CONTENTS

Abstract Introduction Steps of project making Block diagramCircuit diagramWorkingFrame formatFlow chartHardware section

Pcb manufacturing process and pcb layout Components used Components description Microcontroller programming(ASM)

Software section Introduction to visual basic Mscomm control Visual basic window Software coding

PrecautionsApplicationsSoftwares usedReferencesDatasheets of ICs

Abstract:-

Now-a-days every institution needs automation. As a part of college automation, we have decided to do a project “Voice Interactive System for College Automation”.

IVRS is a complete College Automation System which takes in to account the three important dimensions of Educational system namely students, teachers and parents. This system becomes handy in order that the parents get complete information about their wards, in terms of daily attendance, weekly attendance, monthly attendance, performance in class tests, unit tests, model examinations and also the semester examination.

The main motto of this system to give the information of student learning in college such as accounts, marks, attendance.

Every student is assigned a unique pin number, which is disclosed, only to the parents. The parents can use their mobile or regular telephone and using the pin numbers they can get the complete information about their wards.

IVR System:-

Introduction:-

Interactive voice response, or IVR, is a technology that allows a computer to detect keypad inputs. IVR technology is used extensively in telecommunications.

IVR systems are typically used to service high call volumes, reduce cost and improve the customer experience. Examples of typical IVR applications are: telephone banking, televoting, and credit card transactions.

Call centers use IVR systems to identify and segment callers. The ability to identify customers allows the ability to tailor services according to the customer profile. It also allows the option of choosing automated services. Information can be fed to the caller allowing choices such as: wait in the queue, choose an automated service, or request a callback.

More advanced IVR systems include speech-recognition software that allows a caller to communicate with a computer using simple voice commands. Speech recognition software has become sophisticated enough to understand names and

long strings of numbers -- perhaps a credit card or flight

number.

Working model

The whole system is design around two parts

1. First is Hardware section.2. Second is software section.

1. First is Hardware section:-In a hardware section is also more section which is

a>.DTMF. Decoder

b>. Microcontroller

c>. comparator

DTMF. Decoder: -

Its function is to decode the up coming hardware tones from the telephone line in a binary format. To decode this tone we use a DTMF. Tone decoder which is 8870. This is inbuilt IC for decoding the tones.

Microcontroller:-

this is a medium between decoder and a pc to communicate. In this software first we when the ring is coming from the circuit is given by comparator pulses .its asm software count the ring when the ring is greater than 4 its energized the relay to pick up the phone. When phone is pick up It gives command to the pc which is shown in frame the communication is established. if user input the no then microcontroller continues scan the dtmf ic if it found any code the transfer to the pc.

In this system we are using Microchip Company’s controller of series 16f876A. Which is RISC base processor .Has inbuilt USART. It is programmed in assembly language and its instruction set is totally different from 8051. By the help of MPLAB software provide by company of controller

Led indication is used to see the dtmf outputs and the ring signal.

Comparator:- comparator is used to detect the ring signal . when the ring is coming comparator circuit gives output is high otherwise low which is pick from dtmf ic.

Major Component of system.

1. Lcd. Display: - It has 16x2 LCD display to see the status of the transmitter.Power supply:-The system instead of relay is operated in 5v.which is providing by

the positive regulator 7805.

But relay has unregulated power supply about 12-15v.

Max232:-This is providing in the system is to convert the level of 0 to 5 to -12 to +12v. But

practically its work in between (-8.5 to +8.5).a. Full wave rectifier: - The full wave Bridge rectifier is used to convert 12 ac

to the pulsating dc which is equal to average value.Filter is a used to convert pulsating dc to constant dc. It may me capacitor, RC

network, a. 12 v step down transformer (500m amp)

b. Full wave rectifier.c. Filter.d. linear regulator.b. 12 v step down transformer(500m amp):- Step down transformer is used

to convert 230v ac to 12v ac. With current rating of 500 mump.inductance. depends upon the current following in the circuit or impedance of

circuit. But in this system we use capacitor.d.Linear regulator:- regulator are used the system is used to convert high

voltage to +5v constant dc.

Second is software section:- In this section software is build around the visual basic. When it received command from the system its gives the response in a voice for from the sound port which is fed to the speaker of phone. if no any command received in 25 second it sends a command to

disconnect the phone.

Steps of project making

The following steps have been followed in carrying out the project

1) Understand the working of the circuit.

2) Prepare the circuit diagram.

3) Prepare the list to components along with their specification estimate the cost

4) and procure them after carrying out market survey.

5) Plan and prepare PCB for mounting all the components.

6) Fix the components on the solder them.

7) Test the circuit for the desired performance.

8) Trace and rectify faults if any.

9) Give good finish to the unit.

10) Prepare the project report.

BLOCK DIAGRAM:-

CIRCUIT DIAGRAM

WORKING:-

When the incoming call comes, the First pin of DTMF8870 senses the incoming call, voltage of second no. pin of 8870 will change from 2.5V to 1V.

The comparator senses the change in voltage of second no. pin and its output goes up, this out put is connected to the microcontroller which senses this change in comparator state and gives an instruction to relay to switch on the telephone hook switch.

Simultaneously the microcontroller gives an instruction to the PC to play the welcome message.

Now caller is asked to press the specific keys as per the menu options.

Now user dials student pin no.which is sensed by DTMF 8870 and converted into equivalent binary no. now these binary values sensed by MAX 232 through microcontroller and converted to RS232 format which is compatible with our pc. Now pc is able to understand these logics via RS232 connectorAs per the key pressed the software decides what action should be taken. And the corresponding student details will be delivered.As for example when the incoming calls comes the ring is

detected by the hardware circuit and a welcome message “WELCOME TO ORIENTAL INSTITUTE OF SCIENCE & TECHNOLOGY” is played.

Then it asks to enter the single digit roll no., after dialing the roll no. again a message “PRESS 1 FOR ATTENDANCE DETAILS, PRESS 2 FOR MARKS DETAILS, PRESS 3 FOR ACCOUNTS DETAILS AND PRESS 9 FOR EXIT” is played.

As per the key pressed corresponding data is fetched from the database and the message is played.

FRAME FORMAT:-

FLOW CHART:-

PCB MANUFACTURING PROCESS :

PCB LAYOUT

Lay out of the desired circuit is the most important in any circuit board manufacturing process. The following points are to be observed while performing the layout of the PCB

Sufficient space should be maintained between two components. High heat dissipation components like high voltage resistors should be mounted at a sufficient distance from the semiconductors and electrolytic capacitors. Components layout should make proper combination with copper side circuit layout. Circuit copper line thickness should be decided taking into account the current drain in the circuit.

PREPARATION OF SCREEN:

Nylon bolting cloth (Silk screen cloth) is stretched and attached to a wooden frame. Photosensitive chemical (silcot-6) and ammonium bicarbonate is spread on cloth and dried in total darkness. The screen is exposed to UV light and is developed in water.

PRINTING:

The screen is placed on suitable copper laminated sheet on copper side and circuit black printing ink (acid resistant paint) is spread on it. After printing the PCB should be allowed to dry for at least 10 hrs. in a dust proof chamber.

ETCHING:

The removal of excess copper on the copper laminated PCB apart from the printed circuit is known as etching. Generally PCB is placed in F3C13 solution and kept for one hour.

DRILLING:

Under this operation drilling should be done as per circuit lay with the suitable drill and high speed machine. Drilling should always be done from copper side to avoid possibility of coming out of copper circuit and chipping out of Bakelite.

GREEN MAKING:

It is done with special epoxy paint and special thinner is requited for cleaning the screen. It provides as better and also prevents frequency overlapping between the tacks at high frequency operation.

THINNING:

It is an electroplating process (tin plating) done to increases the conductivity of the conducting medium and to avoid oxidizing effect.

COMPONENT MOUNTING:

All components are mounted at their respective position as per the components layout. Proper precautions should be taken during mounting process.

ETCHING PROCESS:

Etching process requires the use of chemicals acid resistant dishes and running water supply Ferric chloride is maximum used solution but other enchants such as ammonium per sulfate can be used. Nitric acid can be used but in general it is not used due to poisonous fumes. The pattern prepared is glued to the copper surface of the board using a latex type of adhesive that can be cubed after use. The pattern is laid firmly on the copper use a very sharp knife to cut round the pattern carefully a remove the paper corresponding to the required copper pattern areas. Then apply the resist solutions, which can be kind of ink proportion fort the purpose maintaining smoothing clean outlines as far as possible. While the board is drying test all the components.

Before going to next stage, check the whole gotten and cross cheek against the circuit diagram check for any freeing matte on the copper. The etching bath should be in a galls or enamels disc. If using crystal of ferric-chloride these should be thoroughly dissolved in water to the proportional suggested. There should be 0.5 Lt. Of water for 125 Gm. of crystal.

Water liquid should be thoroughly deflated and druid in water land; never pour down the drain. To prevent particles of copper hindering further etching, agitate the solutions carefully be gently twisting or rocking the tray.

The board should not be left in the bath a moment longer than is needed to remove just the right amount of copper. In spite of there being a resist coating there is no protection against etching away through exposed copper edges; this leads to over etching. Have running water ready so that etched board can be removed properly and rinsed; this will hall etching immediately.

Drilling is one of those operations that call for great care because most of the holes will be made a very small drill. For most purposes a 1 mm drill is used Drill all holes with this size first those that need to be larger can be easily drilled again with the appropriate lager size.

COMPONENT ASSEMBLES:

From the greatest variety of electronic components available today, which runs into tent of thousands of different types it is often a perplexing task to know which the right task for a given job is. There should be damage such as hair line crack intuit opera on PCB that could age a seriousfiec on the operational ability to the completed assemble. If there are than they can and should be repaired fiesta bye soldering a short link of bare copper wire over the affected part.

The most popular method of holding all the items is to been the wires future apart after they even been indebted in the appropriate holes. This will hold the component in position ready for soldering.

Some components will be considerably larger than other occupying and possible partially obscuring neighboring components. Because of this best to start by mounting the smallest first and progressing through to the largest. Before starting make certain that no further drilling I likely to be necessary because access may be impossible later.

Next will probably be the resistor small signal diodes of other similar size components some capacitor are very small but it would be best to fit these after words when fitting each group of components marks of each one on the components its as it is fitted and if we have to leave the job we know where to recommence. Although transistor & integrated circuit are small items there are good reasons for leaving the soldering of these until the last step the main pint is that these components are sensitive to heart and is subjected to prolonged application to the soldering iron they could be internally damaged.

All the components before mounting are rubbed with sandpaper so that oxide layer is removed from their tips. Now they are mounted according to the components layout.

SOLDERING TECHNIQUES:

A soldered connection ensures metal continuity. The soldering process involves: Melting of the flux which in turn removes the oxide films on the metal to be soldered. Melting the solder which removes the impurities. The solder partially dissolve of the metal in the connection. The solder cools and fuses wit the metal.

The soldering techniques involves knowledge of :

Soldering iron

Soldering wire

Soldering procedure

Replacing components

Prosecutions of when using C-MOS, devices

Knowledge of good and bad soldering joints.

SOLDERING & SOLDERING TECHNIQUES

Soldering Iron :

Soldering iron is an essential tool for soldering. A. Soldering iron should give sufficient heat a melt solder by heat transfer when the iron tip is applied to a connection to be soldered.The selection of the soldering iron can be made as regard to its tips size shape and wattage. Soldering iron temperature is selected and controlled according to the work to be performed. Generally two types of soldering irons are available: Soldering Pencil and Soldering Gun.

Soldering Pencils :

These are light weight soldering iron which can generate around 12 watts to 50 watts of heat. Modular soldering

(2) SOLDERING ALLOY

Soldering Materials :

The soldering material is used to join together two or more metals at temperatures below their melting point. The solder alloy consists of Lead (37%) and Tin (63%). The continuous connection between two metal joint is made by solder materials.

Most commonly used solder wire consists of 60% of Tin 40% Lead. This is in the from of a hollow wire whose center is filled with an organic paste like material called rosin. Its melting temperature is 190 degree centigrade.

FLUX :

Flux is a material used to aid soldering process. Flux is needed to scratch away the small film of oxide on the surface of metals to be soldered. This flux forms a protective film that prevents reoxiadation while the connection is heated to the point at which the solder melts. Flux is very helpful on old dusty, eroded joint.

SOLDERING PROCEDURE

The soldering procedure involves selection of soldering iron cleaning of components to be soldered and cleaning of the PCB to be soldered. The soldering iron should be selected according to the job and should be powerful enough to provide heat. The tip of the soldering iron should be selected as per the space available for soldering. The component that has to be soldered should be properly bent and its leads should properly inserted in the PCB. Before. If one has already identified the fault component, then one should not try to remove or desolder the component. The components should simply be cut and taken out.

PRECAUTIONS WHEN USING C-MOS DEVICES:

CMOS Devices are sensitive to static charges. So care has to be taken while handling this device. Static charge is generated by rubbing cloth with human body or by any other friction of human body. Before string or handling CMOS Devices touching the ground or metallic chassis of the equipment. One can wear a metallic band in hand which is connected to ground. The working table should be either of wood or should have rubber sheet. The soldering iron tip should be static charge free.

DESOLDERING TECHNIQUES

By using a disordering wick

By using a disordering pump

Disordering wick is made of fine copper wire mesh. When this is applied to the heated components, the molten solder gets attached to the wire mesh by capillary action. Disordering pump has a suction pump. The nozzle of the disordering pump is kept to the heated component. The molten solder is sucked by a spring action. Insertion in the PCB, the lead should be properly cleaned. After component has been inserted it can be soldered. The oxide on the PCB can be removed by using flux, sandpaper. The tip of the soldering iron should be clean and should have proper shape. The shape of the tip normally gets bad over a period of time. The shape can be made proper by filling. During soldering excessive heat is generated at the soldering iron tip. If the soldering iron tip is in contact with component for a longer time then there is possibility of damaged or may loose its characteristics. Place iron tip at 45 degree to the PCB and component joint. Place the solder near the iron and let it flow. Smoothen the area of joint by the soldering iron tip. By doing this, the molten solder alloy flows into the PCB hole. Soldering should be done when the equipment is off.

REPLACEMENT OF COMPONENT

In case of single sided PCB, the component to be removed can be disordered with the help of iron and flux. The only precaution that has to be taken is that track should not break while removing. In case of Through Hole PCB, care has the to be taken so that component while removing does not damaged the Through Hole. In this case the component is soldered on one side and the lead flows through the hole to the other sides, so disordering and removing becomes very difficult and required practice.

DIODES :-

It is s two terminal device consisting of a P-N junction formed either in GE or SI crystal. The P and N type regions are referred to as anode and cathode respectively.Commercially available diodes usually have some means to indicate which lead is P and which lead is N. Standard notations consists the number proceeded by IN such as In 240& 250. Here 240 and 250 correspond to color band.

COMPONENTS

Number Quantity

IC’s Pic16f876a 1 LM7805 1 MT8870 1 MAX232 1

Transistor BC547B 2

Light Emitting Diodes (LED’s) Red 7

Diodes 1N4007 6

Crystal 16MHz 2

Capacitors 1000mF/25V 4 100mF/25V 3

Resistors Preset 10k 1 10k 4 4.7k(Resistor network) 4 1k 4

Transformers 0-12v 500mA 1

PCB 4” X 6” 1

Display LCD(16*2) 1

Relay Relay(12) 2

Miscellaneous IC Base (40pin) 28 Ferric Chloride 100gms. Soldering Wire 20gms. Soldering Paste 10gms. Connecting wires 2metres Main cable

COMPONENT DESCRIPTION

Microchip PIC16F876A Microcontroller

Description

8-Bit Microcontroller IC Controller Family/Series:PIC16F Memory Size, Flash:14336Byte Memory Size, EEPROM:256Byte No. of I/O Pins:22 No. of PWM Channels:5 Clock Speed:20MHz Interface:I2C, SPI, USART Package/Case:28-SOIC RoHS Compliant: Yes

This powerful (200 nanosecond instruction execution) yet easy-to-program (only 35 single word instructions) CMOS FLASH-based 8-bit microcontroller packs Microchip's powerful PIC® architecture into an 28-pin package and is upwards compatible with the PIC16C5X, PIC12CXXX and PIC16C7X devices. The PIC16F876A features 256 bytes of EEPROM data memory, self programming, an ICD, 2 Comparators, 5 channels of 10-bit Analog-to-Digital (A/D) converter, 2 capture/compare/PWM functions, the synchronous serial port can be configured as either 3-wire Serial Peripheral Interface (SPI™) or the 2-wire Inter-Integrated Circuit (I²C™) bus and a Universal Asynchronous Receiver Transmitter (USART). All of these features make it ideal for more advanced level A/D applications in automotive, industrial, appliances and consumer applications.

Fixed-Voltage Regulator 7805-7812

A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. It may use an electromechanical mechanism, or passive or active electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.

With the exception of shunt regulators, all modern electronic voltage regulators operate by comparing the actual output voltage to some internal fixed reference voltage. Any difference is amplified and used to control the regulation element. This forms a negative feedback servo control loop. If the output voltage is too low, the regulation element is commanded to produce a higher voltage. For some regulators if the output voltage is too high, the regulation element is commanded to produce a lower voltage; however, many just stop sourcing current and depend on the current draw of whatever it is driving to pull the voltage back down. In this way, the output voltage is held roughly

constant. The control loop must be carefully designed to produce the desired trade-off between stability and speed of response.

features :

Output current in excess of 1A

Internal thermal overload protection

No external components required

Output transistor safe area protection

Internal short circuit current limit

Available in the aluminium TO-3 package

Introduction to Visual Basic

What is Visual Basic?

The "Visual" part refers to the method used to create the graphical

user interface (GUI). Rather than writing numerous lines of code to

describe the appearance and location of interface elements, you simply

add prebuilt objects into place on screen. If you've ever used a drawing

program such as Paint, you already have most of the skills necessary to

create an effective user interface.

The "Basic" part refers to the BASIC (Beginners All-Purpose

Symbolic Instruction Code) language, a language used by more

programmers than any other language in the history of computing. Visual

Basic has evolved from the original BASIC language and now contains

several hundred statements, functions, and keywords, many of which

relate directly to the Windows GUI. Beginners can create useful

applications by learning just a few of the keywords, yet the power of the

language allows professionals to accomplish anything that can be

accomplished using any other Windows programming language.

The Visual Basic programming language is not unique to Visual

Basic. The Visual Basic programming system, Applications Edition

included in Microsoft Excel, Microsoft Access, and many other Windows

applications uses the same language. The Visual Basic Scripting Edition

(VBScript) is a widely used scripting language and a subset of the Visual

Basic language. The investment you make in learning Visual Basic will

carry over to these other areas.

Whether your goal is to create a small utility for yourself or your work

group, a large enterprise-wide system, or even distributed applications

spanning the globe via the Internet, Visual Basic has the tools you need.

Data access features allow you to create databases, front-end

applications, and scalable server-side components for most popular

database formats, including Microsoft SQL Server and other enterprise-

level databases.

ActiveX™ technologies allow you to use the functionality provided by other

applications, such as Microsoft Word word processor, Microsoft Excel

spreadsheet, and other Windows applications. You can even automate

applications and objects created using the Professional or Enterprise

editions of Visual Basic.

Internet capabilities make it easy to provide access to documents and

applications across the Internet or intranet from within your application, or

to create Internet server applications.

The MSComm control provides serial communications for your application

by allowing the transmission and reception of data through a serial port.

Basics of Serial Communications:

Every computer comes with one or more serial ports. They are named

successively: COM1, COM2, and so on. On a standard PC, the mouse is

usually connected to the COM1 port. A modem may be connected to

COM2, a scanner to COM3, etc. Serial ports provide a channel for the

transmission of data from these external serial devices.

The essential function of the serial port is to act as an interpreter between

the CPU and the serial device. As data is sent through the serial port from

the CPU, Byte values are converted to serial bits. When data is received,

serial bits are converted to Byte values.

A further layer of interpretation is needed to complete the transmission of

data. On the operating system side, Windows uses a communications

driver, Comm.drv, to send and receive data using standard Windows API

functions. The serial device manufacturer provides a driver that connects

its hardware to Windows. When we use the Communications control, we

are issuing API functions, which are then interpreted by Comm.drv and

passed to the device driver.

As a programmer, we need only concern werself with the Windows side of

this interaction. As a Visual Basic programmer, we need only concern

werself with the interface that the Communications control provides to API

functions of the Windows communications driver. In other words, we set

and monitor properties and events of the Communications control.

MSComm Control:-

The MSComm control provides serial communications for our application

by allowing the transmission and reception of data through a serial port.

The MSComm control provides the following two ways for handling

communications:

Event-driven communications is a very powerful method for handling serial

port interactions. In many situations we want to be notified the moment an

event takes place, such as when a character arrives or a change occurs in

the Carrier Detect (CD) or Request To Send (RTS) lines. In such cases,

use the MSComm control's OnComm event to trap and handle these

communications events. The OnComm event also detects and handles

communications errors.

We can also poll for events and errors by checking the value of the CommEvent property

after each critical function of wer program. This may be preferable if wer application is

small and self-contained. For example, if we are writing a simple phone dialer, it may not

make sense to generate an event after receiving every character, because the only

characters we plan to receive are the OK response from the modem.

Each MSComm control we use corresponds to one serial port. If we need

to access more than one serial port in wer application, we must use more

than one MSComm control. The port address and interrupt address can

be changed from the Windows Control Panel.

Properties Description

CommPort

Sets and returns the communications port number.

Settings Sets and returns the baud rate, parity, data bits, and stop bits as a string.

PortOpen Sets and returns the state of a communications port. Also opens and closes a port.

Input Returns and removes characters from the receive buffer.

Output Writes a string of characters to the transmit buffer.

Establishing the Serial Connection:

The first step in using the Communications control is establishing the connection to the serial port. The following table lists the properties that are used to establish the serial connection:

Although the MSComm control has many important properties, there are a few that we should be familiar with first.

precautions

1) Frist check all component as per the circuit.

2) Check transistor.

3) Pay proper attention to the polarity of capacitors and diodes while assembling.

4) While mounting transistor be sure that you have connected collector, emitter and base properly.

5) Clean PCB after soldering so those components do not short.

6) Remember the anode and cathode of diode before fitting.

7) Remember to check dry soldering and short circuit.

8) IC should be mounted on IC base.

9) Take care in wiring the circuit to avid loose connection.

10) Check for print short after soldering.

11) Please use resistance of the exact value as given in the circuit.

12) Check primary and secondary winding of the transformer before connecting.

13) The insulation of the wire inside the modes should be of good quality.

Applications:-

The biggest advantage of IVR for small and large organizations is to save time and money. IVR systems can take care of most of the frequently asked questions that an organization receives.

IVR systems have the advantage of making callers and customers feel like they're being attended to .

Another advantage is that IVR systems don't sleep. They don't take lunch breaks.They don't go on vacations to the Bahamas

This project is used for the college automation. If database of every student of every college under a university can be provided than it can be used for the whole university automation.

Softwares used:-

Microsoft visual basic 6.0 Express PCB for PCB designing Assembler for PIC16F876A microcontroller Program downloader

References:-

Books:

8051 and embedded system by Mazidi & Mazidi

Electronic devices and circuit theory

Electronic projects.

Microelectronic circuits.

Electronic for you.

Visual basic bible.

WEBSITES:

1) www.efyindia.com

2) www.nationalsemiconductor .com

3) www.electroprojectindia.com

4) www.alldatasheet.com

5) www.howstuffworks.com

6) www.datasheet.com

7) www.programmer’sheaven.com