces the cost of building simple products, which use the

microprocessor's power to implement their function, because the microprocessor is

a natural way to implement many products. This means the idea of using a

microprocessor for low cost products comes up often. But the typical 8-bit

microprocessor based system, such as one using a Z80 and 8085 is expensive. Both

8085 and Z80 system need some additional circuits to make a microprocessor

system. Each part carries costs of money. Even though a product design may

requires only very simple system, the parts needed to make this system as a low

cost product.

To solve this problem microprocessor system is implemented with a single

chip microcontroller. This could be called microcomputer, as all the major parts

are in the IC. Most frequently they are called microcontroller because they are used

they are used to perform control functions.

The microcontroller contains full implementation of a standard

MICROPROCESSOR, ROM, RAM, I/0, CLOCK, TIMERS, and also SERIAL

PORTS. Microcontroller also called "system on a chip" or "single chip

microprocessor system" or "computer on a chip".

A microcontroller is a Computer-On-A-Chip, or, if you prefer, a single-chip

computer. Micro suggests that the device is small, and controller tells you that the

device' might be used to control objects, processes, or events. Another term to

describe a microcontroller is embedded controller, because the microcontroller and

its support circuits are often built into, or embedded in, the devices they control.

Today microcontrollers are very commonly used in wide variety of

intelligent products. For example most personal computers keyboards and

implemented with a microcontroller. It replaces Scanning, Debounce, Matrix

Decoding, and Serial transmission circuits. Many low cost products, such as Toys,

Electric Drills, Microwave Ovens, VCR and a host of other consumer and

industrial products are based on microcontrollers.

EVOLUTION OF MICROCONTROROLLER

Markets for microcontrollers can run into millions of units per application.

At these volumes of the microcontrollers is a commodity items and must be

optimized so that cost is at a minimum. .Semiconductor manufacturers have

produced a mind-numbing array of designs that would seem to meet almost any

need. Some of the chips listed in this sec0tion are no longer regular production,

most are current, and a few are best termed as "smoke ware": the dreams of an

aggressive marketing department.

Sl.N

o

Manufacturer Chip

Designation

Year No.

of

Pins

No

of

I/O

RAM RO

M

Other

Features

4 Bit MC

1. Texas

Instruments

TMS 1000 Mid

1970

28 23 64 1K LED

Display

2. Hitachi HMCS 40 - 28 10 32 512 10 bit

ROM

3. Toshiba TLCS 47 - 42 35 128 2K Serial bit

I/O

8 bit MC

1. Intel 8048 1976 40 27 64 1K External

Memory

8K

2 Intel 8051 1980 40 32 128 4K External

Memory

128 K

3. Motorola 6081 1977 - 31 128 2 K

4. Motorola 68HC11 1985 52 40 256 8K Serial

Port,

ADC,

5. Zilog Z8 - 40 32 128 2K External

Memory

128K,

16 Bit MC

1. Intel 80C196 - 68 40 232 8K External

Memory

64K,

Serial

Port,

ADC,

WDT,

PWM

2. Hitachi H8/532 - 84 65 1K 32K External

Memory

1M, Serial

Port,

ADC,

PWM

3. National HPC16164 - 68 52 512 16K External

Memory

64K,

ADC,

WDT,

PWM

32 Bit MC

1. Intel 80960 - 132 20 MHz clock, 32 bit bus, 512

byte instruction cache

APPLICATION

Microcontrollers did you use today?

A microcontroller is a kind of miniature computer that you can find in all

kinds of Gizmos. Some examples of common, every-day products that have

microcontrollers are built-in. If it has buttons and a digital display, chances are it

also has a programmable microcontroller brain.

Every-Day the devices used by ourselves that contain Microcontrollers. Try

to make a list and counting how many devices and the events with microcontrollers

you use in a typical day. Here are some examples: if your clock radio goes off, and

you hit the snooze button a few times in the morning, the first thing you do in your

day is interact with a microcontroller. Heating up some food in the microwave

oven and making a call on a cell phone also involve operating microcontrollers.

That's just the beginning. Here are a few more examples: Turning on the

Television with a handheld remote, playing a hand held game, Using a calculator,

and Checking your digital wrist watch. All those devices have microcontrollers

inside them, that interact with you. Consumer appliances aren't the only things that

contain microcontrollers. Robots, machinery, aerospace designs and other high-

tech devices are also built with microcontrollers.

One of the major differences between a micro controller and a microprocessor is

that a controller often deals with bits , not bytes as in the real world application, for

example switch contacts can only be open or close, indicators should be lit or dark

and motors can be either turned on or off and so forth. BLOCK AND PIN SPI

Serial Bus Interface DIAGRAM OF MICROCONTROLLER

Pin

Description

VCC

Supply voltage.

GND

Ground.

Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port each

pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be

used as high impedance inputs. Port 0 may also be configured to be the

multiplexed low order address/data bus during accesses to external program and

data memory. In this mode P0 has internal pull-ups. Port 0 also receives the code

bytes during Flash programming, and outputs the code bytes during program

verification. External pull-ups are required during program verification.

Port 1

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port

1 output buffers can sink/source four TTL inputs. When 1s are written to

Port 1 pins they are pulled high by the internal pull-ups and can be used as

inputs. As inputs, Port 1 pins that are externally being pulled low will source

current (IIL) because of the internal pull-ups. Port 1 also receives the low-

order address bytes during Flash programming and verification.

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port

2 output buffers can sink/source four TTL inputs. When 1s are written to

Port 2 pins they are pulled high by the internal pull-ups and can be used as

inputs. As inputs, Port 2 pins that are externally being pulled low will source

current (IIL) because of the internal pull-ups. Port 2 emits the high-order

address byte during fetches from external program memory and during

accesses to external data memory that use 16-bit addresses (MOVX @

DPTR). In this application it uses strong internal pull-ups when emitting 1s.

During accesses to external data memory that use 8-bit addresses (MOVX @

RI), Port 2 emits the contents of the P2 Special Function Register. Port 2

also receives the high-order address bits and some control signals during

Flash programming and verification.

Port 3

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port

3 output buffers can sink/source four TTL inputs. When 1s are written to

Port 3 pins they are pulled high by the internal pull-ups and can be used as

inputs. As inputs, Port 3 pins that are externally being pulled low will source

current (IIL) because of the pull-ups. Port 3 also serves the functions of

various special features of the AT89C51 as listed below:

Port 3 also receives some control signals for Flash programming and

verification.

RST

Reset input. A high on this pin for two machine cycles while the

oscillator is running resets the device.

ALE/PROG

Address Latch Enable output pulse for latching the low byte of the

address during accesses to external memory. This pin is also the program

pulse input (PROG) during Flash programming. In normal operation ALE is

emitted at a constant rate of 1/6 the oscillator frequency, and may be used

for external timing or clocking purposes. Note, however, that one ALE pulse

is skipped during each access to external Data Memory.

If desired, ALE operation can be disabled by setting bit 0 of SFR

location 8EH. With the bit set, ALE is active only during a MOVX or

MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the

ALE-disable bit has no effect if the microcontroller is in external execution

mode.

PSEN

Program Store Enable is the read strobe to external program memory.

When the AT89C51 is executing code from external program memory,

PSEN is activated twice each machine cycle, except that two PSEN

activations are skipped during each access to external data memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to

enable the device to fetch code from external program memory locations

starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is

programmed, EA will be internally latched on reset. EA should be strapped

to VCC for internal program executions.

This pin also receives the 12-volt programming enable voltage (VPP)

during Flash programming, for parts that require 12-volt VPP.

XTAL1

Input to the inverting oscillator amplifier and input to the internal

clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier. It should be noted that

when idle is terminated by a hard ware reset, the device normally resumes

program execution, from where it left off, up to two machine cycles before

the internal reset algorithm takes control. On-chip hardware inhibits access

to internal RAM in this event, but access to the port pins is not inhibited. To

eliminate the possibility of an unexpected write to a port pin when Idle is

terminated by reset, the instruction following the one that invokes Idle

should not be one that writes to a port pin or to external memory.

Architecture of 89C51

ADVANTAGES OF MICROCONTROLLERS:

1. If a system is developed with a microprocessor, the designer

has to go for external memory such as RAM, ROM or EPROM and

peripherals and hence the size of the PCB will be large enough to hold all

the required peripherals. But, the micro controller has got all these peripheral

facilities on a single chip so development of a similar system with a micro

controller reduces PCB size and cost of the design.

INTRODUCTION TO ATMEL MICROCONTROLLER

SERIES: 89C51 Family, TECHNOLOGY: CMOS

The major Features of 8-bit Micro controller ATMEL 89C51:

8 Bit CPU optimized for control applications

Extensive Boolean processing (Single - bit Logic ) Capabilities.

On - Chip Flash Program Memory

On - Chip Data RAM

Bi-directional and Individually Addressable I/O Lines

Multiple 16-Bit Timer/Counters

Full Duplex UART

Multiple Source / Vector / Priority Interrupt Structure

On - Chip Oscillator and Clock circuitry.

On - Chip EEPROM

Watch Dog Timer

POWER MODES OF ATMEL 89C51 ICROCONTROLLER:

To exploit the power savings available in CMOS circuitry. Atmel ’s Flash

micro controllers have two software-invited reduced power modes.

IDLE MODE:

The CPU is turned off while the RAM and other on - chip peripherals

continue operating. Inn this mode current draw is reduced to about 15 percent of

the current drawn when the device is fully active.

POWER DOWN MODE:

All on-chip activities are suspended while the on – chip RAM continues to

hold its data. In this mode, the device typically draws less than 15 Micro Amps and

can be as low as 0.6 Micro Amps

POWER ON RESET:

When power is turned on, the circuit holds the RST pin high for an amount

of time that depends on the capacitor value and the rate at which it charges.

To ensure a valid reset, the RST pin must be held high long enough to allow

the oscillator to start up plus two machine cycles. On power up, VCC should rise

within approximately 10ms. The oscillator start-up time depends on the oscillator

frequency. For a 10 MHz crystal, the start-up time is typically 1ms.With the given

circuit, reducing VCC quickly to 0 causes the RST pin voltage to momentarily fall

below 0V. How ever, this voltage is internally l limited and will not harm the

device.

MEMORY ORGANIZATION:

* Logical Separation of Program and Data Memory *

All Atmel Flash micro controllers have separate address spaces for program

and data memory as shown in Fig 1.The logical separation of program and data

memory allows the data memory to be accessed by 8 bit addresses . Which can be

more quickly stored and manipulated by an 8 bit CPU Nevertheless 16 Bit data

memory addresses can also be generated through the DPTR register.

Program memory can only be read. There can be up to 64K bytes of directly

addressable program memory. The read strobe for external program memory is the

Program Store Enable Signal (PSEN) Data memory occupies a separate address

space from program memory. Up to 64K bytes of external memory can be

directly addressed in the external data memory space. The CPU generates read and

write signals, RD and WR, during external data memory accesses. External

program memory and external data memory can be combined by an applying the

RD and PSEN signals to the inputs of AND gate and using the output of the fate as

the read strobe to the external program/data memory.

PROGRAM MEMORY:

The map of the lower part of the program memory, after reset, the CPU

begins execution from location 0000h. Each interrupt is assigned a fixed location

in program memory. The interrupt causes the CPU to jump to that location, where

it executes the service routine. External Interrupt 0 for example, is assigned to

location 0003h. If external Interrupt 0 is used, its service routine must begin at

location 0003h. If the I interrupt in not used its service location is available as

general-purpose program memory.

The interrupt service locations are spaced at 8 byte intervals 0003h for

External interrupt 0, 000Bh for Timer 0, 0013h for External interrupt 1,001Bh for

Timer1, and so on. If an Interrupt service routine is short enough (as is often the

case in control applications) it can reside entirely within that 8-byte interval.

Longer service routines can use a jump instruction to skip over subsequent

interrupt locations. If other interrupts are in use. The lowest addresses of program

memory can be either in the on-chip Flash or in an external memory. To make this

selection, strap the External Access (EA) pin to either VCC or GND. For example,

in the AT89C51 with 4K bytes of on-chip Flash, if the EA pin is strapped to VCC,

program fetches to addresses 0000h through 0FFFh are directed to internal Flash.

Program fetches to addresses 1000h through FFFFh are directed to external

memory.

DATA MEMORY:

The Internal Data memory is dived into three blocks namely, Refer Fig

The lower 128 Bytes of Internal RAM.

The Upper 128 Bytes of Internal RAM.

Special Function Register

Internal Data memory Addresses are always 1 byte wide, which implies an

address space of only 256 bytes. However, the addressing modes for internal RAM

can in fact accommodate 384 bytes. Direct addresses higher than 7Fh access one

memory space, and indirect addresses higher than 7Fh access a different Memory

Space.

The lowest 32 bytes are grouped into 4 banks of 8 registers. Program

instructions call out these registers as R0 through R7. Two bits in the Program

Status Word (PSW) Select, which register bank, is in use. This architecture allows

more efficient use of code space, since register instructions are shorter than

instructions that use direct addressing.

The next 16-bytes above the register banks form a block of bit addressable

memory space. The micro controller instruction set includes a wide selection of

single - bit instructions and this instruction can directly address the 128 bytes in

this area. These bit addresses are 00h through 7Fh. either direct or indirect

addressing can access all of the bytes in lower 128 bytes. Indirect addressing can

only access the upper 128. The upper 128 bytes of RAM are only in the devices

with 256 bytes of RAM.

The Special Function Register includes Ports latches, timers, peripheral

controls etc., direct addressing can only access these register. In general, all Atmel

micro controllers have the same SFRs at the same addresses in SFR space as the

AT89C51 and other compatible micro controllers. However, upgrades to the

AT89C51 have additional SFRs. Sixteen addresses in SFR space are both byte and

bit Addressable. The bit Addressable SFRs are those whose address ends in 000B.

The bit addresses in this area are 80h through FFh.

ADDRESSING MODES:

DIRECT ADDRESSING:

In direct addressing, the operand specified by an 8-bit address field in the

instruction. Only internal data RAM and SFR’s can be directly addressed.

INDIRECT ADDRESSING:

In Indirect addressing, the instruction specifies a register that contains the

address of the operand. Both internal and external RAM can indirectly address.

The address register for 8-bit addresses can be either the Stack Pointer or R0

or R1 of the selected register Bank. The address register for 16-bit addresses can be

only the 16-bit data pointer register, DPTR.

INDEXED ADDRESSING:

Program memory can only be accessed via indexed addressing this

addressing mode is intended for reading look-up tables in program memory. A 16

bit base register (Either DPTR or the Program Counter) points to the base of the

table, and the accumulator is set up with the table entry number. Adding the

Accumulator data to the base pointer forms the address of the table entry in

program memory.

Another type of indexed addressing is used in the“ case jump ” instructions.

In this case the destination address of a jump instruction is computed as the sum of

the base pointer and the Accumulator data.

REGISTER INSTRUCTION:

The register banks, which contains registers R0 through R7, can be accessed

by instructions whose opcodes carry a 3-bit register specification. Instructions

that access the registers this way make efficient use of code, since this mode

eliminates an address byte. When the instruction is executed, one of four banks is

selected at execution time by the row bank select bits in PSW.

REGISTER - SPECIFIC INSTRUCTION:

Some Instructions are specific to a certain register. For example some

instruction always operates on the Accumulator, so no address byte is needed to

point OT ir. In these cases, the opcode itself points to the correct register.

Instruction that register to Accumulator as A assemble as Accumulator - specific

Opcodes.

IMMEDIATE CONSTANTS:

The value of a constant can follow the opcode in program memory For

example. MOV A, #100 loads the Accumulator with the decimal number 100. The

same number could be specified in hex digit as 64h.

PROGRAM STATUS WORD:

Program Status Word Register in Atmel Flash Micro controller:

CY AC F0 RS1 RS0 OV --- P

PSW 7 PSW 0

PSW 6 PSW 1

PSW 5 PSW 2

PSW 4 PSW 3

PSW 0:

Parity of Accumulator Set By Hardware To 1 if it contains an Odd number

of 1s, Otherwise it is reset to 0.

PSW1:

User Definable Flag

PSW2:

Overflow Flag Set By Arithmetic Operations

PSW3:

Register Bank Select

1.1 PSW4:

1.2 Register Bank Select

PSW5:

General Purpose Flag.

PSW6:

Auxiliary Carry Flag Receives Carry Out from

Bit 1 of Addition Operands

PSW7:

Carry Flag Receives Carry Out From Bit 1 of ALU Operands.

The Program Status Word contains Status bits that reflect the current sate of

the CPU. The PSW shown if Fig resides in SFR space. The PSW contains the

Carry Bit, The auxiliary Carry (For BCD Operations) the two - register bank select

bits, the Overflow flag, a Parity bit and two user Definable status Flags.

The Carry Bit, in addition to serving as a Carry bit in arithmetic operations

also serves the as the “Accumulator” for a number of Boolean Operations .The bits

RS0 and RS1 select one of the four register banks. A number of instructions

register to these RAM locations as R0 through R7.The status of the RS0 and

RS1 bits at execution time determines which of the four banks is selected.

The Parity bit reflect the Number of 1s in the Accumulator .P=1 if the

Accumulator contains an even number of 1s, and P=0 if the Accumulator contains

an even number of 1s. Thus, the number of 1s in the Accumulator plus P is always

even. Two bits in the PSW are uncommitted and can be used as general-purpose

status flags.

INTERRUPTS

The AT89C51 provides 5 interrupt sources: Two External interrupts, two-

timer interrupts and a serial port interrupts. The External Interrupts INT0 and INT1

can each either level activated or transistion - activated, depending on bits IT0 and

IT1 in Register TCON. The Flags that actually generate these interrupts are the IE0

and IE1 bits in TCON. When the service routine is vectored to hardware clears the

flag that generated an external interrupt only if the interrupt WA transition -

activated. If the interrupt was level - activated, then the external requesting source

(rather than the on-chip hardware) controls the requested flag. Tf0 and Tf1

generate the Timer 0 and Timer 1 Interrupts, which are set by a rollover in their

respective Timer/Counter Register (except for Timer 0 in Mode 3). When a timer

interrupt is generated, the on-chip hardware clears the flag that generated it when

the service routine is vectored to. The logical OR of RI and TI generate the Serial

Port Interrupt. Neither of these flag is cleared by hardware when the service

routine is vectored to. In fact, the service routine normally must determine whether

RI or TI generated the interrupt an the bit must be cleared in software.

In the Serial Port Interrupt is generated by the logical OR of RI and TI.

Neither of these flag is cleared by hardware when the service routine is vectored to.

In fact, the service routine normally must determine whether RI to TI generated the

interrupt and the bit must be cleared in software.

IE: Interrupt Enable Register

EA - ET2 ES ET1 EX1 ET0 EX0

Enable bit = 1 enabled the interrupt

Enable bit = 0 disables it.

Symbol Position Function

EA IE. Global enable / disable all interrupts.

If EA = 0, no interrupt will be

Acknowledge.

If EA = 1, each interrupt source is

individually enabled to disabled by

setting or clearing its

enable bit

- IE.6 Undefined / reserved

ET2 IE.5 Timer 2 Interrupt enable Bit

ES IE.4 Serial Port Interrupt enabled bit.

ET1 IE.3 Timer 1 Interrupt enable bit.

EX1 IE.2 External Interrupt 1 enable bit.

ET0 IE.1 Timer 0 Interrupt enable bit.

EX0 IE.0 External Interrupt 0 enable bit.

OSCILLATOR AND CLOCK CIRCUIT:

XTAL1 and XTAL2 are the input and output respectively of an inverting

amplifier which is intended for use as a crystal oscillator in the pierce

configuration, in the frequency range of 1.2 MHz to 12 MHz. XTAL2 also the input

to the internal clock generator.

To drive the chip with an internal oscillator, one would ground XTAL1 and

XTAL2. Since the input to the clock generator is divide by two flip flop there are

no requirements on the duty cycle of the external oscillator signal. However,

minimum high and low times must be observed.

The clock generator divides the oscillator frequency by 2 and provides a tow

phase clock signal to the chip. The phase 1 signal is active during the first half to

each clock period and the phase 2 signals are active during the second half of each

clock period.

CPU TIMING:

A machine cycle consists of 6 states. Each stare is divided into a phase /

half, during which the phase 1 clock is active and phase 2 half. Arithmetic and

Logical operations take place during phase1 and internal register - to register

transfer take place during phase 2

Trends and developments in micro controller

The manner in which the use of micro controllers is shaping our lives is breathtaking. Today, this versatile device can be found in a variety of control

applications. CVTs, VCRs, CD players, microwave ovens, and automotive engine systems are some of these.

A micro controller unit (MCU) uses the microprocessor as its central processing unit (CPU) and incorporates memory, timing reference, I/O peripherals, etc on the same chip. Limited computational capabilities and enhanced I/O are special features.

The micro controller is the most essential IC for continuous process- based applications in industries like chemical, refinery, pharmaceutical automobile, steel, and electrical, employing programmable logic systems (DCS). PLC and DCS thrive on the programmability of an MCU.

There are many MCU manufacturers. To understand and apply general concepts, it is necessary to study one type in detail. This specific knowledge can be used to understand similar features of other MCUs.

Micro controller devices have many similarities. When you look at the differences, they are not so great either. Most common and popular MCUs are considered to be mature and well-established products, which have their individual adherents and devotees. There are a number of variants within each family to satisfy most memory, I/O, data conversion, and timing needs of end-user applications.

The MCU is designed to operate on application-oriented sensor data-for example, temperature and pressure of a blast furnace in an industrial process that is fed through its serial or operated on under the control of software and stored in ROM. Appropriate signals are fed via output ports to control external devices and systems.

Applications of Microcontrollers

Microcontrollers are designed for use in sophisticated real time applications

such as

1. Industrial Control

2. Instrumentation and

3. Intelligent computer peripherals

They are used in industrial applications to control

Motor

Robotics

Discrete and continuous process control

In missile guidance and control

In medical instrumentation

Oscilloscopes

Telecommunication

Automobiles

For Scanning a keyboard

Driving an LCD

For Frequency measurements

Period Measurements

7.2.3 LCD DISPLAY

INTRODUCTION:

Liquid crystal displays (LCDs) have materials which combine the properties

of both liquids and crystals. Rather than having a melting point, they have a

temperature range within which the molecules are almost as mobile as they would

be in a liquid, but are grouped together in an ordered form similar to a crystal.

An LCD consists of two glass panels, with the liquid crystal material sand

witched in between them. The inner surface of the glass plates are coated with

transparent electrodes which define the character, symbols or patterns to be

displayed polymeric layers are present in between the electrodes and the liquid

crystal, which makes the liquid crystal molecules to maintain a defined orientation

angle.

One each polarisers are pasted outside the two glass panels. These polarisers

would rotate the light rays passing through them to a definite angle, in a particular

direction

When the LCD is in the off state, light rays are rotated by the two polarisers

and the liquid crystal, such that the light rays come out of the LCD without any

orientation, and hence the LCD appears transparent. When sufficient voltage

is applied to the electrodes, the liquid crystal molecules would be aligned in a

specific direction. The light rays passing through the LCD would be rotated by the

polarisers, which would result in activating / highlighting the desired characters.

The LCD’s are lightweight with only a few millimeters thickness. Since the

LCD’s consume less power, they are compatible with low power electronic

circuits, and can be powered for long durations. The LCD’s don’t generate light

and so light is needed to read the display. By using backlighting, reading is

possible in the dark. The LCD’s have long life and a wide operating temperature

range.Changing the display size or the layout size is relatively simple which makes

the LCD’s more customer friendly. The LCDs used exclusively in watches,

calculators and measuring instruments are the simple seven-segment displays,

having a limited amount of numeric data. The recent advances in technology have

resulted in better legibility, more information displaying capability and a wider

temperature range. These have resulted in the LCDs being extensively used in

telecommunications and entertainment electronics. The LCDs have even started

replacing the cathode ray tubes (CRTs) used for the display of text and graphics,

and also in small TV applications.

POWER SUPPLY:

The power supply should be of +5V, with maximum allowable transients of

10mv. To achieve a better / suitable contrast for the display, the voltage (VL) at pin

3 should be adjusted properly.

A module should not be inserted or removed from a live circuit. The ground

terminal of the power supply must be isolated properly so that no voltage is

induced in it. The module should be isolated from the other circuits, so that stray

voltages are not induced, which could cause a flickering display.

HARDWARE:

Develop a uniquely decoded ‘E’ strobe pulse, active high, to accompany

each module transaction. Address or control lines can be assigned to drive the RS

and R/W inputs.

Utilize the Host’s extended timing mode, if available, when transacting with

the module. Use instructions, which prolong the Read and Write or other

appropriate data strobes, so as to realize the interface timing requirements.

If a parallel port is used to drive the RS, R/W and ‘E’ control lines, setting

the ‘E’ bit simultaneously with RS and R/W would violate the module’s set up

time. A separate instruction should be used to achieve proper interfacing timing

requirements.

MOUNTING:

Cover the display surface with a transparent protective plate, to protect the

polarizer. Don’t touch the display surface with bare hands or any hard materials.

This will stain the display area and degrade the insulation between terminals.Do

not use organic solvents to clean the display panel as these may advesely affect

tape or with absorbant cotton and petroleum benzene. The processing or even a

slight deformation of the claws of the metal frame will have effect on the

connection of the output signal and cause an abnormal display. Do not damage or

modify the pattern wiring, or drill attachment holes in the PCB. When assembling

the module into another equipment, the space between the module and the fitting

plate should have enough height, to avoid causing stress to the module surface.

Make sure that there is enough space behind the module, to dissipate the

heat generated by the ICs while functioning for longer durations.

When an electrically powered screwdriver is used to install the module,

ground it properly. While cleaning by a vacuum cleaner, do not bring the sucking

mouth near the module. Static electricity of the electrically powered driver or the

vacuum cleaner may destroy the module.

ENVIRONMENTAL PRECAUTIONS:

Operate the LCD module under the relative condition of 40C and 50%

relative humidity. Lower temperature can cause retardation of the blinking speed

of the display, while higher temperature makes the overall display discolor. When

the temperature gets to be within the normal limits, the display will be normal.

Polarization degradation, bubble generation or polarizer peel-off may occur with

high temperature and humidity. Contact with water or oil over a long period of

time may cause deformation or colour fading of the display. Condensation on the

terminals can cause electro-chemical reaction disrupting the terminal circuit.

TROUBLE SHOOTING

INTRODUCTION:

When the power supply is given to the module, with the pin 3 (VL)

connected to ground, all the pixels of a character gets activated in the following

manner: All the characters of a single line display, as in CDM 16108. The

first eight characters of a single line display, operated in the two-line display mode,

as in CDM 16116.

The first line of characters of a two-line display as in CDM 16216 and

40216. The first and third line of characters of a four-line display operated in the

two-line display mode, as in CDM 20416. If the above mentioned does not

occur, the module should be initialized by software. Make sure that the

control signals ‘E’ , R/W and RS are according to the interface timing

requirements.

IMPROPER CHARACTER DISPLAY:

When the characters to be displayed are missing between, the data read/write

is too fast. A slower interfacing frequency would rectify the problem. When

uncertainty is there in the start of the first characters other than the specified ones

are rewritten, check the initialization and the software routine. In a multi-line

display, if the display of characters in the subsequent lines does’nt take place

properly, check the DD RAM addresses set for the corresponding display lines.

When it is unable to display data, even though it is present in the DD RAM,

either the display on/off flag is in the off state or the display shift function is not set

properly. When the display shift is done simultaneous with the data writa

operation, the data may not be visible on the display. If a character not found

in the font table is displayed, or a character is missing, the CG ROM is faulty and

the controller IC have to be changed If particular pixels of the characters are

missing, or not getting activated properly, there could be an assembling problem in

the module. In case any other problems are encountered you could send the

module to our factory for testing and evaluation.

1.2.1 CRYSTALONICS DISPLAY

INTRODUCTION:

Crystalonics dot –matrix (alphanumeric) liquid crystal displays are available

in TN, STN types, with or without backlight. The use of C-MOS LCD controller

and driver ICs result in low power consumption. These modules can be interfaced

with a 4-bit or 8-bit micro processor /Micro controller.

The built-in controller IC has the following features:

Correspond to high speed MPU interface (2MHz)

80 x 8 bit display RAM (80 Characters max)

9,920 bit character generator ROM for a total of 240 character fonts. 208

character fonts (5 x 8 dots) 32 character fonts (5 x 10 dots)

64 x 8 bit character generator RAM 8 character generator RAM 8 character

fonts (5 x 8 dots) 4 characters fonts (5 x 10 dots)

Programmable duty cycles

1/8 – for one line of 5 x 8 dots with cursor

1/11 – for one line of 5 x 10 dots with cursor

1/16 – for one line of 5 x 8 dots with cursor

Wide range of instruction functions display clear, cursor home, display

on/off, cursor on/off, display character blink, cursor shift, display shift.

Automatic reset circuit, that initializes the controller / driver ICs after power

on.

BUSY FLAG:

When the busy flag is1, the controller is in the internal operation mode, and

the next instruction will not be accepted.

When RS = 0 and R/W = 1, the busy flag is output to DB7.

The next instruction must be written after ensuring that the busy flag is 0.

ADDRESS COUNTER:

The address counter allocates the address for the DD RAM and CG RAM

read/write operation when the instruction code for DD RAM address or CG RAM

address setting, is input to IR, the address code is transferred from IR to the

address counter. After writing/reading the display data to/from the DD RAM or

CG RAM, the address counter increments/decrements by one the address, as an

internal operation. The data of the address counter is output to DB0 to DB6 while

R/W = 1 and RS = 0.

DISPLAY DATA RAM (DD RAM)

The characters to be displayed are written into the display data RAM (DD

RAM), in the form of 8 bit character codes present in the character font table. The

extended capacity of the DD RAM is 80 x 8 bits i.e. 80 characters.

CHARATCER GENERATOR ROM (CG ROM)

The character generator ROM generates 5 x 8 dot 5 x 10 dot character patterns

from 8 bit character codes. It generates 208, 5 x 8 dot character patterns and 32, 5 x

10 dot character patterns.

CHARACTER GENERATOR RAM (CG RAM)

In the character generator RAM, the user can rewrite character patterns by

program. For 5 x 8 dots, eight character patterns can be written, and for 5 x 10

dots, four character patterns can be written.

INTERFACING THE MICROPROCESSOR CONTROLLER:

The module, interfaced to the system, can be treated as RAM input/output,

expanded or parallel I/O.Since there is no conventional chip select signal,

developing a strobe signal for the enable signal (E) and applying appropriate

signals to the register select (RS) and read/write (R/W) signals are important.The

module is selected by gating a decoded module – address with the host –

processor’s read/write strobe. The resultant signal, applied to the LCDs enable (E)

input, clocks in the data.The ‘E’ signal must be a positive going digital strobe,

which is active while data and control information are stable and true. The falling

edge of the enable signal enables the data / instruction register of the controller.

All module timings are referenced to specific edges of the ‘E’ signal. The ‘E’

signal is applied only when a specific module transaction is desired.The read and

write strobes of the host, which provides the ‘E’ signals, should not be linked to the

module’s R/W line. An address bit which sets up earlier in the host’s machine

cycle can be used as R/W.When the host processor is so fast that the strobes are too

narrow to serve as the ‘E’ pulse

a. Prolong these pulses by using the hosts ‘Ready’ input

b. Prolong the host by adding wait states

c. Decrease the Hosts Crystal frequency.

Inspite of doing the above mentioned, if the problem continues, latch both the data

and control information and then activate the ‘E’ signal

When the controller is performing an internal operation he busy flag (BF) will set

and will not accept any instruction. The user should check the busy flag or should

provide a delay of approximately 2ms after each instruction.The module presents

no difficulties while interfacing slower MPUs.The liquid crystal display module

can be interfaced, either to 4-bit or 8-bit MPUs.

For 4-bit data interface, the bus lines DB4 to DB7 are used for data transfer, while

DB0 to DB3 lines are disabled. The data transfer is complete when the 4-bit data

has been transferred twice.

The busy flag must be checked after the 4-bit data has been transferred twice. Two

more 4-bit operations then transfer the busy flag and address counter data.For 8-bit

data interface, all eight-bus lines (DB0 to DB7) are used.

A liquid crystal display (LCD) is a thin, flat electronic visual display that uses the light modulating properties of liquid crystals (LCs). LCs do not emit light directly.

They are used in a wide range of applications including: computer monitors,

television, instrument panels, aircraft cockpit displays, signage, etc. They are

common in consumer devices such as video players, gaming devices, clocks,

watches, calculators, and telephones. LCDs have displaced cathode ray tube(CRT)

displays in most applications. They are usually more compact, lightweight,

portable, less expensive, more reliable, and easier on the eyes. They are available

in a wider range of screen sizes than CRT and plasma displays, and since they do

not use phosphors, they cannot suffer image burn-in.LCDs are more energy

efficient and offer safer disposal than CRTs. Its low electrical power consumption

enables it to be used in battery-powered electronic equipment. It is an

electronically-modulated optical device made up of any number of pixels filled

with liquid crystals and arrayed in front of a light source (backlight) or reflector to

produce images in colour or monochrome. The earliest discovery leading to the

development of LCD technology, the discovery of liquid crystals, dates from 1888.

By 2008, worldwide sales of televisions with LCD screens had surpassed the sale

of CRT units

7.2.4 VIBRATION SENSOR:

A piezoelectric sensor is a device that uses the piezoelectric effect to measure

pressure, acceleration, strain or force by converting them to an electrical signal.

Electrical properties

Schematic symbol and electronic model of a piezoelectric sensor

A piezoelectric transducer has very high DC output impedance and can be modeled

as a proportional voltage source and filter network. The voltage V at the source is

directly proportional to the applied force, pressure, or strain.[2] The output signal is

then related to this mechanical force as if it had passed through the equivalent

circuit.

Frequency response of a piezoelectric sensor; output voltage vs applied force

A detailed model includes the effects of the sensor's mechanical construction and

other non-idealities.[3] The inductance Lm is due to the seismic mass and inertia of

the sensor itself. Ce is inversely proportional to the mechanical elasticity of the

sensor. C0 represents the static capacitance of the transducer, resulting from an

inertial mass of infinite size.[3] Ri is the insulation leakage resistance of the

transducer element. If the sensor is connected to a load resistance, this also acts in

parallel with the insulation resistance, both increasing the high-pass cutoff

frequency.

In the flat region, the sensor can be modeled as a voltage source in series with the

sensor's capacitance or a charge source in parallel with the capacitance

For use as a sensor, the flat region of the frequency response plot is typically used,

between the high-pass cutoff and the resonant peak. The load and leakage

resistance need to be large enough that low frequencies of interest are not lost. A

simplified equivalent circuit model can be used in this region, in which Cs

represents the capacitance of the sensor surface itself, determined by the standard

formula for capacitance of parallel plates.[3][4] It can also be modeled as a charge

source in parallel with the source capacitance, with the charge directly proportional

to the applied force, as above.[2]

1.1

1.2 Sensing materials

Two main groups of materials are used for piezoelectric sensors: piezoelectric

ceramics and single crystal materials. The ceramic materials (such as PZT ceramic)

have a piezoelectric constant / sensitivity that is roughly two orders of magnitude

higher than those of single crystal materials and can be produced by inexpensive

sintering processes. The piezoeffect in piezoceramics is "trained", so unfortunately

their high sensitivity degrades over time. The degradation is highly correlated with

temperature. The less sensitive crystal materials (gallium phosphate, quartz,

tourmaline) have a much higher – when carefully handled, almost infinite – long

term stability.

7.2.5 AMPLIFIER:

An ELECTRONIC AMPLIFIER is a device for increasing the power of a signal.

It does this by taking energy from a power supply and controlling the output to

match the input signal shape but with a larger amplitude. In this sense, an amplifier

may be considered as modulating the output of the power supply.

Here we use inverting amplifier as a gain amplifier. We can change the gain by

adjusting the value of feedback resistance value.

As the open loop DC gain of an operational amplifier is extremely high we can

afford to lose some of this gain by connecting a suitable resistor across the

amplifier from the output terminal back to the inverting input terminal to both

reduce and control the overall gain of the amplifier. This then produces and effect

known commonly as Negative Feedback, and thus produces a very stable

Operational Amplifier system.

Negative Feedback is the process of "feeding back" some of the output signal

back to the input, but to make the feedback negative we must feed it back to the

"Negative input" terminal using an external Feedback Resistor called Rf. This

feedback connection between the output and the inverting input terminal produces

a closed loop circuit to the amplifier resulting in the gain of the amplifier now

being called its Closed-loop Gain.

7.2.6 KEY

A key is an instrument that is used to operate a lock. A typical key consists

of two parts: the blade, which slides into the keyway of the lock and distinguishes

between different keys, and the bow, which is left protruding so that torque can be

applied by the user. The blade is usually intended to operate one specific lock or a

small number of locks that are keyed alike.

Keys provide an inexpensive, though imperfect, method of access control for

access to properties like buildings and vehicles. As such, keys are an essential

feature of modern living in the developed world, and are common around the

globe. It is common for people to carry the set of keys they need for their daily

activities around with them, often linked by a keyring adorned by key fobs and

known as a keychain.

Types of keys

House keys

A house key is the most common sort of key. There are two main forms. The older

form is for lever locks, where a pack of flat levers (typically between two and five)

are raised to different heights by the key whereupon the slots or gates of the levers

line up and permit a bolt to move back and forth, opening or closing the lock. The

teeth or bittings of the key have flat tops rather than being pointed. Lever lock keys

tend to be bigger and less convenient for carrying, although lever locks tend to be

more secure. These are still common in many European countries.

The more recent form of house key is that for a pin-tumbler or wafer-tumbler lock.

When held upright as if to open a door, a series of grooves on either side of the key

(the key's blade) limits the type of lock the key can slide into. As the key slides

into the lock, the grooves on the blade of the key align with the wards in the

keyway allowing or denying entry to the cylinder. Then, a series of pointed teeth

and notches on the blade called bittings allow pins or wafers to move up and down

until they are in line with the shear line of the inner and outer cylinder, allowing

the cylinder or cam to rotate freely inside the lock and the lock to open. These are

predominate in the United States of America.[1]

Car key

Car key in ignition.

Car ignition and steering wheel lock

Main article: Power door locks

A car key or an automobile key is a key used to open and/or start an automobile.

Modern key designs are usually symmetrical, and some use grooves on both sides,

rather than a cut edge, to actuate the lock. It has multiple uses for the automobile

with which it was sold. A car key can open the doors, as well as start the ignition,

open the glove compartment and also open the trunk (boot) of the car. Some cars

come with an additional key known as a valet key that starts the ignition and opens

the drivers side door, but prevents the valet from gaining access to valuables that

are located in the trunk or the glove box. Some valet keys, particularly those to

high-performance vehicles, go so far as to restrict the engine's power output to

prevent joyriding.[2] Recently, features such as coded immobilizers have been

implemented in newer vehicles. More sophisticated systems make ignition

dependent on electronic devices, rather than the mechanical keyswitch.

Ignition switches/locks are combined with security locking of the steering column

(in many modern vehicles) or the gear lever (such as in Saab Automobile vehicles).

In the latter, the switch is between the seats, preventing damage to the driver's knee

in the event of a collision.

Keyless entry systems, which use either a door-mounted keypad or a remote

control in place of a car key, are becoming a standard feature on many new cars.

Some of them are handsfree.

Some high tech automotive keys are billed as theft deterrents. Mercedes-Benz uses

a key that, rather than have a cut metal piece to start the car, uses an encoded

infrared beam that communicates with the car's computer. If the codes match, the

car can be started. These keys can be expensive to replace, if lost, and can cost up

to US$400. Some car manufacturers like Land Rover and Volkswagen use a

'switchblade' key where the key is spring-loaded out of the fob when a button is

pressed. This eliminates the need for a separate key fob. This type of key has also

been known to be confiscated by airport security officials.[3]

A switchblade key is basically the same as any other car key. The only difference

is its appearance. The switchblade key is designed to fold away inside the fob

when it is not being used. To release the key from the fob you simply push a button

on the side of your fob that triggers the keys release. Switchblade keys have

become very popular recently because of their smart compact look.

Because switchblade keys are only developed for new car models they are usually

equipped with a programmed transponder chip.

Master key

A master key is intended to operate a set of several locks. Usually, there is nothing

special about the key itself, but rather the locks into which it will fit. These locks

also have keys that are specific to each one (the change key) and cannot operate

any of the others in the set. Locks that have master keys have a second set of the

mechanism used to operate them that is identical to all of the others in the set of

locks. For example, master keyed pin tumbler locks will have two shear points at

each pin position, one for the change key and one for the master key. A far more

secure (and more expensive) system has two cylinders in each lock, one for the

change key and one for the master key.

Larger organizations, with more complex "grandmaster key" systems, may have

several masterkey systems where the top level grandmaster key works in all of the

locks in the system.

A practical attack exists to create a working master key for an entire system given

only access to a single master-keyed lock, its associated change key, a supply of

appropriate key blanks, and the ability to cut new keys. This is described in

Cryptology and Physical Security: Rights Amplification in Master-Keyed

Mechanical Locks.

Locksmiths may also determine cuts for a replacement master key, when given

several different key examples from a given system.

Control key

A control key is a special key used in removable core locking systems. The control

key enables a user with very little skill to remove from the cylinder, quickly and

easily, a core with a specific combination and replace it with a core with a different

combination. In Small Format Interchangeable Cores (SFIC), similar to those

developed by Frank Best of the Best Lock Corporation, the key operates a separate

shear line, located above the operating key shear line. In Large Format Removable

Cores (LFRC), the key may operate a separate shear line or the key may work like

a master key along the operating shear line and also contact a separate locking pin

that holds the core in the cylinder. SFIC's are interchangeable from one brand to

another, while LFRC's are not.

Transponder key

Transponder keys may also be called “chip keys”. Transponder keys are

automotive ignition keys with signal-emitting circuits built inside.

When the key is turned in the ignition cylinder, the car's computer transmits a radio

signal to the transponder circuit. The circuit has no battery; it is energized by the

radio signal itself. The circuit typically has a computer chip that is programmed to

respond by sending a coded signal back to the car's computer. If the circuit does

not respond or if the code is incorrect, the engine will not start. Many cars

immobilize if the wrong key is used by intruders. Chip Keys successfully protect

cars from theft in two ways: forcing the ignition cylinder won't start the car, and

the keys are difficult to duplicate. This is why chip keys are popular in modern cars

and help decrease car theft.

Many people who have transponder keys are not aware of the fact because the

circuit is hidden inside the plastic head of the key. On the other hand, General

Motors produced what are known as VATS keys (Vehicle Anti-Theft System)

during the 1990s, which are often erroneously believed to be transponders but

actually use a simple resistor, which is visible in the blade of the key. If the value

of the resistor is wrong, or the key is a normal key without a resistor, the circuit of

the car's electrical system will not allow the engine to be started.

Double-sided key

SentrySafe four-sided key

A double-sided key is very similar to a house or car key with the exception that it

has two sets of teeth, an upper level standard set of teeth and a lower, less defined

set of teeth beside it. This makes the double-sided key's profile and its

corresponding lock look very similar to a standard key while making the attempt to

pick the lock more difficult.

Four-sided key

A four-sided key (also known a cross or cruciform key) has four sides, making it

not only harder to duplicate and the lock harder to pick, but it is also physically

more durable.

Paracentric key

A paracentric key is designed to open a paracentric lock. It is distinguishable by

the contorted shape of its blade, which protrudes past the centre vertical line of the

key barrel. Instead of the wards on the outer face of the lock simply protruding into

the shape of the key along the spine, the wards protrude into the shape of the key

along the entire width of the key, including along the length of the teeth.[4] Patented

by the Yale lock company in 1898, paracentric cylinders are not exceptionally

difficult to pick, but this requires some skill and know-how.

Internal cut key

An internal cut (also known as "Sidewinder" or "Laser Cut") key has a rectangular

blade with a wavy groove cut up the center of the face of blade, at constant depth.

Typically the key has an identical wavy groove on the back of the blade, making it

symmetrical so it works no matter which way it is inserted. Also referred to as the

inner profile or sidewinder. These keys must be cut by special key cutting

machines made for them. [5]

Abloy key

Main article: disc tumbler lock

Abloy keys are cut from a metal half-cylinder. The cuts are made at different

angles, so when the key is turned in the lock it rotates each disk a different amount.

Nearly all the houses in Finland use Abloy keys, although they are also widely

used in various locales worldwide. These locks are considered very secure and

almost impossible to pick.[6][7][8]

Dimple key

A dimple key has a rectangular blade with various cone-shaped dimples drilled

into the face of the blade at various depths. Typically the lock has 2 rows of pins

that match up with 2 rows of dimples. Typically the key has the same dimple

pattern on the back of the blade, making it symmetrical so it works no matter

which way it is inserted.[9][10]

Kaba and Dom are manufactures of dimpled keys. These keys are considered very

secure and almost impossible to pick.[citation needed]

Skeleton key

A warded lock fits both its key and skeleton keys its size or smaller.

A skeleton key (or passkey) is a very simple design of key that usually has a

cylindrical shaft (sometimes called a shank) and a single, minimal flat, rectangular

tooth or bit. Skeleton keys are also usually distinguished by their bow, or the part

one would grasp when inserting the key, which can be either very plain or

extremely ornate. A skeleton key is designed to circumvent the wards in warded

locks. Warded locks and their keys provide minimal security and only a slight

deterrent as any key with a shaft and tooth that has the same or smaller dimensions

will open the lock. However, warded keys were designed to only fit a matching

lock and the skeleton key would often fit many. Many other objects that can fit into

the lock may also be able to open it.

Due to its limited usefulness, this type of lock fell out of use after more

complicated types became easier to manufacture. In modern usage, the term

"skeleton key" is often misapplied to ordinary bit keys and barrel keys, rather than

the correct definition: a key, usually with minimal features, which can open all or

most of a type of badly designed lock. Bit keys and barrel keys can be newly-

minted (and sold by restoration hardware companies) or antique stores.

They were most popular in the late 1800s, although they continued to be used well

into the 20th century and can still be found today in use, albeit in vintage homes

and antique furniture.

A bit key is distinguished from a barrel key in that a bit key usually has a solid

shank, whereas a barrel shafted key can be made either by drilling out the shank

from the bit end or by folding metal into a barrel shape when forging the key.

Tubular key

A tubular key

A tubular key (sometimes referred to as a barrel key when describing a vintage or

antique model) is one that is designed to open a tubular pin tumbler lock. It has a

hollow, cylindrical shaft that is usually much shorter and has a larger diameter than

most conventional keys. Antique or vintage-style barrel keys often closely

resemble the more traditional skeleton key but are a more recent innovation in

keymaking. In modern keys of this type, a number of grooves of varying length are

built into the outer surface at the end of the shaft. These grooves are parallel to the

shaft and allow the pins in the lock to slide to the end of the groove. A small tab on

the outer surface of the shaft prevents the pins in the lock from pushing the key out

and works with the hollow center to guide the key as it is turned.

The modern version of this type of key is harder to duplicate as it is less common

and requires a different machine from regular keys. These keys are most often seen

in home alarm systems, vending machines, and bicycle locks, in the United States.

These keys typically come in seven and eight-pin versions as well as miniature

versions which are used on computers. Tubular keys were invented by the Ace

lock company in Chicago.[citation needed]

Zeiss key

A Zeiss key (also known as a Cruciform key) is a cross between a house key and a

tubular key. It has three sets of teeth at 90 degrees to each other with a flattened

fourth side. Though this type of key is easy to duplicate, the extra sets of teeth

deter lockpicking attempts.

Do Not Duplicate key

A keychain, a simple way to hold keys

A Do Not Duplicate key (or DND key, for short) is one that has been stamped "do

not duplicate" and/or "duplication prohibited" or similar by a locksmith or

manufacturer as a passive deterrent to discourage a retail key cutting service from

duplicating a key without authorization or without contacting the locksmith or

manufacturer who originally cut the key. More importantly, this is a key control

system for the owner of the key, such as a maintenance person or security guard, to

identify keys that should not be freely distributed or used without authorization.

Though it is intended to prevent unauthorized key duplication, copying DND keys

remains a common security problem. There is no direct legal implication in the US

for someone who copies a key that is stamped do not duplicate (unless it is an

owned key), but there are patent restrictions on some key designs (see "restricted

keys"). The Associated Locksmiths of America, ALOA, calls DND keys "not

effective security", and "deceptive because it provides a false sense of security."

United States Code 18 USC Sec. 1704 deals with United States Post Office keys,

and 18 USC Sec. 1386 deals with United States Department of Defense keys.

Restricted key A restricted keyblank is a keyway and blank for which a

manufacturer has set up a restricted level of sales and distribution. Restricted keys

are often protected by patent, which prohibits other manufacturers from making

unauthorized productions of the key blank. In many cases, customers must provide

proof of ID before a locksmith will cut additional keys using restricted blanks.

These days, many restricted keys have special in-laid features, such as magnets,

different types of metal, or even small computer chips to prevent duplication.

Magnetic key

A magnetic keyed lock is a locking mechanism whereby the key utilizes magnets as

part of the locking and unlocking mechanism.

A magnetic key would use from one to many small magnets oriented so that the

North / South Poles would equate to a combination to push or pull the lock's

internal tumblers thus releasing the lock. This is a totally passive system requiring

no electricity or electronics to activate or deactivate the mechanism. Using several

magnets at differing polarity / orientations and different strengths can allow

thousands of different combinations per key.[11]

Keycard

A keycard is a flat, rectangular plastic card with identical dimensions to that of a

credit card or driver's license which stores a physical or digital signature which the

door mechanism accepts before disengaging the lock.

There are several popular type of keycards in use including the mechanical

holecard, bar code, magnetic stripe, Wiegand wire embedded cards, smart card

(embedded with a read/write electronic microchip), and RFID proximity

cards.Keycards are frequently used in hotels as an alternative to mechanical keys

7.2.7 RS232:

In telecommunications, RS-232 is a standard for serial binary data

interconnection between a DTE (Data terminal equipment) and a DCE (Data

Circuit-terminating Equipment). It is commonly used in computer serial ports.

Scope of the Standard:

The Electronic Industries Alliance (EIA) standard RS-232-C [3] as of 1969

defines:

Electrical signal characteristics such as voltage levels, signaling rate, timing

and slew-rate of signals, voltage withstand level, short-circuit behavior,

maximum stray capacitance and cable length

Interface mechanical characteristics, pluggable connectors and pin

identification

Functions of each circuit in the interface connector

Standard subsets of interface circuits for selected telecom applications

The standard does not define such elements as character encoding (for example,

ASCII, Baudot or EBCDIC), or the framing of characters in the data stream (bits

per character, start/stop bits, parity). The standard does not define protocols for

error detection or algorithms for data compression.

The standard does not define bit rates for transmission, although the standard

says it is intended for bit rates lower than 20,000 bits per second. Many modern

devices can exceed this speed (38,400 and 57,600 bit/s being common, and

115,200 and 230,400 bit/s making occasional appearances) while still using RS-

232 compatible signal levels.

Details of character format and transmission bit rate are controlled by the serial

port hardware, often a single integrated circuit called a UART that converts data

from parallel to serial form. A typical serial port includes specialized driver and

receiver integrated circuits to convert between internal logic levels and RS-232

compatible signal levels.

7.2.8 GSM MODEM

A GSM modem is a specialized type of modem which accepts a SIM card, and

operates over a subscription to a mobile operator, just like a mobile phone. From

the mobile operator perspective, a GSM modem looks just like a mobile phone.

For the purpose of this document, the term GSM modem is used as a generic term

to refer to any modem that supports one or more of the protocols in the GSM

evolutionary family, including the 2.5G technologies GPRS and EDGE, as well as

the 3G technologies WCDMA, UMTS, HSDPA and HSUPA.

A GSM modem exposes an interface that allows applications such as NowSMS to

send and receive messages over the modem interface. The mobile operator charges

for this message sending and receiving as if it was performed directly on a mobile

phone. To perform these tasks, a GSM modem must support an “extended AT

command set” for sending/receiving SMS messages, as defined in the ETSI GSM

07.05 and and 3GPP TS 27.005 specifications.

GSM modems can be a quick and efficient way to get started with SMS, because a

special subscription to an SMS service provider is not required. In most parts of the

world, GSM modems are a cost effective solution for receiving SMS messages,

because the sender is paying for the message delivery.

A GSM modem can be a dedicated modem device with a serial, USB or Bluetooth

connection, such as the Falcom Samba 75 used in this document. (Other

manufacturers of dedicated GSM modem devices include Wavecom, Multitech and

iTegno.) To begin, insert a GSM SIM card into the modem and connect it to an

available USB port on your computer.

A GSM modem could also be a standard GSM mobile phone with the appropriate

cable and software driver to connect to a serial port or USB port on your computer.

Any phone that supports the “extended AT command set” for sending/receiving

SMS messages, as defined in ETSI GSM 07.05 and/or 3GPP TS 27.005, can be

supported by the Now SMS & MMS Gateway. Note that not all mobile phones

support this modem interface.

Due to some compatibility issues that can exist with mobile phones, using a

dedicated GSM modem is usually preferable to a GSM mobile phone. This is more

of an issue with MMS messaging, where if you wish to be able to receive inbound

MMS messages with the gateway, the modem interface on most GSM phones will

only allow you to send MMS messages. This is because the mobile phone

automatically processes received MMS message notifications without forwarding

them via the modem interface.

It should also be noted that not all phones support the modem interface for sending

and receiving SMS messages. In particular, most smart phones, including

Blackberries, iPhone, and Windows Mobile devices, do not support this GSM

modem interface for sending and receiving SMS messages at all at all.

Additionally, Nokia phones that use the S60 (Series 60) interface, which is

Symbian based, only support sending SMS messages via the modem interface, and

do not support receiving SMS via the modem interface.

When you install your GSM modem, or connect your GSM mobile phone to the

computer, be sure to install the appropriate Windows modem driver from the

device manufacturer. To simplify configuration, the Now SMS & MMS Gateway

will communicate with the device via this driver. If a Windows driver is not

available for your modem, you can use either the “Standard” or “Generic” 33600

bps modem driver that is built into windows. A benefit of utilizing a Windows

modem driver is that you can use Windows diagnostics to ensure that the modem is

communicating properly with the computer.

The Now SMS & MMS gateway can simultaneously support multiple modems,

provided that your computer hardware has the available communications port

resources.

7.2.9 KEYPAD:

A numeric keypad, or numpad for short, is the small, palm-sized, seventeen key

section of a computer keyboard, usually on the very far right. The numeric keypad

features digits 0 to 9, addition (+), subtraction (-), multiplication (*) and division

(/) symbols, a decimal point (.) and Num Lock and Enter keys. Laptop keyboards

often do not have a numpad, but may provide numpad input by holding a modifier

key (typically lapelled "Fn") and operating keys on the standard keyboard.

Particularly large laptops (typically those with a 17 inch screen or larger)

may have space for a real numpad, and many companies sell separate numpads

which connect to the host laptop by a USB connection.

Numeric keypads usually operate in two modes: when Num Lock is off,

keys 8, 6, 2, 4 act like an arrow keys and 7, 9, 3, 1 act like Home, PgUp, PgDn and

End; when Num Lock is on, digits keys produce corresponding digits. These,

however, differ from the numeric keys at the top of the keyboard in that, when

combined with the Alt key on a PC, they are used to enter characters which may

not be otherwise available: for example, Alt-0169 produces the copyright symbol.

These are referred to as Alt codes.

On Apple Computer Macintosh computers, which lack a Num Lock key, the

numeric keypad always produces only numbers. The num lock key is replaced by

the clear key.

Numeric keypads usually operate in two modes: when Num Lock is off,

keys 8, 6, 2, 4 act like an arrow keys and 7, 9, 3, 1 act like Home, PgUp, PgDn and

End; when Num Lock is on, digits keys produce corresponding digits. These,

however, differ from the numeric keys at the top of the keyboard in that, when

combined with the Alt key on a PC, they are used to enter characters which may

not be otherwise available: for example, Alt-0169 produces the copyright symbol.

These are referred to as Alt codes.

7.2.10 RF TRANSMITTER RECEIVER

Radio frequency (RF) radiation is a subset of electromagnetic radiation with a

wavelength of 100km to 1mm, which is a frequency of 3 KHz to 300 GHz,[1]

respectively. This range of electromagnetic radiation constitutes the radio

spectrum and corresponds to the frequency of alternating current electrical signals

used to produce and detect radio waves. RF can refer to electromagnetic

oscillations in either electrical circuits or radiation through air and space. Like

other subsets of electromagnetic radiation, RF travels at the speed of light.

1.3 Radio communication

In order to receive radio signals, for instance from AM/FM radio stations, a radio

antenna must be used. However, since the antenna will pick up thousands of radio

signals at a time, a radio tuner is necessary to tune in to a particular frequency (or

frequency range).[2] This is typically done via a resonator (in its simplest form, a

circuit with a capacitor and an inductor). The resonator is configured to resonate at

a particular frequency (or frequency band), thus amplifying sine waves at that radio

frequency, while ignoring other sine waves. Usually, either the inductor or the

capacitor of the resonator is adjustable, allowing the user to change the frequency

at which it resonates.[3]

1.4

1.5 Special properties of RF electrical signals

Electrical currents that oscillate at RF have special properties not shared by direct

current signals. One such property is the ease with which they can ionize air to

create a conductive path through air. This property is exploited by 'high frequency'

units used in electric arc welding, although strictly speaking these machines do not

typically employ frequencies within the HF band. Another special property is an

electromagnetic force that drives the RF current to the surface of conductors,

known as the skin effect. Another property is the ability to appear to flow through

paths that contain insulating material, like the dielectric insulator of a capacitor.

The degree of effect of these properties depends on the frequency of the signals.

Radio spectrum

Radio spectrum refers to the part of the electromagnetic spectrum corresponding

to radio frequencies – that is, frequencies lower than around 300 GHz (or,

equivalently, wavelengths longer than about 1 mm).

Different parts of the radio spectrum are used for different radio transmission

technologies and applications. Radio spectrum is typically government regulated in

developed countries, and in some cases is sold or licensed to operators of private

radio transmission systems (for example, cellular telephone operators or broadcast

television stations). Ranges of allocated frequencies are often referred to by their

provisioned use (for example, cellular spectrum or television spectrum)

1.6

1.7 Bands

Band

nameAbbr

ITU

band

Frequency

and

wavelength in air

Example uses

subHertz subHz 0< 3 Hz

> 100,000 km

Natural and man-made

electromagnetic waves

(millihertz, microhertz,

nanohertz) from earth,

ionosphere, sun, planets, etc[citation

needed]

Extremely

low

frequency

ELF 13–30 Hz

100,000 km – 10,000 kmCommunication with submarines

Super low

frequencySLF 2

30–300 Hz

10,000 km – 1000 kmCommunication with submarines

Ultra low

frequencyULF 3

300–3000 Hz

1000 km – 100 kmCommunication within mines

Very low

frequencyVLF 4

3–30 kHz

100 km – 10 km

Submarine communication,

avalanche beacons, wireless heart

rate monitors, geophysics

Low

frequencyLF 5

30–300 kHz

10 km – 1 km

Navigation, time signals, AM

longwave broadcasting, RFID

Medium

frequencyMF 6

300–3000 kHz

1 km – 100 mAM (medium-wave) broadcasts

High

frequencyHF 7

3–30 MHz

100 m – 10 m

Shortwave broadcasts, amateur

radio and over-the-horizon

aviation communications, RFID

Very high

frequencyVHF 8

30–300 MHz

10 m – 1 m

FM, television broadcasts and

line-of-sight ground-to-aircraft

and aircraft-to-aircraft

communications. Land Mobile

and Maritime Mobile

communications

Ultra high

frequencyUHF 9

300–3000 MHz

1 m – 100 mm

Television broadcasts,

microwave ovens, mobile

phones, wireless LAN,

Bluetooth, GPS and two-way

radios such as Land Mobile, FRS

and GMRS radios

Super high

frequencySHF 10

3–30 GHz

100 mm – 10 mm

Microwave devices, wireless

LAN, most modern radars

Extremely

high

frequency

EHF 1130–300 GHz

10 mm – 1 mm

Radio astronomy, high-frequency

microwave radio relay

Terahertz THz 12300–3,000 GHz

1 mm – 100 μm

Terahertz imaging – a potential

replacement for X-rays in some

medical applications, ultrafast

molecular dynamics, condensed-

matter physics, terahertz time-

domain spectroscopy, terahertz

computing/communications

1.7.1 Notes

Above 300 GHz, the absorption of electromagnetic radiation by Earth's

atmosphere is so great that the atmosphere is effectively opaque, until it

becomes transparent again in the infrared and optical window frequency

ranges.

The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency)

spectrum, which is approximately 20–20,000 Hz. However, sounds are

transmitted by atmospheric compression and expansion, and not by

electromagnetic energy.

The SHF and EHF bands are sometimes not considered to be a part of the radio

spectrum, forming their own microwave spectrum.

7.2.11 ENCODER AND DECODER

An encoder is a device, circuit, transducer, software program, algorithm or person

that converts information from one format or code to another, for the purposes of

standardization, speed, secrecy, security, or saving space by shrinking size.

A decoder is a device which does the reverse of an encoder, undoing the encoding

so that the original information can be retrieved. The same method used to encode

is usually just reversed in order to decode.

In digital electronics, a decoder can take the form of a multiple-input, multiple-

output logic circuit that converts coded inputs into coded outputs, where the input

and output codes are different. e.g. n-to-2n, binary-coded decimal decoders. Enable

inputs must be on for the decoder to function, otherwise its outputs assume a single

"disabled" output code word. Decoding is necessary in applications such as data

multiplexing, 7 segment display and memory address decoding.

The example decoder circuit would be an AND gate because the output of an AND

gate is "High" (1) only when all its inputs are "High." Such output is called as

"active High output". If instead of AND gate, the NAND gate is connected the

output will be "Low" (0) only when all its inputs are "High". Such output is called

as "active low output".

A slightly more complex decoder would be the n-to-2n type binary decoders. These

type of decoders are combinational circuits that convert binary information from 'n'

coded inputs to a maximum of 2n unique outputs. We say a maximum of 2n outputs

because in case the 'n' bit coded information has unused bit combinations, the

decoder may have less than 2n outputs. We can have 2-to-4 decoder, 3-to-8 decoder

or 4-to-16 decoder. We can form a 3-to-8 decoder from two 2-to-4 decoders (with

enable signals).

Similarly, we can also form a 4-to-16 decoder by combining two 3-to-8 decoders.

In this type of circuit design, the enable inputs of both 3-to-8 decoders originate

from a 4th input, which acts as a selector between the two 3-to-8 decoders. This

allows the 4th input to enable either the top or bottom decoder, which produces

outputs of D(0) through D(7) for the first decoder, and D(8) through D(15) for the

second decoder.

A decoder that contains enable inputs is also known as a decoder-demultiplexer.

Thus, we have a 4-to-16 decoder produced by adding a 4th input shared among

both decoders, producing 16 outputs.

7.2.12 TRAFFIC LIGHTS:

Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, stop-and-go lights[robotsor semaphore] are signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic. Traffic lights have been installed in most cities around the world. They assign the right of way to road users by the use of lights in standard colors (Red - Yellow - Green), using a universal color code (and a precise sequence, for those who are color blind).

Typically traffic lights consist of a set of three colored lights: red, yellow and green. In a typical cycle,

Illumination of the green light allows traffic to proceed in the direction denoted,

Illumination of the yellow light denoting if safe to, prepare to stop short of the intersection, and

Illumination of the red signal prohibits any traffic from proceeding.

Usually, the red light contains some orange in its hue, and the green light contains some blue, to provide some support for people with red-green color blindness.

History

On December 10, 1868, the first traffic lights were installed outside the British Houses of Parliament in London, by the railway engineer J. P. Knight. They resembled railway signals of the time, with semaphore arms and red and green gas lamps for night use. The gas lantern was turned with a lever at its base so that the appropriate light faced traffic. Unfortunately, it exploded on 2 January 1869, injuring[3] or killing[4] the policeman who was operating it.

The modern electric traffic light is an American invention.[5] As early as 1912 in Salt Lake City, Utah, policeman Lester Wire invented the first red-green electric traffic lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio.[6][7] It had two colors, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for color changes. The design by James Hoge[8] allowed police and fire stations to control the signals in case of emergency. The first four-way, three-color traffic light was created by police officer William Potts in Detroit, Michigan in 1920.[9] In 1922, T.E. Hayes patented his "Combination traffic guide and traffic regulating signal" (Patent # 1447659). Ashville, Ohio claims to be the location of the oldest working traffic light in the United States, used at an intersection of public roads until 1982 when it was moved to a local museum.[10]

The first interconnected traffic signal system was installed in Salt Lake City in 1917,[citation needed] with six connected intersections controlled simultaneously from a manual switch. Automatic control of interconnected traffic lights was introduced March 1922 in Houston, Texas.[11] The first automatic experimental traffic lights in England were deployed in Wolverhampton in 1927.[12]

The color of the traffic lights representing stop and go might be derived from those used to identify port (red) and starboard (green) in maritime rules governing right of way, where the vessel on the left must stop for the one crossing on the right.

Timers on traffic lights originated in Taipei, Taiwan, and brought to the US after an engineer discovered its use. Though uncommon in most American urban areas, timers are still used in some other Western Hemisphere countries. Timers are useful for drivers/pedestrians to plan if there is enough time to attempt to cross the intersection before the light turns red and conversely, the amount of time before the light turns green.

7.3 OVERALL CIRCUIT DIAGRAM:

7.4. OVERALL CIRCUIT DIAGRAM DESCRIPTION:

7.4.1 POWER SUPPLY:

Block diagram

The ac voltage, typically 220V rms, is connected to a transformer, which

steps that ac voltage down to the level of the desired dc output. A diode rectifier

then provides a full-wave rectified voltage that is initially filtered by a simple

capacitor filter to produce a dc voltage. This resulting dc voltage usually has some

ripple or ac voltage variation.

A regulator circuit removes the ripples and also remains the same dc value

even if the input dc voltage varies, or the load connected to the output dc voltage

changes. This voltage regulation is usually obtained using one of the popular

voltage regulator IC units.

1.7.1.1.1.1

Block diagram (Power supply)

Working principle

TRANSFORMER RECTIFIER

FILTERIC REGULATOR

LOAD

Transformer

The potential transformer will step down the power supply voltage (0-

230V) to (0-6V) level. Then the secondary of the potential transformer will be

connected to the precision rectifier, which is constructed with the help of op–

amp. The advantages of using precision rectifier are it will give peak voltage

output as DC, rest of the circuits will give only RMS output.

Bridge rectifier

When four diodes are connected as shown in figure, the circuit is called as

bridge rectifier. The input to the circuit is applied to the diagonally opposite

corners of the network, and the output is taken from the remaining two corners.

Let us assume that the transformer is working properly and there is a

positive potential, at point A and a negative potential at point B. the positive

potential at point A will forward bias D3 and reverse bias D4.

The negative potential at point B will forward bias D1 and reverse D2. At

this time D3 and D1 are forward biased and will allow current flow to pass

through them; D4 and D2 are reverse biased and will block current flow.

The path for current flow is from point B through D1, up through RL,

through D3, through the secondary of the transformer back to point B. this path is

indicated by the solid arrows. Waveforms (1) and (2) can be observed across D1

and D3.

One-half cycle later the polarity across the secondary of the transformer

reverse, forward biasing D2 and D4 and reverse biasing D1 and D3. Current flow

will now be from point A through D4, up through RL, through D2, through the

secondary of T1, and back to point A. This path is indicated by the broken arrows.

Waveforms (3) and (4) can be observed across D2 and D4. The current flow

through RL is always in the same direction. In flowing through RL this current

develops a voltage corresponding to that shown waveform (5). Since current

flows through the load (RL) during both half cycles of the applied voltage, this

bridge rectifier is a full-wave rectifier.

One advantage of a bridge rectifier over a conventional full-wave rectifier is

that with a given transformer the bridge rectifier produces a voltage output that is

nearly twice that of the conventional full-wave circuit.

This may be shown by assigning values to some of the components shown in

views A and B. assume that the same transformer is used in both circuits. The peak

voltage developed between points X and y is 1000 volts in both circuits. In the

conventional full-wave circuit shown—in view A, the peak voltage from the center

tap to either X or Y is 500 volts. Since only one diode can conduct at any instant,

the maximum voltage that can be rectified at any instant is 500 volts.

The maximum voltage that appears across the load resistor is nearly-but

never exceeds-500 v0lts, as result of the small voltage drop across the diode. In the

bridge rectifier shown in view B, the maximum voltage that can be rectified is the

full secondary voltage, which is 1000 volts. Therefore, the peak output voltage

across the load resistor is nearly 1000 volts. With both circuits using the same

transformer, the bridge rectifier circuit produces a higher output voltage than the

conventional full-wave rectifier circuit.

IC voltage regulators

Voltage regulators comprise a class of widely used ICs. Regulator IC

units contain the circuitry for reference source, comparator amplifier, control

device, and overload protection all in a single IC. IC units provide regulation of

either a fixed positive voltage, a fixed negative voltage, or an adjustably set

voltage. The regulators can be selected for operation with load currents from

hundreds of milli amperes to tens of amperes, corresponding to power ratings

from milli watts to tens of watts.

Circuit diagram (Power supply)

A fixed three-terminal voltage regulator has an unregulated dc input

voltage, Vi, applied to one input terminal, a regulated dc output voltage, Vo, from

a second terminal, with the third terminal connected to ground.

The series 78 regulators provide fixed positive regulated voltages from 5 to

24 volts. Similarly, the series 79 regulators provide fixed negative regulated

voltages from 5 to 24 volts.

For ICs, microcontroller, LCD --------- 5 volts

For alarm circuit, op-amp, relay circuits ---------- 12 volts

7.4.2 LCD WITH PIC MICRO CONTROLLER:

We connect the lcd display with PIC through PORT D.

PORTD AND TRISD REGISTER :

PORTD is an 8-bit wide bi-directional port.

The corresponding data direction register is TRISD. Setting a TRISD bit (=1) will

make the corresponding PORTD pin an input, i.e., put the corresponding output

driver in a hi-impedance mode. Clearing a TRISD bit (=0) will make the

corresponding PORTD pin an output.

PORTD AND TRISD REGISTERS:

This section is not applicable to the 28-pin

devices. PORTD is an 8-bit port with Schmitt Trigger input buffers. Each pin is

individually configurable as an input or output. PORTD can be configured as an 8-

bit wide microprocessor Port (parallel slave port) by setting control bit PSPMODE

(TRISE<4>). In this mode, the input buffers are TTL.

PORTD FUNCTIONS

SUMMARY OF REGISTERS ASSOCIATED WITH PORTD

a) Any read or write of PORTD. This will end the mismatch condition.

b) Clear flag bit RBIF. A mismatch condition will continue to

set flag bit RBIF. Reading PORTD will end the mismatch condition, and

allow flag bit RBIF to be cleared. The interrupt on change feature is

recommended for wake-up on key depression operation and operations

where PORTD is only used for the interrupt on change feature. Polling of

PORTD is not recommended while using the interrupt on change feature.

This interrupt on mismatch feature, together with software configurable pull-

ups on these four pins, allow easy interface to a keypad and make it possible

for wake-up on key depression

7.4.3 VIBRATION

Piezo Electric Sensor:

A piezoelectric sensor is a device that uses the piezoelectric effect to

measure pressure, acceleration, strain or force by converting them to an electrical

signal.

Piezo Electric Effect:

Piezoelectricity is the ability of crystals and certain ceramic materials to

generate a voltage in response to applied mechanical stress. Piezoelectricity was

discovered by Pierre Curie and the word is derived from the Greek piezein, which

means to squeeze or press.

The piezoelectric effect is reversible in that piezoelectric crystals, when

subjected to an externally applied voltage, can change shape by a small amount.

(For instance, the deformation is about 0.1% of the original dimension in PZT.)

The effect finds useful applications such as the production and detection of sound,

generation of high voltages, electronic frequency generation, microbalance, and

ultra fine focusing of optical assemblies.

Application:

Piezoelectric sensors have proven to be versatile tools for the measurement

of various processes. They are used for quality assurance, process control and

process development in many different industries.

Piezo electric sensors are also seen in nature. Bones act as force sensors.

Once loaded, bones produce charges proportional to the resulting internal torsion

or displacement. Those charges stimulate and drive the build up of new bone

material. This leads to the strengthening of structures where the internal

displacements are the greatest. With time, this causes weaker structures to increase

their strength and stability as material is laid down proportional to the forces

affecting the bone.

Circuit Description:

Vibration circuit is used to sense the mechanical vibration. This circuit is

constructed with

1. Piezo electric plate.

2. Operational amplifier

3. 555 IC timer

Piezo electric plate is the special type of sensor which is used to sense the

mechanical vibration. Piezo electric plate converts the mechanical vibration to

electrical signal. The converted electrical signal is in the range of small milli

voltage signal.

Then the electrical signal voltage is given to amplifier unit through 0.1uf

capacitor in order to filter the noise signal. The amplifier circuit is constructed with

operational amplifier LM 741. The amplified output is in the form of AC signal the

diode is used to rectify the negative signal.

7.4.4 RS232:

In telecommunications, RS-232 is a standard for serial binary data

interconnection between a DTE (Data terminal equipment) and a DCE (Data

Circuit-terminating Equipment). It is commonly used in computer serial ports.

Scope of the Standard:

The Electronic Industries Alliance (EIA) standard RS-232-C [3] as of 1969

defines:

Electrical signal characteristics such as voltage levels, signaling rate, timing

and slew-rate of signals, voltage withstand level, short-circuit behavior,

maximum stray capacitance and cable length

Interface mechanical characteristics, pluggable connectors and pin

identification

Functions of each circuit in the interface connector

Standard subsets of interface circuits for selected telecom applications

The standard does not define such elements as character encoding (for example,

ASCII, Baudot or EBCDIC), or the framing of characters in the data stream (bits

per character, start/stop bits, parity). The standard does not define protocols for

error detection or algorithms for data compression.

The standard does not define bit rates for transmission, although the standard

says it is intended for bit rates lower than 20,000 bits per second. Many modern

devices can exceed this speed (38,400 and 57,600 bit/s being common, and

115,200 and 230,400 bit/s making occasional appearances) while still using RS-

232 compatible signal levels.

Details of character format and transmission bit rate are controlled by the serial

port hardware, often a single integrated circuit called a UART that converts data

from parallel to serial form. A typical serial port includes specialized driver and

receiver integrated circuits to convert between internal logic levels and RS-232

compatible signal levels.

Circuit working Description:

In this circuit the MAX 232 IC used as level logic converter. The MAX232

is a dual driver/receiver that includes a capacive voltage generator to supply EIA

232 voltage levels from a single 5v supply. Each receiver converts EIA-232 to 5v

TTL/CMOS levels. Each driver converts TLL/CMOS input levels into EIA-232

levels.

In this circuit the microcontroller transmitter pin is connected in the

MAX232 T2IN pin which converts input 5v TTL/CMOS level to RS232 level.

Then T2OUT pin is connected to reviver pin of 9 pin D type serial connector

which is directly connected to PC.

In PC the transmitting data is given to R2IN of MAX232 through

transmitting pin of 9 pin D type connector which converts the RS232 level to 5v

TTL/CMOS level. The R2OUT pin is connected to receiver pin of the

microcontroller. Likewise the data is transmitted and received between the

microcontroller and PC or other device vice versa.

7.4.5 ENCODER WITH RF TRANSMITTER:

Encoder:

In this circuit HT 640 is used as encoder. The 318 encoders are a series of

CMOS LSIs for remote control system application. They are capable of encoding

18 bits of information which consists of N address bit and 18-N data bits. Each

address/data input is externally trinary programmable if bonded out. It is otherwise

set floating internally. Various packages of the 318 encoders offer flexible

combination of programmable address/data is transmitted together with the header

bits via an RF or an infrared transmission medium upon receipt of a trigger signal.

The capability to select a TE trigger type further enhances the application

flexibility of the 318 series of encoders.

In this circuit the input signal to be encoded is given to AD7-AD0 input pins of

encoder. Here the input signal may be from key board, parallel port,

microcontroller or any interfacing device. The encoder output address pins are

shorted so the output encoded signal is the combination of (A0-A9) address signal

and (D0-D7) data signal. The output encoded signal is taken from 8th which is

connected to RF transmitter section.

RF Transmitter:

When ever the high output pulse is given to base of the transistor BF

494, the transistor is conducting so tank circuit is oscillated. The tank circuit is

consists of L2 and C4 generating 433 MHz carrier signal. Then the modulated

signal is given LC filter section. After the filtration the RF modulated signal is

transmitted through antenna.

7.4.6 DECODER WITH RF RECIVER:

RF Receiver:

The RF receiver is used to receive the encoded data which is

transmitted by the RF transmitter. Then the received data is given to transistor

which acts as amplifier. Then the amplified signal is given to carrier demodulator

section in which transistor Q1 is turn on and turn off conducting depends on the

signal. Due to this the capacitor C14 is charged and discharged so carrier signal is

removed and saw tooth signal is appears across the capacitor. Then this saw tooth

signal is given to comparator. The comparator circuit is constructed by LM558.

The comparator is used to convert the saw tooth signal to exact square pulse. Then

the encoded signal is given to decoder in order to get the decoded original signal.

Decoder:

In this circuit HT648 is used as decoder. The 318 decoder are a series of

CMOS LSIs for remote control system application. They are paired with 3 18 series

of encoders. For proper operation a pair of encoder/decoder pair with the same

number of address and data format should be selected. The 318 series of decoder

receives serial address and data from that series of encoders that are transmitted by

a carrier using an RF or an IR transmission medium. It then compares the serial

input data twice continuously with its local address. If no errors or unmatched

codes are encountered, the input data codes are decoded and then transferred to the

output pins. The VT pin also goes high to indicate a valid transmission.

The 318 decoders are capable of decoding 18 bits of information that consists of

N bits of address and 18-N bits of data. To meet various applications they are

arranged to provide a number of data pins whose range is from 0 t08 and an

address pin whose range is from 8 to 18. In addition, the 318 decoders provide

various combinations of address/ data numbering different package.

In this circuit the received encoded signal is 9th pin of the decoder. Now the

decoder separate the address (A0-A9) and data signal (D0-D7). Then the output

data signal is given to microcontroller or any other interfacing device.

7.4.7 RELAY:

Circuit description:

This circuit is designed to control the load. The load may be motor or any

other load. The load is turned ON and OFF through relay. The relay ON and OFF is

controlled by the pair of switching transistors (BC 547). The relay is connected in

the Q2 transistor collector terminal. A Relay is nothing but electromagnetic

switching device which consists of three pins. They are Common, Normally close

(NC) and Normally open (NO).

The relay common pin is connected to supply voltage. The normally open (NO)

pin connected to load. When high pulse signal is given to base of the Q1

transistors, the transistor is conducting and shorts the collector and emitter

terminal and zero signals is given to base of the Q2 transistor. So the relay is

turned OFF state.

When low pulse is given to base of transistor Q1 transistor, the

transistor is turned OFF. Now 12v is given to base of Q2 transistor so the

transistor is conducting and relay is turned ON. Hence the common terminal and

NO terminal of relay are shorted. Now load gets the supply voltage through relay.

Voltage Signal from Transistor Q1 Transistor Q2 Relay

Microcontroller or PC

1 on off off

0 off on on

8.ADVANTAGES

LOW COST

RELIABILITY

EASY TO IMPLEMENTATION

9.APPLICATIONS

CONCLUSION

The progress in science & technology is a non-stop process. New things and new technology

are being invented. As the technology grows day by day, we can imagine about the future in

which thing we may occupy every place.

The proposed system based on Atmel microcontroller is found to be more

compact, user friendly and less complex, which can readily be used in order to

perform. Several tedious and repetitive tasks. Though it is designed keeping in

mind about the need for industry, it can extended for other purposes such as

commercial & research applications. Due to the probability of high technology

(Atmel microcontroller) used this” AUTOMATIC AMBULANCE RESCUE

SYSTEM CORDIALITY SERVICES” is fully software controlled with less

hardware circuit. The feature makes this system is the base for future systems.

The principle of the development of science is that “nothing is impossible”. So we

shall look forward to a bright & sophisticated world.

REFERENCE

MILL MAN J and HAWKIES C.C. “INTEGRATED

ELECTRONICS” MCGRAW HILL, 1972

ROY CHOUDHURY D, SHAIL JAIN, “ LINEAR INTEGRATED

CIRCUIT”, New Age International Publishers, New Delhi,2000

“THE 8051 MICROCONTROLLER AND EMBEDDED SYSTEM”

by Mohammad Ali Mazidi.

WEBSITES:

http://www.atmel.com/

http://www.microchip.com/

www.8052.com

http://www.beyondlogic.org

http://www.ctv.es/pckits/home.html

http://www.aimglobal.org/