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PROJECT REPORT Submitted by S. SRIARAVINDHAN

263370214

A. MADHUSUDHAN

263570275

I. PRASANNARAM

263570303

K. VEERAMANI

263570372

Under the guidance of Mr.S.SIVAKUMAR M.E

Lecturer,Department of EEE In partial fulfillment of the requirement for the degree of BACHELOR OF TECHNOLOGY In ELECTRICAL AND ELECTRONICS ENGINEERING OF PUDUCHERRY UNIVERSITY

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING RAJIV GANDHI COLLEGE OF ENGINEERING AND TECH NOLOGY KIRUMAMPAKKAM,PUDUCHERRY-607402 JUNE 2009

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IMPLEMENTATION OF GSM FOR MODERN RAILWAYS AND ACCIDENT PREVENTION AT RAILWAY DEDICATED LINES

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DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY PUDUCHERRY – 607402 BONAFIDE CERTIFICATE This is to certify that this dissertation titled “Implementation of gsm for modern railways and accident prevention at railway dedicated lines“ is a bonafide work done by S. SRIARAVINDHAN

263370214

A. MADHUSUDHAN

263570275

I. PRASANNARAM

263570303

K. VEERAMANI

263570372

In partial fulfillment for the award of the degree of Bachelor of technology in Electrical and Electronics Engineering in Rajiv Gandhi College of Engineering and Technology, affiliated to Puducherry University during the year 2009 and that this work has not been submitted for the award of any other degree.

GUIDE (Mr.S. SIVAKUMAR)

HEAD OF DEPARTMENT (Mr.M. MANOHARAN)

Submitted for the University Examination held on ………………...

INTERNAL EXAMINER

EXTERNAL EXAMINER

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ACKNOWLEDGEMENT

We thank the invisible superior power for giving us the perseverance to do this project We express our heartfelt thanks to Mr. M.K. Rajagopalan, chairman, Rajiv Gandhi College Engineering and Technology, Puducherry for his support for the completion of our project.

Gratitute is also extended to Mr.V.Bhaskaran, Administrator, for his constant encouragement and co-operation throught the project.

Our heartfelt thanks to Dr.A.Venkataraman, principal, for giving us support to complete our esteemed project.

We also thank Mr. M.Manoharan, H.O.D of Electrical and Electronics department for his assistance and encouragement throught the project.

We owe our achievement to the inspiration and kind guidance to Mr. S.Sivakumar,Lecturer, Department of Electrical and Electronics Engineering and we are thankful for his sincere guidance as our internal guide to successfully complete our project.

We acknowledge our reverential gratitude to all the faculty members and lab staffs in department of Electrical and Electronics Engineering, for their vital and timely help.

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We express our deep sense of gratitude to our family members and to our dear friends for their support and encouragement during the entire course of study.

S. SRIARAVINDHAN A. MADHUSUDHAN I. PRASANNARAM K. VEERAMANI

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SL.NO

TERMS

EXPLANATION

1

GSM-R

Global System for Mobile Communication – Railways

2

IR

Infra Red Sensor

3

SMS

Short Message Sending

4

HR

Half Rate

5

FR

Full Rate

6

EFR

Enhanced Full Rate

7

AMR

Adaptive Multirate

8

TTL

Transistor Transistor Logic

9

LED

Light Emitting Diode

10

DTE

Data Terminal Equipment

11

DCE

Date Communication Equipment

12

CMOS

Complementary Metal Oxide Semiconductor

13

EPROM

Erasable Programmable Read Only Memory

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ABBREVIATIONS

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ABSTRACT The proposed Implementation of GSM for modern railways and accident prevention at railway dedicated lines is a special class of distributed data network. The demand for high quality railway service in the twenty first century has put an ever increasing demand on all railway operators to meet the expectation of all peoples. In order to meet the expectation of the peoples, a highly safety system have been developed to prevent railway accidents at crossings as well as at passenger railway dedicated lines and an highly efficient communication system has been developed, so that a passenger as well as railway system has an effective communication system without any complicated systems. This system is capable of preventing accidents and sending messages to the passengers. It consists of GSM-R, Ultrasonic sensors, and IR sensors, microcontrollers and control centres. The application of this system is to provide streamline communication with online monitoring of accident prevention and real time railway network for communication.

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INTRODUCTION

1.1 INTRODUCTION OF THE PROJECT

Now a days, India is the country which having worlds largest railway network. Over hundreds of railways running on track everyday. As railway has straightway running as well as it has somewhat risky and dangerous as per as general public and traffic concern. In recent years, Indian railway network is facing serious problem of inefficient communication to the passengers and poor accident prevention at railway dedicated lines due to lack of well planned projects in railway network. The information about the arrival and departure time of railways on the displays is always showing incorrect timings. All the steps taken so far, regarding the improvement of the railway timings did not yield satisfactory results. It is reported that the most efficient way of providing railway timings is the effective communication system, which have been improved by well planned projects.

Communication systems are truly the best way to provide correct timings regarding arrival and departure of railways on a real time basis. Furthermore, if automatic gate locking and obstacle detection is done in a dynamic fashion, efficiency can be maintained long term, something that is not often achieved today.

Communication systems involves GSM-R, IR sensors and Ultrasonic sensors will become a big issue in this process. In this system, GSM-R is to provide accurate timings regarding arrival and departure of railways to the passengers and peoples at the railway station. IR sensors is to detect railway movement across the crossing and lines to provide information about timings to the control circuit. Ultrasonic sensors is to detect obstacles across the lines during train movement and report to the driver to take immediate action.

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CHAPTER 1

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The goal of this project is to design an embedded hardware using microcontroller – a controlling device, which performs effective communication to the passengers and peoples at the railway station regarding arrival and departure timings of railways with the help of GSR-R modem and IR sensors, preventing accidents across the crossings and lines by means of automatic gate locking system and

obstacle

detection with the help of shunt motor, Ultrasonic sensors.

1.2 SCOPE OF THE PROPOSED WORK ·

High efficient data transfer regarding arrival and departure time of Trains can be achieved by means of GSM-R technology.

·

Saving of passenger’s time can be achieved by means of frequent data transmission through SMS.

·

Detection of moving train can be done with the help of IR sensors.

·

Automatic gate locking can be done with the help of IR sensors, microcontroller and shunt motor.

·

Prevention of accidents in unmanned railway crossings can be achieved .

·

Accurate detection of obstacles in railway tracks can be done with the help of Ultrasonic sensors.

·

If manned

railway gate crossings are replaced by automatic railway gate

control,then it greatly reduces the huge expense spent for manned operation thereby greatly increases overall efficiency of the whole railway system.

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The report is organized as follows

1.4 CONCLUSION This chapter gives the brief introduction of the entire project.The organization of the project report is also discussed in this chapter.

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1.3 ORGANIZATION OF THE PROJECT

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PROBLEM DESCRIPTION 2.1 INTRODUCTION This chapter deals with the various problem faced in the present day railway system and the ways to recover from these problems.

2.2 PROBLEM DESCRIPTION At present scenario, in level crossings, the railway gate is operated normally by a gate keeper after receiving the information about the train's arrival. When a train starts to leave a station, station master of the particular station delivers the information to the near by gate. The above said procedures are followed for operating the railway gates.

Semiautomatic railway gate operation is also followed in certain areas. Signals are located in the vicinity of the railway gate along with gate master board and a marker light.

It also should be noted that the information regarding the arrival and departure time of a particular train is done on the basis of distance between two station and average speed attained by the particular train and it is a usual cause that there will be, always some obstacles present in any part of railway network.

Problems caused due to maned and unmanned railway gate crossings 路 It is not possible to deploy a gate keeper in each and every railway crossings.If employed,huge amount should be invested and hence there is an increased burden for the passengers. 路 Severe loss of lives and huge damage will occur to the railway system if proper attention is not paid at unmanned railway gate crossings.

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CHAPTER 2

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communication to nearby station and also leads to huge loss of lives and damage to the whole railway system. · Huge amount should be invested to pay for each gate keeper for several years,in case of manned railway crossings.

Problems caused due to false timings in display and obstacles in railway tracks · Huge time was wasted by the passenger without knowing the arrival and departure time of a particular train due to false timings in the display. · Loss of communication will occur in absence of gate keeper at a manned railway crossing and this results in false timings in the display. · Huge loss of lives and damage will takes place ,if obstacles found in the railway tracks are not paid proper attention. · False timing in the displays will also occur,if the timing are done on the basis of predetermined value based on distance between two station and average speed attained by that particular train(This false timings will occur,if there is any obstacle in the track while that particular train moves from one station to another station) Problems caused due to dense snow and fog · Huge damage will be caused ,if proper attention in not paid by the train operator during dense snow and fog, while traveling from station to another station.

PROBLEM SOLVING Using this project ,we can overcome the problem of manned and unmanned railway crossings by means of automatic railway gate control mechanism and also the problem caused by the obstacles in the railway track and false timings in displays are overcome by means of ultrasonic sensing mechanism and GSM-R technique. The problem caused by dense snow and fog are overcomed with help of, the same ultrasonic sensing mechanism.

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· In absence of gate keeper at a manned railway crossing will result in loss of

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CONCLUSION Thus the various problems faced in the present day railway system are described in this chapter and proposed solution is also given.The description of the solution is given in the remaining chapters.

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CHAPTER 3

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BLOCK DIAGRAM OF THE PROJECT 3.1INTRODUCTION This chapter deals with the block diagram of the entire project,the components used,its function and a brief explanation about it.

3.2 BLOCK DIAGRAM

DC MOTOR

BUZZER

RS 232 IR SENSING aa UNIT

MICROCONTROLLER AT89C2051

GSM MODEM

CONTROL CENTRE

ULTRASONIC SENSING UNIT

LED DISPLAY

PC Fig3.1 Block Diagram Of The Entire Project

PASSENGER CELL PHONE

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3.3EXPLANATION Movement of train is sensed by the IR sensing unit and obstacles are detected by the ultrasonic sensing unit. Both these sensing unit will provide an interrupt signal to the microcontroller.The microcontroller used here is Atmel 89C2051.The description of this microcontroller will be discussed in the following chapter.once interrupt signal is received by the microcontroller,it will give control signal to DC motor and buzzer for automatic gate control mechanism and obstacle detection..similarly,data

transfer

will

occur

between GSM

modem

and

Microcontroller through RS-232 cable.The data’s from GSM modem are transferred as SMS directly to passenger cellphone or to controlcentre and from here,it will be send to led display and passenger cellphone. Here PC interfacing is used for programming in the Microcontroller using keil software.The description of ultrasonic sensing unit for obstacle detection,IR sensing unit for automatic gate control and the application of GSM modem will be discussed in the following chapter.

3.4CONCLUSION Here the block diagram of the entire project and the components used has been discussed in the above chapter.

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CIRCUIT DIAGRAM OF THE COMPONENTS 4.1 INTRODUCTION This chapter deals with the circuit diagram of the components and its brief explanation.

4.2 CIRCUIT DIAGRAM

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CHAPTER 4

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circuit diagram.Interfacing of microntroller with ultrasonic transmitter and receiver sensor circuit is shown below.

4.3 ULTRASONIC TRANSMITTER CIRCUIT

4.4 ULTRASONIC RECEIVER CIRCUIT

4.5 PROJECT SCHEMATIC DIAGRAM The above figure shows the overall circuit of our project. It consists of some important components. They are power circuit, microcontroller circuit(AT89C51), IR sensor circuit, Ultrasonic sensor circuit, GSM-Railway circuit and DC Shunt motor circuit.

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Interfacing of microcontroller with ultrasonic sensor is not shown in the above

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In our project microcontroller circuit plays an important role when compare to other circuit.AT89C51 is the controller circuit used in our project. It belongs to the 8051 family.

After receiving 5V DC supply, it starts to generate control signals. Suppose if the train crosses the IR sensor path it automatically generates 0V( i.e no rays across the track.

Now this voltage will be compared with the fixed voltage of the comparator gives an interrupt signal to the microcontroller circuit at the pin INT0(Interrupt-0).

After receiving interrupt signal from the comparator circuit it will perform two functions.

First it gives signal to the monolithic four channel driver circuit which accepts TTL signals to operate the DC shunt motor. Generally the driver circuit has pair of channels and each channel is enabled by separate supply received from TTL signals. The driver circuit is commonly operate at lower voltage because of internal clamp diodes. After completing the process in driver circuit it gives signal to the DC shunt motor which automatically control the gate.

Simultaneously it gives signal to the MAX232 circuit which is an integrated circuit which converts signals from an RS232 serial port to signals suitable for use in TTL compatible logic circuits. Finally it gives signal in the form of programming code to the GSM modem by making port3 pin as high. After accepting the signals from MAX232 it gives messages to the passengers those who registered and peoples in the railway station through SMS. Another function of microcontroller is to give signal to buzzer to alert the driver to prevent the accidents in the railway track. This can be achieved through the Ultrasonic sensor which is high sensitive to detect obstacles present in the railway track. Suppose if obstacles present in the railway track means then ultrasonic sensor gives interrupt signal to the microcontroller for its function. Once received the signal it gives signal to the buzzer to starts to ringing operation by this way the driver stop the train to prevent accidents.

4.7 IR SENSOR CIRCUIT IR Sensor circuit also plays an important role in railway network. It has two parts: one is IR transmitter and IR receiver. This two sensor will be kept across the railway track at

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4.6 MICROCONTROLLER CIRCUIT

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rays across the track. The output of this sensor will be compared with fixed voltage at the comparator circuit finally it gives a resultant signal which is less to operate the microcontroller. This can be achieved during normal operation (without train movement).

Suppose if the train crosses across the IR sensor it automatically gives 0V to the comparator circuit which gives resultant signal which is greater than the previous values. Therefore it gives interrupt signal to the microcontroller to perform its functions.

4.8 ULTRASONIC SENSOR CIRCUIT Ultrasonic sensor also an important component in railway network. This sensor is to detect obstacles present in the railway track. . It has two parts: one is Ultrasonic transmitter and Ultrasonic receiver. The Ultrasonic transmitter continuously transmits the Ultrasonic radiations across the track. During normal operation it gives signal to the comparator circuit which gives a resultant signal always less than the value of interrupt signal.

When obstacles present in the railway track it automatically reduces to zero therefore the resultant signal obtained from the comparator circuit is greater than the interrupt signal results in microcontroller was interrupted. Therefore the microcontroller gives signal to the buzzer to starts its operation. Once starts ringing the driver should identified the obstacles is their in track so that he stop the train at the instant. By this way railway accidents can be prevented.

4.9 GSM-RAILWAY CIRCUIT GSM-R also plays an important role in modern railway systems. The main function of GSM-R technology in railway network is to provide efficient data transfer to the passengers and peoples at the railway station regarding arrival and departure timings of railways. Therefore saving of time can be achieved. This can be done with the help of embedded program which is coded in the microcontroller circuit to starts sending SMS to the peoples after reaching interrupt signal from the IR sensor circuit.

4.9.0 DC SHUNT MOTOR CIRCUIT DC shunt motor also an important component in our project. It is operated by means of H-bridge L293D circuit. It is a four channel driver circuit which has pair of channels and

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some kilometer away from the station. The IR transmitter continuously transmits the IR

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microcontroller circuit through RS232 cables. After completing its function it gives signal to the DC shunt motor. This motor starts rotating first in clockwise direction after some milliseconds it starts rotating in anticlockwise direction to control the railway gates. The delay can be set according to the train movement and it is normally takes some time to change its direction.

POWER CIRCUIT DIAGRAM

FIG 4.9.1(B) POWER CIRCUIT

4.9.2 EXPLANATION 4.9.3 POWER CIRCUIT Fig 12.1(B) shows the power circuit diagram for our project. It consists of supply(12V AC),full bridge inverter, decoupling capacitors,12V regulators,5V regulators, double 2PIN RMC circuits and IR transmitter circuit.

Initially the circuit is energized by 12V AC supply and this voltage can be converted into 12V DC supply by means of full bridge inverter circuit. Two decoupling capacitors are used to filter the ripples present in the output of inverter. Next 12V regulator is used to regulate the filtered output to get pure DC voltage. During regulation if any ripples present in its output then it can be further filtered by means of 2PIN RMC circuit.

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each channel is separately enabled from the TTL signals received from the

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Now this supply is given to the 5V regulator which gives regulated output. Further if ripples present in its output it can be filtered by means of another 2PIN RMC circuit.

Since the microcontroller circuit requires only 5V DC therefore the output of RMC circuit is directly given to the controller circuit. In between these two circuits one main circuit is present as shown in Fig 12.1(B) which is known as IR Transmitter.

The IR Transmitter accepts the output of RMC circuit therefore it continuously transmits the signals as long as interruption is not present between sensors. The output of IR transmitter is 5V DC during normal operation and if interruption is present then the output reduces to 0V DC. Once this process arises suddenly the microcontroller circuit interrupts corresponding circuits.

CONCLUSION In this chapter the discussion about the various important components and their circuit diagrams are given

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After removing ripples from the input of RMC circuit the output becomes 5V DC supply.

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CHAPTER 5

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INTRODUCTION TO MICROCONTROLLER 5.1 INTRODUCTION This chapter deals about the imporatance of microcontroller and the role played by the microcontroller in our project.

5.2 DESCRIPTION TO EMBEDDED CONTROLLER Microcontroller, as the name suggests, are small controllers. These are like single chip computers that are often embedded into systems to function as processing /controllers unit. For example, the remote control you are using probably has microcontrollers inside that do decoding and other controlling functions. They are also used in automobiles, washing machines, microwave ovens, toys…etc, where automation is needed. The key features of microcontrollers include: • High integration of Functionality Microcontrollers sometimes are called single chip computers because they have on-chip memory and I/O circuitry and other circuitries that enable them to function as small standalone computers without other supporting circuitry.

• Field Programmability, Flexibility Microcontrollers often use EEPROM or EPROM as their storage device to allow field programmability so they are flexible to use. Once the

program is tested to be

correct then large quantities of microcontrollers can be programmed to be used in embedded systems.

• Easy to Use Assembly language is often used in microcontroller and since they usually follow RISC architecture, the instruction set is small. The development package of microcontrollers often includes an assembler ,a simulator ,a programmer to “ burn “ the chip and a demonstration board .Some packages include a high level language compiler such as a C compiler and more sophisticated libraries.

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FIG 5.2 CONTROLLER BLOCK DIAGRAM

The main units of a microcontroller are discussed below:-

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5.3MEMORY UNIT

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Memory is part of the microcontrollers whose function is to store data.

The easiest way to explain it is to describe it as one big closet with lots of drawers. If we suppose that we marked the drawers in such a way that they can not be confused, any of their contents will then be easily accessible. It is enough to know the designation of the drawer and so its contents will be know to us for sure.

FIG 5.3 MEMORY UNIT OF MICROCONTROLLER

Memory components are exactly like that. For a certain input we get the contents of a certain addressed memory location and that’s all. Two new concepts are brought to us: addressing and memory location. Memory consists of all memory locations, and addressing is nothing but selecting one of them. This means that we need to select the desired memory location on one hand, and on the other hand we need to wait for the contents of that location.

Besides reading from a memory location, memory must also provide for writing onto it. This is done by supplying an additional line called control line. We will designate this line as R/W (read/write). Control line used in the following way: if r/w=1, reading is done, and if opposite

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is true then writing is done on the memory location. Memory is the first element, and we need w w C

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a few operation of our microcontroller.

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5.4 CENTRAL PROCESSING UNIT Let add three memory locations to a specific block that will have a built in capability to multiply, divide, subtract, and move its contents from one memory location onto another. The part we just in is called “Central Processing Unit” (CPU). Its memory locations are called registers.

FIG 5.4 CENTRAL PROCESSING UNIT OF MICROCONTROLLER

Registers are therefore memory locations whose role is to help with performing various mathematical operations or any other operations with data wherever data can be found. Look at the current situation. We have two independent entities (memory and CPU) which are interconnected, and thus any exchange of data is hindered, as well as its functionality. If, for example, we wish to add the contents of two memory locations and return the result again back to memory, we would need a connection between memory and CPU. Simply stated, we must have some “way” though data goes from one block to another.

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5.5 INPUT-OUTPUT UNIT

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Those locations we’ve just added are called “ports”. There are several types of ports: Input, output or bidirectional ports. When working with ports, first of all it is necessary to choose which port we need to work with, and then to send data to, or take it from the port.

FIG 5.5 INPUT-OUTPUT UNIT OF MICROCONTROLLER

When working with it the port acts like a memory location. Something is simply being written into or read from it, and it could be noticed on the pins of the microcontroller.

5.6 SERIAL COMMUNICATION: Beside stated above we’ve added to the already existing unit the possibility of communication with an outside world. However, this way of communicating has drawbacks.

One of the basic drawbacks is the number of lines which need to be used in order to transfer data. What if it is being transferred to a distance of several kilometers? The number of lines time’s numbers of kilometers doesn’t promise the economy of the project. It leaves us having to reduce the number of lines in such a way that we don’t lessen its functionality.

Suppose we are working with three lines only, and that one line is used for sending data ,other for receiving, and the third one is used as a reference line for both the input and output side. In order for this to work, we need to set the rules of exchange of data. These rules are

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called protocol. Protocol is therefore defined in advance so there wouldn’t be any w w C

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misunderstanding between the sides that are communicating with each other. The logical unit “1” is set up on the transmitting line until transfer begins.

Once the transfer starts, we lower the transmission line to logical ‘0” for a period of time (which we will designate as T), so the receiving side will know that it is receiving data, and so it will activate its mechanism for reception. Let’s go back now to the transmission side and

start putting logic zeros and ones the transmitter line in the order from a bit of the lowest value to a bit of the highest value. Let each bit stay on line for a time period which is equal to T, and in the end, or after the 8th bit. Let us bring the logical unit “1” back on the line which will mark the end of the transmission of one data. The protocol we’ve just described is called in professional literature NRZ (Non-Return to Zero).

FIG5.6 SERIAL COMMUNICATION

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As we have separate lines for receiving and sending, it is possible to receiving and w w

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sends data at the same time. So called full-duplex mode block which enables this way of communication is called a serial communication block.

Unlike the parallel transmission, data moves here bit by bit, or in a series of bits what defines the term serial communication comes from. After the reception of data we need to read it from the receiving location and store it in memory as opposed to sending where the process is reversed. Data goes from memory through the buys to the sending location, and then to the receiving unit according unit according to the protocol.

5.7 TIMER UNIT Since we have the serial communication explained, we can receive, send and Process data.

FIG5.7 TIMER

However, in order to utilize it in industry we need a few additionally blocks. One of those is the timer block which is significant to us because it can give us information about time, duration, protocol etc. The basic unit of the timer is a free-run counter which is in fact a register whose numeric value increments by one in even intervals, so that by taking its value during periods T1 and T2 and on the basis of their difference we can determine how much time has elapsed. This is a very important part of the microcontroller whose understanding requires most of our time.

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CONCLUSION A detailed explanation of the Microcontroller has been given in this chapter.Also various components associated with the Microcontroller is also explained in the above chapter.

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DESCRIPTION OF TARGET PROCESSOR

6.1 INTRODUCTION This chapter deals with the description of the microcontroller AT89C2051,the

pin details of the same is also described in this chapter.

6.2FEATURES • Compatible with MCS®-51Products • 2K Bytes of Reprogrammable Flash Memory - Endurance: 10,000 Write/Erase Cycles • 2.7V to 6V Operating Range • Fully Static Operation: 0 Hz to 24 MHz • Two-level Program Memory Lock • 128 x 8-bit Internal RAM • 15 Programmable I/O Lines • Two 16-bit Timer/Counters • Six Interrupt Sources • Programmable Serial UART Channel • Direct LED Drive Outputs • On-chip Analog Comparator • Low-power Idle and Power-down Modes • Green (Pb/Halide-free) Packaging Option

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6.3 DESCRIPTION The AT89C2051

is

a

low-voltage,

high-performance

CMOS

8-bit

microcomputer with 2K bytes of Flash programmable and erasable read-only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.

The AT89C2051 provides the following standard features: 2K bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, onchip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.

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6.4 BLOCK DIAGRAM OF MICROCONTROLLER

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6.5 PIN DIAGRAM OF MICROCONTROLLER

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PIN DESCRIPTION

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Supply voltage Ground

PORT 1 The Port 1 is an 8-bit bi-directional I/O port. Port pins P1.2 to P1.7 provide internal pull-ups. P1.0 and P1.1 require external pull-ups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the onchip precision analog comparator. The Port 1 output buffers can sink 20 mA and can drive LED displays directly. When 1s are written to Port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally pulled low, they will source current (IIL) because of the internal pullups.Port 1 also receives code data during Flash programming and verification PORT 2 Port 3 pins P3.0 to P3.5, P3.7 are seven bi-directional I/O pins with internal pull-ups. P3.6 is hardwired as an input to the output of the on-chip comparator and is not accessible as a general-purpose I/O pin. The Port 3 output buffers can sink 20 mA. 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.

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listed below: Port Pin P3.0 P3.1 P3.2 P3.

3 P3.5

Alternate Functions RXD (serial input port) TXD (serial output port) INT0 (external interrupt 0) INT1 (external interrupt 1) T0 T1 (timer 1 external input)

RST Reset input. All I/O pins are reset to 1s as soon as RST goes high. Holding the RST pin high for two machine cycles while the oscillator is running resets the device.

Each machine cycle takes 12 oscillator or clock cycles XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

SPECIAL FUNCTION REGISTERS A map of the on-chip memory area called the Special Function Register (SFR).

Note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general return random data, and write accesses will have an indeterminate effect.

User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that case, the reset or inactive values of the new bits will always be 0.

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Port 3 also serves the functions of various special features of the AT89C2051 as

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priorities can be set for each of the six interrupt sources in the IP register.

DATA MEMORY The AT89C51implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel address space to the Special Function Registers. That means the upper 128 bytes have the same addresses as the SFR space but are physically separate from SFR space.

When an instruction accesses an internal location above address 7FH, the address mode used in the instruction specifies whether the CPU accesses the upper 128 bytes of RAM or the SFR space. Instructions that use direct addressing access SFR space.

For example, the following direct addressing instruction accesses the SFR at location 0A0H (which is P2).

Instructions that use indirect addressing access the upper 128 bytes of RAM. For example, the following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).

MOV @R0, #data Note that stack operations are examples of indirect addressing, so the upper 128 bytes of data RAM are available as stack space.

TIMER 0 AND 1 Timer 0 and timer 1 in the AT89C52 operate the same way as timer 0 and timer 1 in the AT89C51.

TIMER 2 Timer 2 is a 16-bit Timer/counter that can operate as either a timer or an event counter.

The type of operation is selected by bit C/T2 in the SFR T2CON (shown in table 2).

Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate generator. The modes are selected by bits in T2CON, as shown in Table 3.

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Timer 2 Registers The individual interrupt enable bits are in the IE register. Two

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register is incremented every later periods, the count rate is 1/12 of the oscillator frequency.

In the counter function, the register is incremented in response to a 1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count is incremented.

The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are required to recognize a 1-to-0 transition, the maximum count rate is 1/24 of the oscillator frequency. To ensure that a given level should be held for at least one full machine cycle

CONCLUSION The detailed explanation of the Microcontroller AT89C2051 has been given in this chapter.Also various ports of the microcontroller is also explained in the above chapter.

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Timer 2 consists of two 8-bit registers, TH2 and TL2. In the Timer function, the Tl2

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AUTOMATIC GATE CONTROL USING IR SENSORS 7.1 INTRODUCTION This chapter deals with automatic control of railway crossing gate using IR sensors and various components involved in the control mechanism and its application.

7.2 GENERAL DESCRIPTION An automatic control system is an arrangement of physical components connected in such a manner so as to direct or regular itself or some another system i.e. some controlled condition forming part of the system is maintained in a prescribed manner.

Automatic control system have influenced the current way of life. In recent year automatic control systems have been rapidly increasing importance in all fields of engineering. Its application covers a very wide range from design of precision control devices to design of massive equipments used for manufacture of steel and other industries.

Present project is designed using 8051 microcontroller to avoid railway accidents happening at unattended railway gates, if implemented in spirit. This project utilizes two powerful IR transmitters and two receivers; one pair of transmitter and receiver is fixed at up side (from where the train comes) at a level higher than a human being in exact alignment and similarly the other pair is fixed at down side of the train direction. Sensor activation time is so adjusted by calculating the time taken at a certain speed to cross at least one compartment of standard minimum size of the Indian railway. We have considered 5 seconds for this project.

Sensors are fixed at 1km on both sides of the gate. We call the sensor along the train direction as ‘foreside sensor’ and the other as ‘aft side sensor’. When foreside receiver gets activated, the gate motor is turned on in one direction and the gate is closed and stays closed until the train crosses the gate and reaches aft side sensors.

When aft side receiver gets activated motor turns in opposite direction and gate opens and motor stops. Buzzer will immediately sound at the fore side receiver activation and

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avoid trapping between the gates and stop sound after the train has crossed.

7.3 COMPONENTS INVOLVED IN AUTOMATIC GATE CONTROL MECHANISM ·

IR SENSOR(LED)

·

LOW

POWER

QUAD

OPERATIONAL AMPLIFIER(LM324) ·

TRIMMER

·

PUSH

PULL

FOUR

MOTOR

(FOR

CHANNEL DRIVER WITH DIODES(L293D) ·

DC CLOSING AND OPENING OF GATE)

7.4 IR SENSOR INFRARED Infrared (IR) radiation is electromagnetic radiation whose wavelength is longer than that of visible light (400-700 nm), but shorter than that of terahertz radiation (100 µm - 1 mm) and microwaves (~30,000 µm). Infrared radiation spans roughly three orders of magnitude (750 nm and 100 µm).

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared (47% share of the spectrum), visible (46%), and ultra-violet (only 6%) light. Bright sunlight provides luminance of approximately .

LIGHT-EMITTING DIODE A light-emitting diode (LED) is an electronic light source. The LED was first invented in Russia in the 1920s, and introduced in America as a practical electronic component in 1962. Oleg Vladimirovich Losev was a radio technician who noticed

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gate will close after 5 seconds, so giving time to drivers to clear gate area in order to

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them. In 1927, he published details in a Russian journal of the first ever LED. All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness.

LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection.[2] LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources.

Applications of LEDs are diverse. They are used as low-energy indicators but also for replacements for traditional light sources in general lighting and automotive lighting. The compact size of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are useful in communications technology.

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that diodes used in radio receivers emitted light when current was passed through

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PARTS OF AN LED

Like a normal diode, the LED consists of a chip of semiconducting material impregnated, or doped, with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.

The wavelength of the light emitted, and therefore its color, depends on the band gap energy of the materials forming the p-n junction. In silicon or germanium diodes, the electrons and holes recombine by a non-radiative transition which produces no optical emission, because these are indirect band gap materials. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.

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arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors.

LEDs are usually built on an n-type substrate, with an electrode attached to the ptype layer deposited on its surface. P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate.

Most materials used for LED production have very high refractive indices. This means that much light will be reflected back in to the material at the material/air surface interface. Therefore Light extraction in LEDs is an important aspect of LED production, subject to much research and development

COLORS AND MATERIALS Conventional LEDs are made from a variety of inorganic semiconductor materials, the following table shows the available colors with wavelength range, voltage drop and material: Color

Wavelength [nm]

Infrared λ > 760

Voltage [V]

ΔV < 1.9

Semiconductor Material Gallium

arsenide

(GaAs)

Aluminum gallium arsenide (AlGaAs) Aluminium gallium arsenide (AlGaAs)

Red

610 < λ < 760

1.63 < ΔV < 2.03

Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP) Gallium(III) phosphide (GaP)

Orange 590 < λ < 610

LED as light sensor

2.03 < ΔV <

Gallium arsenide phosphide (GaAsP)

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LED development began with infrared and red devices made with gallium

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properties of light emitting diodes (LEDs) can be exploited to render them useful for light detection as well as emission. This capability has been demonstrated and used in a variety of applications including ambient light detection and bidirectional communications. This implementation of LEDs is important because functionality can be added to designs with only minor modifications, usually at little or no cost.

Technical description An LED is simply a diode that has been doped specifically for efficient light emission and has been packaged in a transparent case. Therefore, if inserted into a circuit in the same way as a photodiode, which is essentially the same thing, the LED will perform the same function. As a photodiode, it is sensitive to wavelengths equal to or shorter than the predominant wavelength it emits. For example, a green LED will be sensitive to blue light and to some green light, but not to yellow or red light. Additionally, the LED can be multiplexed in such a circuit, such that it can be used for both light emission and sensing at different times. In Dietz et al, a scheme for implementing this multiplexing is presented.

An LED is connected to two bidirectional CMOS I/O pins on a microcontroller (or a microprocessor with an I/O bus).

To emit light, both of the I/O pins are set to output mode, and the LED is driven with current in the forward direction, resulting in current through the LED and emission of light.

To detect ambient light: 路 The I/O pins are set to output mode, and the diode is driven in the reversebias direction, such that the diode inhibits the current and the LED's inherent capacitor is charged.

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An LED light sensor is a light-emitting diode used as a photodiode. The

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路 The diode leaks current at a rate proportional to the incident light, as incident photons cause electrons to leap across the band gap. 路 The time it takes for this leakage current to discharge the LED's inherent capacitor is measured and is inversely proportional to the incident light.

TRACK DETECTOR CIRCUIT In the circuit bellow the LED will turn on when the infrared beam is broken. The value of the resistor R1 determines the sensitivity of the phototransistor Q1. In most cases a value of 1 Meg or 470K ohm with good results but every situation is different and some experimentation might be needed.

Basic Infrared Detector Schematic CIRCUIT OPERATION

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路 The I/O pins are set to high-impedance CMOS input mode.

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voltage at the MINUS input of the comparator will rise above the reference voltage at the PLUS as determined by R3 and R4. The output of the comparator to turn ON and the LED will be lit.

EMITTER/DETECTOR ALIGNMENT Good alignment of the emitter and detector is important for good operation, especially if the gap is large. This can be done with a piece of string stretched between and in line with LED and phototransistor. A length of dowel or stiff wire could be used to set the alignment. Another method that can be used for longer distances is a laser pointer shone through one of the mounting holes.

The next diagram shows two methods of aligning the emitter and detector mountings. For best results the height of the "beam" should be at coupler height and at an angle across the tracks.

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When a train breaks the infrared beam the phototransistor will conduct less current. The

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EMITTER/DETECTOR ALIGNMENT METHODS The emitter could also be mounted above the track with the phototransistor placed between the rails in locations such as hidden yards. Placing the emitter and detector at an angle would again be helpful.

PHOTOTRANSISTOR SHIELDING Most infrared phototransistors are also sensitive to visible light and therefore will need to be shielded in someway to prevent the device from being swamped by the rooms lighting. This can be done by hiding the phototransistor inside a lineside structure or placing it inside a short piece of opaque tubing as shown below. The back of the phototransistor can be painted black to prevent room light from entering if it is in the open.

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Detector Shielding Method The longer the length of tubing the narrower the entrance angle to the phototransistor. The tubing can be clamped in place or mounted through a hole drilled in a small block of wood or plastic. The emitter does not need to be shielded unless its beam can affect another phototransistor nearby.

LOW POWER QUAD OPERATIONAL AMPLIFIER

7.1 GENERAL DESCRIPTION:

The LM3234 plays an crucial role in detector circuit.It acts as a comparator and compares the two input and produce an output which is proportional to difference between the two input voltage.

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compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.

Application areas include transducer amplifiers, DC gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM324 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional +15V and -15V power supplies.

7.2 UNIQUE CHARACTERISTICS: ·

In the linear mode the input common-mode voltage range includes ground and the output voltage can also swing to ground, even though operated from only a single power supply voltage

·

The unity gain cross frequency is temperature compensated

·

The input bias current is also temperature compensated

7.3 ADVANTAGES: ·

Eliminates need for dual supplies

·

Four internally compensated op amps in a single package

·

Allows directly sensing near GND and VOUT also goes to GND

·

Compatible with all forms of logic

·

Power drain suitable for battery operation

7.4 FEATURES: ·

Internally frequency compensated for unity gain

·

Large DC voltage gain 100 dB

·

Wide bandwidth(unity gain) 1 MHz (temperature compensated)

·

Wide power supply range: §

Single supply 3V to 32V

§

Or dual supplies +1.5V to +1.6V and -1.5V to -1.6V

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The LM324 series consists of four independent, high gain, internally frequency

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·

Very low supply current drain (700 microamps)-essentially independent of supply voltage

·

Low input biasing current 45 nA(temperature compensated)

·

Low input offset voltage 2 mV and offset current 5 nA

·

Input common-mode voltage range includes ground

·

Differential input voltage range equal to the power supply voltage Large output voltage swing 0V to V+ - 1.5V FIG 7.4 LM324 CONNECTION DIAGRAM(TOP VIEW) DUAL-IN-LINE PACKAGE

TRIMMER

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A trimmer is a miniature adjustable electrical component. It is meant to be set correctly when installed in some device, and never seen or adjusted by the device's user. Trimmers can be variable resistors (potentiometers) or variable capacitors. They are common in precision circuitry like A/V components, and may need to be adjusted when the equipment is serviced.

Unlike other variable controls, trimmers are mounted directly on circuit boards, turned with a small screwdriver and rated for many fewer adjustments over their lifetime.

TRIMMER IN DETECTOR CIRCUIT

Here the trimmer provides a stable output and this stable is usually set to 5volts.This stable output is obtained by adjusting resistance of the trimmer and this stable output is compared with IR sensor output in the comparator circuit and an output is provided to the Microcontroller depending on the difference between two inputs of comparator(LM324) i.e in terms of oâ&#x20AC;&#x2122;s or 1â&#x20AC;&#x2122;s.

L293D

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PUSH-PULL FOUR CHANNEL DRIVER WITH DIODES INTRODUCTION The L293D is a 16-pin integrated circuit (the surface mount version is 20pin)designed to drive loads such as motors,relays and solenoids.It sports four separate drivers and can be used as an H-brdige for two motors (each motors uses two of the chip’s output).The “D”suffix means that the IC has built-in clamping diodes on its outputs.these clamping diodes help prevent electrical damage when driving an inductive load.

8.2 KEY FEATURE ·

600mA output current capability per channel

·

1.2A peak output current(non repetitive) per channel

·

Enable facility

·

Overtemperature protection

·

Logical “0” input voltage up to 1.5 V (high noise immunity)

·

Internal clamp diodes

8.3 DESCRIPTION The Device is a monolithic integrated high voltage, high current four channel driver designed to accept standard DTL or TTL logic levels and drive inductive loads(such as relays, solenoides, DC motors and stepping motors) and switching power transistors.

To simplify use as two bridges each pair of channels is equipped with an enable input.

A separate supply input is provided for the logic, allowing operation at a lower voltage and internal clamp diodes are included.

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The L293D has two supply voltage:one for the logic portion of the chip and one for the driver output portion.The logic voltage and driver output voltage can be 4.5 to 36 volts,though the driver output voltage cannot be any less than the logic voltage(that is,if the logic voltage is 5 volts,thatâ&#x20AC;&#x2122;s the minimum for the driver output as well).

With a small heat sink,the L293D can handle loads of up to 600 milliamps per channel,with a peak draw of 1.2 amps.This isnâ&#x20AC;&#x2122;t enough for large motors on combat robots,of course,but itâ&#x20AC;&#x2122;s sufficient for the typical small carpet-roving bot.

Higher current carrying is possible merely by stacking two L293D chips on top of one another-just be sure to provide a good heat sink.Another option is to use the L293 and L293B provide an example schematic on how to do this.

This device is suitable for use in switching applications at frequencies up to 5 kHz. The L293D is assembled in a 16 lead plastic package which has 4 center pins connected together and used for heatsinking The L293DD is assembled in a 20 lead surface mount which has 8 center pins connected together and used for heatsinking.

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BLOCK DIAGRAM FIG 8.1 BLOCK DIAGRAM

DC MOTOR INTERFACING WITH MICROCONTROLLERS

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10.1 INTRODUCTION Whenever a robotics hobbyist talk about making a robot, the first thing comes to his mind is making the robot move on the ground. And there are always two options in front of the designer whether to use a DC motor or a stepper motor. When it comes to speed, weight, size, cost... DC motors are always preffered over stepper motors.

There are many things which you can do with your DC motor when interfaced with a microcontroller. For example you can control the speed of motor, you can control the direction of rotation, you can also do encoding of the rotation made by DC motor i.e. keeping track of how many turns are made by your motors etc.

In this part of tutorial we will learn to interfacing a DC motor with a microcontroller.

Usually H-bridge is preffered way of interfacing a DC motor. These days many IC manufacturers have H-bridge motor drivers available in the market like L293D is most used H-Bridge driver IC. H-bridge can also be made with the help of trasistors and MOSFETs etc. rather of being cheap, they only increase the size of the design board, which is somtimes not required so using a small 16 pin IC is preffered for this purpose.

10.2 WORKING THEORY OF H-BRIDGE The name "H-Bridge" is derived from the actual shape of the switching circuit which control the motion of the motor. It is also known as "Full Bridge". Basically there are four switching elements in the H-Bridge as shown in the figure below.

FIG 10.2(A) SWITCHING CIRCUIT OF DC MOTOR(FORWARD DIRECTION)

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As you can see in the figure above there are four switching elements named as "High side left", "High side right", "Low side right", "Low side left". When these switches are turned on in pairs motor changes its direction accordingly. Like, if we switch on High side left and Low side right then motor rotate in forward direction, as current flows from Power supply through the motor coil goes to ground via switch low side right. This is shown in the figure below.

FIG 10.2(B) SWITCHING CIRCUIT OF DC MOTOR(BACKWARD DIRECTION)

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opposite direction and motor rotates in backward direction. This is the basic working of H-Bridge. We can also make a small truth table according to the switching of H-Bridge explained above.

Truth Table High Left

High Right

Low Left

Low Right

Description

On

Off

Off

On

Motor runs clockwise

Off

On

On

Off

Motor runs anti-clockwise

On

On

Off

Off

Motor stops or decelerates

Off

Off

On

On

Motor stops or decelerates

As already said, H-bridge can be made with the help of trasistors as well as MOSFETs, the only thing is the power handling capacity of the circuit. If motors are needed to run with high current then lot of dissipation is there. So head sinks are needed to cool the circuit.

So we have seen that using simple switching elements we can make our own H-Bridge, or other option we have is using an IC based H-bridge driver. Both of them are discussed in the next section of the tutorial.

10.3 L293D DUAL H-BRIDGE MOTOR DRIVER

L293D is a dual H-Bridge motor driver, So with one IC we can interface two DC motors which can be controlled in both clockwise and counter clockwise direction and if you have motor with fix direction of motion the you can make use of all the four I/Os to connect up to four DC motors. L293D has output current of 600mA and peak output current of 1.2A per channel. Moreover for protection of circuit from back EMF ouput diodes are included within the IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has made L293D a best choice for DC motor driver.

A simple schematic for interfacing a DC motor using L293D is shown below.

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Similarly, when you switch on low side left and high side right, the current flows in

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As you can see in the circuit, three pins are needed for interfacing a DC motor (A, B, Enable). If you want the o/p to be enabled completely then you can connect Enable to VCC and only 2 pins needed from controller to make the motor work

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FIG 10.3 DC MOTOR USING L293D

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GATE CONTROL

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Railways being the cheapest mode of transportation are preferred over all the other means .When we go through the daily newspapers we come across many railway accidents occurring at unmanned railway crossings. This is mainly due to the carelessness in manual operations or lack of workers. We, in this project has come up with a solution for the same. Using simple electronic components we have tried to automate the control of railway gates. As a train approaches the railway crossing from either side, the sensors placed at a certain distance from the gate detects the approaching train and accordingly controls the operation of the gate. Also an indicator

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CONCLUSION Thus detailed explanation of automatic control of railway crossing gate using IR sensors and various components involved in the control mechanism are discussed in the above chapter.

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CHAPTER 8 OBSTACLE DETECTION USING ULTRASONIC SENSOR INTRODUCTION This chapter deals with obstacle detection at railway track using ultrasonic sensor and various components involved in the sensing mechanism and its application GENERAL DESCRIPTION ULTRASONICS The term ultrasonics applies to sound waves that vibrate at a frequency higher than the frequency that can be heard by the human ear (or higher than about 20,000 hertz).

Sound is transmitted from one place to another by means of waves. The character of any wave can be described by identifying two related properties: its wavelength (indicated by the Greek letter lambda, 位) or its frequency (f). The unit used to measure the frequency of any wave is the hertz (abbreviation: Hz). One hertz is defined as the passage of a single wave per second.

Ultrasonics, then, deals with sound waves that pass a given point at least 20,000 times per second. Since ultrasonic waves vibrate very rapidly, additional units also are used to indicate their frequency. The kilohertz (kHz), for example, can be used to measure sound waves vibrating at the rate of 1,000 (kilo means 1,000) times per second, and the unit megahertz (MHZ) stands for a million vibrations per second. Some ultrasonic devices have been constructed that produce waves with frequencies of more than a billion hertz.

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for humansâ&#x20AC;&#x201D;that is, greater than about 20 kilohertz. The term sonic is applied to ultrasound waves of very high amplitudes. Hypersound, sometimes called praetersound or microsound, is sound waves of frequencies greater than 1013 hertz. At such high frequencies it is very difficult for a sound wave to propagate efficiently; indeed, above a frequency of about 1.25 Ă&#x2014; 1013 hertz, it is impossible for longitudinal waves to propagate at all, even in a liquid or a solid, because the molecules of the material in which the waves are traveling cannot pass the vibration along rapidly enough.

PRODUCTION OF ULTRASONIC WAVES

The general principle involved in generating ultrasonic waves is to cause some dense material to vibrate very rapidly. The vibrations produced by this material than cause air surrounding the material to begin vibrating with the same frequency.

These vibrations then spread out in the form of ultrasonic waves.

TRANSDUCERS An ultrasonic transducer is a device used to convert some other type of energy into an ultrasonic vibration. There are several basic types, classified by the energy source and by the medium into which the waves are being generated. Mechanical devices include gas-driven, or pneumatic, transducers such as whistles as well as liquid-driven transducers such as hydrodynamic oscillators and vibrating blades.

These devices, limited to low ultrasonic frequencies, have a number of industrial applications, including drying, ultrasonic cleaning, and injection of fuel oil into burners. Electromechanical transducers are far more versatile and include piezoelectric and magnetostrictive devices.

A magnetostrictive transducer makes use of a type of magnetic material in which an applied oscillating magnetic field squeezes the atoms of the material together, creating a periodic change in the length of the material and thus producing a high-frequency mechanical vibration. Magnetostrictive transducers are

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vibrations of frequencies greater than the upper limit of the audible range

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cleaners and ultrasonic machining applications.

By far the most popular and versatile type of ultrasonic transducer is the piezoelectric crystal, which converts an oscillating electric field applied to the crystal into a mechanical vibration. Piezoelectric crystals include quartz, Rochelle salt, and certain types of ceramic. Piezoelectric transducers are readily employed over the entire frequency range and at all output levels. Particular shapes can be chosen for particular applications. For example, a disc shape provides a plane ultrasonic wave, while curving the radiating surface in a slightly concave or bowl shape creates an ultrasonic wave that will focus at a specific point.

Piezoelectric and magnetostrictive transducers also are employed as ultrasonic receivers, picking up an ultrasonic vibration and converting it into an electrical oscillation.

ULTRASONIC RANGE FINDING

A common use of ultrasound is in range finding; this use is also called SONAR, (sound navigation and ranging). This works similarly to RADAR (radio detection and ranging): An ultrasonic pulse is generated in a particular direction. If there is an object in the path of this pulse, part or all of the pulse will be reflected back to the transmitter as an echo and can be detected through the receiver path. By measuring the difference in time between the pulse being transmitted and the echo being received, it is possible to determine how far away the object is.

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used primarily in the lower frequency ranges and are common in ultrasonic

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the temperature and the salinity of the water. Ultrasonic ranging is also applied for measurement in air and for short distances. Such method is capable for easily and rapidly measuring the layout of rooms.

Although range finding underwater is performed at both sub-audible and audible frequencies for great distances (1 to several ten kilometers), ultrasonic range finding is used when distances are shorter and the accuracy of the distance measurement is desired to be finer. Ultrasonic measurements may be limited through barrier layers with large salinity, temperature or vortex differentials.

Ranging in water varies from about hundreds to thousands of meters, but can be performed with centimeters to meters accuracy.

COMPONENTS INVOLVED IN ULTRASONIC SENSOR FOR OBSTACLE DETECTION · ULTRASONIC SENSOR · 555TIMER( MULTIVIBRATOR) · LOWER POWER QUAD OPERATIONAL AMPLIFIER · TRIMMER (Since low power quad operational amplifier and trimmer are already discussed here we are going to discuss about ultrasonic sensor and 555 timer only)

GENERAL DESCRIPTION FOR ULTRASONIC SENSOR ultrasonic distance sensor provides precise, non-contact distance measurements from about 2 cm (0.8 inches) to 3 meters (3.3 yards). It is very easy to connect to microcontrollers such as the BASIC Stamp®, SX or Propeller chip, requiring only one I/O pin.

The PING))) sensor works by transmitting an ultrasonic (well above human hearing range) burst and providing an output pulse that corresponds to the time

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The measured travel time of SONAR pulses in water is strongly dependent on

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width, the distance to target can easily be calculated.

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required for the burst echo to return to the sensor. By measuring the echo pulse

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FEATURES OF PING SENSOR

Range: 2 cm to 3 m (0.8 in to 3.3 yd) Burst indicator LED shows sensor activity Bidirectional TTL pulse interface on a single I/O pin can communicate with 5 V TTL or 3.3 V CMOS microcontrollers Input trigger: positive TTL pulse, 2 µs min, 5 µs typ.

Echo pulse: positive TTL pulse, 115 µs minimum to 18.5 ms maximum.

KEY SPECIFICATION FOR PING SENSOR

• Supply voltage: +5 VDC • Supply current: 30 mA typ; 35 mA max • Communication: Positive TTL pulse • Package: 3-pin SIP, 0.1” spacing (ground, power, signal) • Operating temperature: 0 - 70° C. • Size: 22 mm H x 46 mm W x 16 mm D (0.84 in x 1.8 in x 0.6 in) • Weight: 9 g (0.32 oz) Pin Definitions

GND 5V SIG

Ground (Vss) 5 VDC (Vdd) Signal (I/O pin)

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The PING))) sensor has a male 3-pin header used to supply ground, power (+5 VDC) and signal. The header may be plugged into a directly into solderless breadboard, or into a standard 3-wire extension cable ULTRASONIC SENSOR CIRCUIT The ultrasonic proximity detector comprising independent, battery-powered transmitter and receiver sections makes use of a pair of matched ultrasonic piezoceramic transducers operating at around 40 kHz each.

CONSTRUCTION FIG 11.2(A) TRANSMITTER CIRCUIT

Fig. 11.2(A) shows the transmitter circuit. It comprises CMOS timer IC 7555(IC1) configured as an astable multivibrator, which may be tuned to the frequency of the ultrasonic peizoceramic transmitterâ&#x20AC;&#x2122;s resonant frequency of around 40 kHz using preset VR1. A complementary pair of transistors T1 and T2 is used for driving and buffering the

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transducer while it draws wide bandwidth and very low bias current apart from being capable of single-supply operation. Quad op-amp LM324 is used here due to its low cost. For higher efficiency, you may use single op-amps such as CA3130 or CA3140.

When a visitor pauses before a spikes of current from IC1 circuit to sustain oscillations and thereby avoids any damage.

FIG 11.2(B) RECEIVER CIRCUIT

The receiver front-end(refer Fig.11.2(B)) is designed to provide a very high gain for the reflected faint ultrasonic frequency signals detected by the ultrasonic transducer. The amplifiers built around N1 and N2, respectively, provide AC voltage gain of around 80 each. These two stages should have a high open-circuit gain, product, it signifies his interest. Switching diode D1 followed by a filter comprising capacitor C5 and resistor R10 is used to meet this requirement. The filter also helps to bypass brief bursts of ambient noise in the ultrasonic range. The third stage comprising N3 works as a comparator to provide a triggering pulse when a visitor stops by. This pulse can be used to trigger a timer or a monostable, whose output may then be used to switch on the audio/video message concerning the product for a predetermined period.

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555 TIMER (MULTIVIBRATOR)

GENERAL DESCRIPTION The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications. The IC was designed and invented by Hans R. Camenzind. It was designed in 1970 and introduced in 1971 by Signetics (later acquired by Philips). The original name was the SE555/NE555 and was called "The IC Time Machine".[1] The 555 gets its name from the three 5-m resistors used in typical early implementations. It is still in wide use, thanks to its ease of use, low price and good stability. As of 2003, 1 billion units are manufactured every year Depending on the manufacturer, it includes over 20 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8).

The 556 is a 14-pin DIP that combines two 555s on a single chip.

The 558 is a 16-pin DIP that combines four slightly modified 555s on a single chip (DIS & THR are connected internally, TR is falling edge sensitive instead of level sensitive).

Also available are ultra-low power versions of the 555 such as the 7555 and TLC555.The 7555 requires slightly different wiring using fewer external components and less power.

The 555 has three operating modes: Monostable mode: in this mode, the 555 functions as a "one-shot". Applications include timers, missing pulse detection, bouncefree switches, touch switches, Frequency Divider,Capacitance Measurement, Pulse Width Modulation (PWM) etc

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Astable - Free Running mode: the 555 can operate as an oscillator. Uses include LED and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse position modulation, etc.

Bistable mode or Schmitt trigger: the 555 can operate as a flip-flop, if the DIS pin is not connected and no capacitor is used. Uses include bouncefree latched switches, etc INTERNAL SCHEMATICS OF 555TIMER

.

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PIN DIAGRAM

The connection of the pins is as follows: Nr. Name

Purpose

1

GND

Ground, low level (0V)

2

TR

A short pulse high â&#x2020;&#x2019; low on the trigger starts the timer

3

Q

During a timing interval, the output stays at +VCC

4

R

5

CV

Control voltage allows access to the internal voltage divider (2/3 VCC)

6

THR

The threshold at which the interval ends (it ends if U.thr â&#x2020;&#x2019; 2/3 VCC)

7

DIS

8

V+, VCC

A timing interval can be interrupted by applying a reset pulse to low (0V)

Connected to a capacitor whose discharge time will influence the timing interval The positive supply voltage which must be between 3 and 15 V

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OPERATION OF ULTASONIC SENSOR CIRCUIT INSTALLATION OF TRANSDUCER PAIR

When somebody comes in front of the ultrasonic piezoceramic transducer pair, the status LED (LED1) glows because of the signal reflected from the body of the visitor.

The circuit can be assembled on any general-purpose PCB. The transmitter and the receiver should be aligned such that the transmitted ultrasonic signal is optimally received by the receiver after reflection. Fig. 4 shows installation of the ultrasonic piezoceramic transducer pair operating at around 40 kHz

CONCLUSION Thus detailed explanation of obstacle detection using ULTRASONIC sensor and various components involved in the obstacle detection mechanism are discussed in the above chapter.

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CHAPTER 9 GSM-R FOR LOCATION DETECTION INTRODUCTION This deals with location detection with help of GSM-R technique and various components involved in the location detection mechanism and its features.

GENERAL DESCRIPTION GSM-R TECHNICAL OVERVIEW It is common for Railway companies to deploy and manage their own communication networks to facilitate communications between personnel on board the trains, personnel at train stations, and for personnel working along the railway (e.g. shunting teams). These networks are also used to monitor and report on the positions of the trains at all times, and if necessary, to help manage critical events to keep operations running smoothly. A well-adopted approach for Railway communications is to deploy a GSM network, where signaling protocol stacks are customized so that special needs can be managed. This technology is typically referred to as GSM-Railways (GSM-R). A GSM-R network is designed to provide several applications such as communications for automatic train control, communications to and from the train engineer, communications between shunting teams and emergency communications within an area GSM-R also has the potential to add another revenue source for Railways by allowing passengers to use the network during the journey and at the train stations, much in the same way that airlines do today.

CHALLENGE BEHIND THE IMPLEMENTATION OF GSM-R The most important requirement for GSM-R networks is that they operate at 100% availability and at a very high quality level, as real-time train operations and

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train emergencies must be managed very rapidly. Another complication lies in GSMRs ability to place group calls. This ‘walkie-talkie’ function allows for broadcast communications or group communications, and since the system only permits one person to talk at a time (while the others in the group are forced to listen), call priority must be carefully managed. Finally, a Railway network must provide location service to determine the exact position of personnel with handsets at any time.

GSM-R IN OUR PROJECT The roled played by GSM-R in our project is very crucial.GSM-R are technology is already in use in some of the well developed European countries.But the way they have been implemented in these countries is entirely differ from our project.usually GSM-R technique implemented is not much differ from mobile to mobile communication i.e it is much similar to mobile communication using GSM technology.

The GSR-R also consists of GSM modem which collects data and send this data’s to a control centre which is located near to a staion through a mobile operator tower’s.

In similar way GSM modem are implemented in running train and collects the data’s from the driver and send this to near by control centre.such type of communication is now being followed some European countries.But this type of communication is not suitable for train moving at a speed greater than 350mph.Also implementing such type of communication for each and every train can severly increase the capital cost of the whole railway system. Also coverage of mobile operator’s towers in all areas is not possible(where living habitat of human being is less though railway network is present) The above drawbacks are overcomed in our proposed project.As a startup,the whole communication system is implemented near to a railway crossing.The communication

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system comprises of GSM modem,controller,sensor unit.The reason behind the implementation of whole communication system near Railway crossing is that,the controller and sensor needed for communication is less in numberi.e in many countries automatic gate controlling systems are followed for unmanned railway crossings.The automatic gate controlling systems are implemented with help of controller,sensor and D.C or A.C motor.The same controller,sensor can also be used for the above explained GSM-R based communication system.For this purpose the whole GSM based communication system is implemented near to a railway crossings.

The prime motive of our project is “LOCATION DETECTION USING GSM-R TECHNIQUE” ,in order to benefit a third partyi.e passenger.It is a usual way that the data’s are transferred to control centre and from here it is provided to passenger through displays(LED display) regarding arrival and departure of a particular train.But in many cases it is not happening so i.e the data’s provided to passenger is usually false data only. Because of false timings the passenger are compled to wait for several hours in the railway compartment itself.

The above disadvantage is overcomed in our proposed work.As soon as train movement is sensed by the sensor unit and the controller will send the data’s regarding the particular train through GSM modem as short message(SMS) to the users.In this way a passenger with a cell phone is able to know about a particular train and accordingly the passenger can act with the message i.e whether the passenger can wait for the particular train or otherwise he can opt for other way of transport.

Because of this way of communication it doesnot need any driver intervention to send data’s of a particular train to control centre and then to the passenger through display’s.

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Due to our proposed work ,data’s can be transferred to passenger in a very efficient and simple way.Also implementing a single communication system at a particular location for all train service in that location will greatly reduce the capital cost of railway network.

One more advantage of our proposed work is that,we are able to have GSM based communication system for train speed greater than 350mph.since GSM-R technique implemented in certain european countries is not suitable for train speed grater than 350mph.( it is of great interest that many countries are interested to start train service more than 350mph).

COMPONENTS OF GSM-R BASED COMMUNICATION SYSTEM · GSM MODEM · MICROCONTROLLER · SENSOR · MAX 232(IC) · RS-232(CABLE) (Microcontroller and sensor(IR) are already discussed)

GSM MODEM GENERAL DESCRIPTION FOR GSM MODEM GSM is a GSM cellular modem for serial data rates of up to 115.2K bps.

Compact size and quick installation provides an effcient replacement to serial cable for long distances where cellular service is available. Stand-alone modems provide

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effcient and low cost wireless communication for serial devices, loggers, data acquisition, and control systems. A simple setup includes a GSM modem with cellular account at the remote site/ logger and 56K dial-up phone modem at the base station connected to PC-software. For mobile-mobile applications 56K phone modem can be replaced with GSM modem. GSM modems with cellular service allow for real-time monitoring and control of remote data loggers and irrigation systems by simply dialing into cellular or land phone networks.

GSM modems are programmable using windows standard Hyper-terminal, AT commands. Each GSM modem requires a SIM card, cellular phone number and wireless Circuit-switched data (CSD) service from wireless service provider.

TECHNICAL FEATURES This GSM modem is a highly flexible plug and play quad band gsm modem for direct

and

easy

integration

to

RS

232.supports

voice,Data/Fax,SMS,GPRS and integrated TCP/IP

feartures

stack. This modem has

following technical features.

Quad band GSM/GPRS 850/900/1800/1900 Mhz GPRS multi-slot Class 10/8 GPRS mobile station class B Compliant to GSM phase 2/2+.class 4 (2W@850/900Mhz) class 1(1W@1800/1900Mhz)control via AT Commands (GSM 07.07,07.05 and enhanced AT commands) Operation temperature(-20 degC to+55 degC)

like

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SPECIFICATIONS FOR SMS Point-to-point MO and MT SMS

cell

broadcast Text and

PDU

mode POWER SUPPLY Use AC - DC Power Adaptor with following ratings DC Voltage : 12V DC Current : 1A Polarity : Centre +ve & Outside -ve Current Consumption in normal operation 250mA, can rise up to 1Amp while transmission.

INTERFACES RS-232 through D-TYPE 9 pin connector, Serial port baud rate adjustable 1200 to115200 bps (9600 default) Stereo connector for MIC & SPK Power supply through DC socket SMA antenna connector Push switch type SIM holder LED status of GSM / GPRS module

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MAX232, MULTICHANNEL RS-232 DRIVERS/RECEIVERS 9.1 GENERAL DESCRIPTION The MAX232 is an integrated circuit that converts signals from an RS-232 serial port to signals suitable for use in TTL compatible digital logic circuits.The MAX232 is a dual driver/receiver and typically converts the RX,TX,CTS and RTS signals.The MAX220MAX249 family of line drivers/receivers is intended for all EIA/TIA-232E and V.28/V.24 communications interfaces, particularly applications where +12V and

-12V is not

available.

These parts are especially useful in battery-powered systems, since their low-power shutdown

mode

reduces

power

dissipation

to

less

than

5microwatt.The

AX225,MAX233,MAX235 and MAX245/Max246/MAX247 use no external components and are recommended for applications where printed circuit board space is critical.

9.2 FEATURES ·

Operate from single +5V power supply (+5V and +12V –MAX231/MAX239)

·

Low-power receive mode in shutdown(MAX223/MAX242)

·

Meet all EIA/TIA-232E and V.28 specifications

·

Multiple Drivers and Receivers

·

3-State Driver and Receiver Outputs

·

Open-Line Detection(MAX243)

9.3 APPLICATIONS ·

Portable Computers

·

Low-Power Modems

·

Interface Translation

·

Battery-Powered RS-232 Systems

·

Multidrop RS-232 Networks

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9.4 CIRCUIT DIAGRAM FIG 9.4 MAX232 CIRCUIT DIAGRAM

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GENERAL DESCRIPTION In telecommunications, RS-232 (Recommended Standard 232) is a standard for serial binary data signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports.

FIG 9.5(A) RS232 DB9 PINOUT

The RS232 connector was originally developed to use 25 pins. In this DB25 connector pinout provisions were made for a secondary serial RS232 communication channel. In practice, only one serial communication channel with accompanying handshaking is present. Only very few computers have been manufactured where both serial RS232 channels are implemented. Examples of this are the Sun SparcStation 10 and 20 models and the Dec Alpha Multia.

Also on a number of Telebit modem models the secondary channel is present. It can be used to query the modem status while the modem is on-line and busy communicating.

On personal computers, the smaller DB9 version is more commonly used today. The diagrams show the signals common to both connector types in black. The defined pins only present on the larger connector are shown in red. Note, that the protective ground is assigned to a pin at the large connector where the connector outside is used for that purpose with the DB9 connector version.

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The pinout is also shown for the DEC modified modular jack. This type of connector has been used on systems built by Digital Equipment Corporation; in the early days one of the leaders in the mainframe world. Although this serial interface is differential (the receive and transmit have their own floating ground level which is not the case with regular RS232) it is possible to connect RS232 compatible devices with this interface because the voltage levels of the bit streams are in the same range. Where the definition of RS232 focussed on the connection of DTE, data terminal equipment (computers, printers, etc.) with DCE, data communication equipment (modems), MMJ was primarily defined for the connection of two DTE's directly.

FIG 9.5(B) RS232 SERIAL CONNECTOR

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OPERATION As soon as the movement of train is detected by the sensor unit,an interrupt signal will be given from the sensor unit to the Microcontroller.The Microcontroller will transmit the data’s accordingly to the GSM modem.Before transmitting data to GSM modem,the output Microcontroller are in the form of TTL logic and this need to be converted into RS-232 and this is achieved with suitable converter(MAX 232). For transmitting data’s from converter to GSM modem an RS 232 cable is used.From GSM modem the data’s are transferred in the form of short message service(SMS) to the user(passenger) or it is transferred to control centre and from there it is transferred to displays and users.

CONCLUSION Thus detailed explanation of location detection using GSM-r technique and various components associated with location detection are discussed in the above chapter.

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CHAPTER 10 KEIL SOFTWARE DESCRIPTION INTRODUCTION TO KEIL Keil software provides the premier 8051 development tools to industry .The keil software comprises of different tool kits. A tool kit consist of several application program that we can use to create our 8051 application .When we use keil software for our project the development cycle is some what similar to a software development project .It consist of creating source file in C or assembly language compiling or assembling the source files debugging error in the source file, linking file from complier and assembler and finally building a project linking all the files and testing the linked application.

FUNCTIONING OF KEIL All the files are created through the micro vision integrated development environment are then passed to the C51 compiler or A51 assembler. The compiler and assembler process source files and create relocatable object files. Object files created by the compiler or assembler may be used by the library manager to create a library. A library is a specially formatted, ordered program collection of object modules that linker can process. When the linker processes a library, only the object modules in the library necessary for program creation are used. Object files created by the compiler and assembler and library files created by the library manager are processed by the linker to create an absolute object module. An absolute object file or module is an object file with no relocatable code. All the code in an absolute object file resides at fixed locations.

The absolute object file created by the linker may be used to program EPROM or other memory devices. The absolute object module may also be used with the dScope51 debugger / simulator or with an in-circuit emulator. The dScope-51 source level debugger/simulator is ideally suited for fast, reliable high-level-language program debugging. The debugger contains a high-speed simulator and a target debugger that let you simulate an entire 8051 system including on-chip peripherals. By loading specific I/O drivers, we can simulate the attributes and peripherals of a variety of 8051 family.

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The RTX-51 real time operating system is a multitasking kernel for the 8051 family. The RTX-51 real time kernel simplifies the system design, programming, and debugging of complex applications where fast reaction to time critical events is essential. The kernel is fully integrated into the C51compiler and is easy to use. Task description tables and operating system consistency are automatically controlled by the BL51 code banking linker/locater.

µVISION2 INTEGRATED DEVELOPMENT ENVIRONMENT The µVision2 IDE is a Windows-based software development platform that combines a robust editor, project manager, and makes facility. µVision2 supports all of the KEIL tools for the 8051 including the C compiler, macro assembler, linker/locator, and objectHEX converter. µVision2 helps expedite the development process of your embedded applications by providing the following: ·

Full-featured source code editor,

·

Device database for configuring the development tool setting,

·

Project manager for creating and maintaining your projects,

·

Integrated make facility for assembling, compiling, and linking your embedded applications,

·

Dialogs for all development tool settings,

·

True integrated source-level Debugger with high-speed CPU and peripheral simulator,

·

Advanced GDI interface for software debugging in the target hardware and for connection to Monitor-51

·

Links to development tools manuals, device datasheets, & user’s guides.

The µVision2 IDE combines project management, a rich-featured editor with interactive error correction, option setup, make facility, and on-line help. Use µVision2 to create your source files and organize them into a project that defines your target application.

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ÂľVision2 automatically compiles, assembles, and links your embedded application and provides a single focal point for your development efforts.

SOFTWARE DEVELOPMENT CYCLE When you use the Keil Software tools, the project development cycle is roughly the same as it is for any other software development project.

1. Create a project, select the target chip from the device database, and configure the tool settings.

2. Create source files in C or assembly.

3. Build your application with the project manager.

4. Correct errors in source files.

5. Test the linked application.

A block diagram of the complete 8051 tool set may best illustrate the development cycle. Each component is described below.

FIGURE: 2.4 SOFTWARE DEVELOPMENT CYCLE

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C51 Compiler & A51 Assembler Source files are created by the µVision2 IDE and are passed to the C51 Compiler or A51 assembler. The compiler and assembler process source files and create relocatable object files.

The Keil C51 Compiler is a full ANSI implementation of the C programming language that supports all standard features of the C language. In addition, numerous features for direct support of the 8051 architecture have been added.

The Keil A51 macro assembler supports the complete instruction set of the 8051 and all derivatives.

C51 Optimizing C Cross Compiler The Keil C51 Cross Compiler is an ANSI C Compiler that was written specifically to generate fast, compact code for the 8051 microcontroller family. The C51 Compiler generates object code that matches the efficiency and speed of assembly programming.

Using a high-level language like C has many advantages over assembly language programming: ·

Knowledge of the processor instruction set is not required. Rudimentary knowledge of t he memory structure of the 8051 CPU is desirable (but not necessary).

·

Details like register allocation and addressing of the various memory types and data types is managed by the compiler.

·

Programs get a formal structure (which is imposed by the C programming language) and can be divided into separate functions. This contributes to source code reusability as well as better overall application structure.

·

The ability to combine variable selection with specific operations improves program readability.

·

Keywords and operational functions that more nearly resemble the human thought process may be used.

·

Programming and program test time is drastically reduced.

·

The C run-time library contains many standard routines such as: formatted output, numeric conversions, and floating-point arithmetic. _ Existing program

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parts can be more easily included into new programs because of modular program construction techniques.

·

The language C is a very portable language (based on the ANSI standard) that enjoys wide popular support and is easily obtained for most systems. Existing program investments can be quickly adapted to other processors as needed.

2.4.3 LIB51 Library Manager The LIB51 library manager allows you to create object library from the object files created by the compiler and assembler. Libraries are specially formatted, ordered program collections of object modules that may be used by the linker at a later time.

When the linker processes a library, only those object modules in the library that are necessary to create the program are used.

2.4.4 BL51 Linker/Locator The BL51 linker creates an absolute object module using the object modules extracted from libraries and those created by the compiler and assembler. An absolute object file or module contains no re-locatable code or data. All code and data reside at fixed memory locations. The absolute object file may be used: ·

To program an EPROM or other memory devices,

·

With the µVision2 Debugger for simulation and target debugging,

·

With an in-circuit emulator for the program testing.

µVision2 Debugger The µVision2 symbolic, source-level debugger is ideally suited for fast, reliable program debugging. The debugger includes a high-speed simulator that let you simulate an entire 8051 system including on-chip peripherals and external hardware. The attributes of the chip you use are automatically configured when you select the device from the

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Device Database. The µVision2 Debugger provides several ways for you to test your programs on real target hardware. ·

Install the MON51 Target Monitor on your target system and download your program using the Monitor-51 interface built-in to the µVision2 Debugger.

·

Use the Advanced GDI interface to attach use the µVision2 Debugger front end with your target system.

Monitor-51 The µVision2 Debugger supports target debugging using Monitor-51. The monitor program resides in the memory of your target hardware and communicates with the µVision2 Debugger using the serial port of the 8051 and a COM port of your PC. With Monitor-51, µVision2 lets you perform source-level, symbolic debugging on your target hardware.

LIMITATIONS OF KEIL 2.4 The Cx51 compiler embodies some known limitations that are listed below. ·

A maximum of 19 levels of indirection (access modifiers) to any standard data type are supported. This includes array descriptors, indirection operators, and function descriptors.

·

Names may be up to 256 characters long. The C language provides for case sensitivity in regard to function and variable names.

·

The maximum number of case statements in a switch block is not fixed. Limits are imposed only by the available memory size and the maximum size of individual functions.

·

The maximum number of nested function calls in an invocation parameter list is 10.

·

The maximum number of nested include files is 9. This value is independent of list files, preprocessor files, or whether or not an object file is to be generated.

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·

The maximum depth of directives for conditional compilation is 20. This is preprocessor limitation.Instruction blocks ({…}) may be nested up to 15 levels deep.

KEIL PROGRAM #include<stdio.h> #include<string.h> #include<reg51.h> #include<serial.h> sbit EN = P1^4; sbit IN1 = P1^3; sbit IN2 = P1^2; code unsigned char SMS1[2] = "AT" ; code unsigned char SMS2[9] = "AT+CMGF=1" ; code unsigned char SMS3[8]= "AT+CMGS=" ; // send " code unsigned char SMS4[10]= "9894576452" ; // send " code unsigned char SMS5[94] = "WELCOME TO INDIAN RAILWAYS : TRAIN CROSSED EGMORE STATION DATE : 10/03/2009 TIME : 10:30 A.M" ; //code unsigned char SMS6[5] = "hello"; sbit BUZZER = P0^7; unsigned int j; void sendSMS(); void delay1(unsigned char Deltime); unsigned char count; void clockwise(); void anticlockwise(); void main() { EA = 1; EX0 = 1; IT0 = 0; EX1 = 1; IT1 = 1; BUZZER =1; initserial();

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while(1) { } } void EXTINT0() interrupt 0 { EA=0; clockwise(); sendSMS(); EN=0; for(j=0;j<=60000;j++); for(j=0;j<=60000;j++); anticlockwise(); for(j=0;j<=60000;j++); for(j=0;j<=60000;j++); for(j=0;j<=60000;j++); EN=0; EA=1; } void EXTINT1() interrupt 2 { BUZZER = 0; for(j=0;j<=30000;j++); for(j=0;j<=30000;j++); for(j=0;j<=30000;j++); BUZZER = 1; } void sendSMS() { unsigned char i; for (i=0;i<2;i++) sendserial(SMS1[i]); sendserial(0X0D); delay1(60);

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for (i=0;i<9;i++) sendserial(SMS2[i]); sendserial(0X0D); delay1(60); for (i=0;i<8;i++) sendserial(SMS3[i]); sendserial(0x22); // " for (i=0;i<10;i++) sendserial(SMS4[i]); sendserial(0x22); // " sendserial(0X0D); delay1(60); for (i=0;i<94;i++) sendserial(SMS5[i]); sendserial(0X1A); delay1(80); } void delay1(unsigned char Deltime) { unsigned char i ; for (i=0;i<Deltime;i++) // 50ms delay - for 2 sec loop 40 times, 4 sec loop 80 times { TH0 = 0X4B; TL0 = 0XFD; TF0 = 0; TR0 = 1; while(TF0==0); } } void anticlockwise() { EN=1; IN1=0; IN2=1; } void clockwise() { EN=1;

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IN1=1; IN2=0; }

PROGRAM FOR OBSTACLE DETECTION USING ULTRASONIC SENSOR void sendserial(unsigned char); //void serial_string(unsigned char *str); void initserial(); void initserial() { TMOD=0X21; SCON=0X50; TH1=0XFD; TL1=0XFD; TR1=1; } void sendserial(unsigned char mydata) { TI=0; SBUF= mydata; while(TI==0); }

CONCLUSION

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Thus detailed explanation of KEIL software development and programming in KEIL software was discussed in the above chapter.

CHAPTER 12 CONCLUSION

GSM-R

technology in our project makes easy and efficient

data transfer to the

passengers and peoples at the railway station. Therefore our project reduces passengers time and to catch the train at exact time through SMS. This is one of the major advantages of choosing our project. Automatic gate control and Obstacle detection across the track can prevent accidents in railway network. This is also another advantages of choosing our project.

From the above discussion and information of this system we, upto now surely comes to know that it is highly reliable effective and economical at dense traffic area, suburban area and the route where frequency of trains is more.

As it saves some auxiliary structure as well as the expenditure on attendant it is more economical at above mentioned places than traditional railway crossing gate system. We know that though it is very beneficial but it is also impossible to install such system at each and every places, but it gives certainly a considerable benefit to us, thereby to our nation.

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CHAPTER 13 REFERENCES

1. S.L.HO, K.K.Lee, K.Y.Lee, H.Y.Tam, W.H.Chung , S.Y.Liu , C.M.Yip , T.K.Ho “ A

Comprehensive Condition Monitoring of Modern Railways”

IEEE transactions on 2. Liao min, Zhang Zhangdui,”Location Dependent Addressing Using GSM-R Cellular Positioning “ IEEE conference on mobile communication,2000.

3. Emad Aboelela, William Edberg, Christos Papakonstantinou and Vinod Vokkarane “Wireless Sensor Network Based Model for Secure Railway Operations” IEEE conference on wireless system,2006.

4. Juan Jestis Garcia, Jestis Urena, Manuel Mazo, Cristina Losada, Alvaro Hernandez, Carlos De Marziani ’’Data Integration by considering spatial diversity in an IR barrier ‘’ IEEE transactions on ,2006.

5. H.Hofestadt “GSM-R: Global System for Mobile Radio Communications for Railways” IEEE transactions on

,1995.

6. Margarita Georgieva, Ivan Nenov “Implementation of Microcontrollers in Railway Automatic Traffic Control Systems” IEEE transactions on

,2005.

7. Kazutoshi SATO, Hideki ARAI, Toshiyuki SHIMIZU, Masahiro TAKADA “Obstruction Detector Using Ultrasonic Sensors for Upgrading the Safety of a Level Crossing” IEEE transactions on 1998.

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