PROJECT · PDF file · 2014-12-22We take an opportunity to present this project...

DTMF Controlled Robot

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PROJECT

Submitted in complete fulfillment of the requirements

for the degree of

BACHELOR OF ENGINEERING

BY

Ronak Khara

Rinku Rohira

Shantanu Khare

Sheetal Daldani

Under the Guidance of

PROF.MRS.Archana Singhi

(Internal Guide)

Mrs. Sunita Sharma

(Head of the Department)

DEPARTMENT OF ELECTRONICS

AND TELECOMMUNICATION ENGINEERING

WATUMULL INSTITUTE OF ELECTRONICS

ENGINEERING AND COMPUTER TECHNOLOGY, MUMBAI

UNIVERSITY OF MUMBAI

2011-2012


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WATUMULL INSTITUTE OF ELECTRONICS

ENGINEERING & COMPUTER TECHNOLOGY

AN AFFILIATE OF THE UNIVERSITY OF MUMBAI

CERTIFICATE

This is to certify that the following students have submitted the report for their final year

project on “DTMF Controlled Robot” under the guidance of Mrs. Archana Singhi in

partial fulfillment of requirement for the degree of Bachelor of Engineering (Electronics

and Telecommunication) of the University of Mumbai in the academic year 2011-2012.

Ronak Khara Rinku Rohira Shantanu Khare Sheetal Daldani

Internal Examiner External Examiner

Mrs. ARCHANA SINGHI Mrs. SUNITA SHARMA

Internal Guide Head of the Department

Mrs. SANDYA DESAI

Principal

Plot 47, DR. RG THADANI MARG,WORLI SEAFACE,WORLI,MUMBAI-400018.

INDIA

TEL : 91-22-2493 5281,2497 4858,2497 1506. FAX : 91-22-2491 5103

E-Mail :[email protected]


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ACKNOWLEDGEMENT

Among the wide panorama of people who provided us help and motivation to complete

our project, we are grateful in presenting to you the rare shades of technology by

documenting project DTMF Controlled Robot.

We wish to express our deep sense of gratitude to our Head Of Department Prof Mrs.

Sunita Sharma for giving us her precious hour to our endeavor. We gratefully

acknowledge her generous help in providing us with relevant information, data comments

and manuscripts. Her encouragement proved to be boon in the path of our achievement.

We are thankful to our guide, Mrs. Archana Singhi for giving us valuable inputs and

helped us directly or indirectly in the development of this project. We also thank lab

technician Vijayan sir and Prabhakar sir and other non teaching staff of our Electronics

and Telecommunication for their help during the development of this project.

We also thank our colleagues to help us make our project a success.

Above all we thank our principal Mrs. Sandya Desai for providing us the facilities to

bring a success.

Ronak Khara Rinku Rohira Shantanu Khare Sheetal Daldani


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PREFACE

We take an opportunity to present this project report on "DUAL TONE

MULTIPLE FREQUENCY (DTMF) CONTROLLED ROBOT" and put before

readers some useful information regarding our project.

We have made sincere attempts and taken every care to present this matter in

precise and compact form, the language being as simple as possible.

We are sure that the information contained in this volume would certainly prove

useful for better insight in the scope and dimension of this project in its true perspective.

The task of completion of the project though being difficulty was made quite

simple, interesting and successful due to deep involvement and complete dedication of

our group members.


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Index:

Sr no. Topic Page number

1 Introduction 1

2 Block Diagram 4

3 Circuit Diagram 10

4 Working of Circuit 13

5 Software Development 16

6 PCB Fabrication 23

7 Different Components used 27

8 Advantages & Disadvantages 38

9 Applications 40

10 Future Scope 43

11 Troubleshooting 45

12 Conclusion 47

13 Bibliography 49

14 Data Sheets 51


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Figure Index:

Sr no. Topic Page number

1 Circuit Image 3

2 Block Diagram 5

3 DTMF table 7

4 Circuit diagram 11

5 Network working 15

6 Microcontroller pin diagram 53

7 Microcontroller block diagram 54

8 Oscillator Connections 56

9 External Clock Drive Configuration 56


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DUAL TONE

MULTIPLE

FREQUENCY

(DTMF)

CONTROLLED

ROBOT


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CHAPTER 1:

INTRODUCTION


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1.1 DTMF CONTROLLED ROBOT :-

Conventionally, Wireless-controlled robots use RF circuits, which have the

drawbacks of limited working range, limited frequency range and the limited control.

Use of a mobile phone for robotic control can overcome these limitations. It provides

the advantage of robust control, working range as large as the coverage area of the

service provider, no interference with other controllers and up to twelve controllers.

Although the appearance and the capabilities of robots vary vastly, all robots share

the feature of a mechanical, movable structure under some form of control. The Control of

robot involves three distinct phases: perception, processing and action.

Generally, the preceptors are sensors mounted on the robot, processing is done by the

on-board microcontroller or processor, and the task is performed using motors or with

some other actuators.

Man has come long way In terms of development over a period of time we would use

the RF modules for the purpose wireless after that we overcome with the techniques of

GSM modems and we use the DTMF in wireless system.

The DTMF technology has overcome the problem of limitation which we can work

only in limited range or limited area was in RF technology by using cell phone (DTMF).

We can access our device or the robot as large as the working space of the service

provider, no interference with other controllers and up to 12 controls.


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1.2 TOP VEIW OF THE DTMF CONTROLLED ROBOT:-

Figure1.1- Circuit image


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CHAPTER 2:

BLOCK DIAGRAM


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2.1 BLOCK DIAGRAM OF DTMF CONTROLLED ROBOT:-

Figure2.1- Block diagram


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2.2 DESCRIPTION ABOUT BLOCK DIAGRAM:-

In this project the robot, is controlled by a mobile phone that makes call to the

mobile phone attached to the robot. In the course of the call, if any button is pressed, a

tone corresponding to the button pressed is heard at the other end of the call. This tone

is called ‘DUAL –TONE MULTIPLE-FREQUENCY’ (DTMF) tone. The robot

receives this DTMF tone with the help of phone stacked in the robot.

The received tone is processed by the atmega16 microcontroller with the help of

DTMF decoder MT8870. The decoder decodes the DTMF tone in to its equivalent

binary digit and this binary number is send to the microcontroller. The microcontroller

is preprogrammed to take a decision for any give input and outputs its decision to motor

drivers in order to drive the motors for forward or backward motion or a turn.

The mobile that makes a call to the mobile phone stacked in the robot acts as a

remote. So this simple robotic project does not require the construction of receiver and

transmitter units.

DTMF signaling is used for telephone signaling over the line in the voice

frequency band to the call switching center. The version of DTMF used for telephone

dialing is known as ‘Touch –Tone’.

DTMF assigns a specific frequency (consisting of two separate tones) to each key s

that it can easily be identified by the electronic circuit.

The signal generated by the DTMF encoder is the direct al-gebraic submission, in

real time of the amplitudes of two sine (cosine) waves of different frequencies, i.e.,

pressing ‘5’ will send a tone made by adding 1336Hz and 770Hz to the other end of the

mobile. The tones and assignments in a DTMF system shown below


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Figure2.2- DTMF table

2.3 DTMF BASICS:-

DTMF, or tone dialing, is very commonly used. DTMF (Dual-tone Multi

Frequency) is a tone composed of two sine waves of given frequencies. Individual

frequencies are chosen so that it is quite easy to design frequency filters, and so that they

can easily pass through telephone lines (where the maximum guaranteed bandwidth

extends from about 300 Hz to 3.5 kHz).

DTMF was not intended for data transfer; it is designed for control signals only.

With standard decoders, it is possible to signal at a rate of about 10 "beeps" (=5 bytes)

per second.

DTMF standards specify 50ms tone and 50ms space duration. For shorter lengths,

synchronization and timing becomes very tricky.


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2.4 DTMF USAGE: -

DTMF is the basis for voice communications control. Modern telephony uses

DTMF to dial numbers, configure telephone exchanges (switchboards), and so on.

Occasionally, simple floating codes are transmitted using DTMF - usually via a CB

transceiver (27 MHz). It is used to transfer information between radio transceivers, in

voice mail applications, etc.

Almost any mobile (cellular) phone is able to generate DTMF after establishing

connection. If your phone can't generate DTMF, you can use a stand-alone "dialer".

DTMF was designed so that it is possible to use acoustic transfer, and receive the codes

using standard microphone.

2.5 COMPOSITION OF DTMF signals:-

The table shows how to compose any DTMF code. Each code, or "beep",

consists of two simultaneous frequencies mixed together (added amplitudes). Standards

specify 0.7% typical and 1.5% maximum tolerance. The higher of the two frequencies

may have higher amplitude (be "louder") of 4 dB max.

This shift is called a "twist". If the twist is equal to 3 dB, the higher frequency is

3 dB louder. If the lower frequency is louder, the twist is negative.

Frequency table:

1209 Hz 1336 Hz 1477 Hz 1633 Hz

697 Hz 1 2 3 A

770 Hz 4 5 6 B

852 Hz 7 8 9 C

941 Hz * 0 # D


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This table resembles a matrix keyboard. The X and Y coordinates of each code

give the two frequencies that the code is composed of. Notice that there are 16 codes;

however, common DTMF dialers use only 12 of them. The "A" through "D" is "system"

codes. Most end users won't need any of those; they are used to configure phone

exchanges or to perform other special functions.

2.6 How to transmit and to decode DTMF:-

To transmit DTMF:

Most often, dedicated telephony circuits are used to generate DTMF (for

example, MT8880). On the other hand, a microprocessor can do it, too. Just connect a RC

filter to two output pins, and generate correct tones via software. However, getting the

correct frequencies often requires usage of a suitable Xtal for the processor itself - at the

cost of non-standard cycle length, etc. So, this method is used in simple applications only.

To decode DTMF:

It is not easy to detect and recognize DTMF with satisfactory precision. Often,

dedicated integrated circuits are used, although a functional solution for DTMF

transmission and receiving by a microprocessor (a PIC in most cases) exists. It is rather

complicated, so it is used only marginally. Most often, a MT 8870 or compatible circuit

would be used.

Most decoders detect only the rising edges of the sine waves. So, DTMF generated by

rectangular pulses and RC filters works reliably. The mentioned MT 8870 uses two 6th

order band pass filters with switched capacitors. These produce nice clean sine waves

even from distorted inputs, with any harmonics suppressed.


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CHAPTER 3:

CIRCUIT DIAGRAM


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3.1 CIRCUIT DIAGRAM OF MOBILE OPERATED

VEHICLE:

Figure3.1- Circuit diagram


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3.2 DESCRIPTION ABOUT CIRCUIT DIAGRAM:

A figure shows the block diagram and circuit diagram of the microcontroller-

based robot. The important components of this robot are DTMF decoder, Microcontroller

and motor driver.

An MT8870 series DTMF decoder is used here. All types of the mt8870 series use

digital counting techniques to detect and decode all the sixteen DTMF tone pairs in to a

four bit code output. The built -in dial tone rejection circuit eliminated the need for pre-

filtering. When the input signal given at pin2 (IN-) single ended input configuration is

recognized to be effective, the correct four bit decode signal of the DTMF tone is

transferred to Q1 (pin11) through Q4(pin14) outputs.

The ATmega 16 is a low power, 8 bit; CMOS microcontroller based on the

AVR enhanced RISC architecture. It provides the following feature: 16kb of in system

programmable flash memory with read write capabilities, 512bytes of EEPROM, 1KB

SRAM, 32 general purpose input/output lines. 32 general purpose working registers. All

the 32 registers are directly connected to the arithmetic logic unit, allowing two

independent registers to be accessed in one signal instruction executed in one clock cycle.

The resulting architecture is more code efficient.

Outputs from port pins PD0 through PD3 and PD7 of the microcontroller are

fed to inputs IN1 through IN4 and enable pins (EN1 and EN2) of motor driver L293d

respectively, to drive geared motors. Switch S1 is used for manual reset. The

microcontroller output is not sufficient to drive the DC motors, so currently drivers are

required for motor rotation.

The L293D is a quad, high current, half-H drive designed to provide

bidirectional drive currents of up to 600mA at voltage from 4.5V to 36V. It makes it

easier to drive the DC motors. Pins IN1 through IN4 and OUT1 through OUT4 are input

and out pins, respectively, of driver 1 through driver 4. Drivers 1 and 2, and Drivers 3 &

4 are enabled by enable pin 1 (EN1) and pin 9 (En2), respectively. When enable input

En1 (pin 1) is high, drivers 1 & 2 are enabled and the outputs corresponding to their

inputs are active. Similarly, enable input EN2 (pin9) enables drivers 3 and


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CHAPTER 4:

WORKING OF CIRCUIT


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4.1 Working:

In order to control the robot, you need to make a call to the cell phone attached to

the robot (through head phone) from any phone, which sends DTMF tunes on pressing

the numeric buttons. The cell phone in the robot is kept in ‘auto answer’ mode. If the

mobile does not have the auto answering facility, receive the call by ‘ok’ key on the

vehicle connected mobile end then made it in hands-free mode. So after a ring, the cell

phone accepts the call.

Now you may press any button on your mobile to perform actions as listed below:

When you press 1 the robot will move forward

When you press 4 the robot will move left

When you press 2 the robot will move backwards

When you press 3 the robot will move right

When you press 5 the robot will stop.

The DTMF tones thus produced are received by the cell phone in the robot.

These tones are fed to the circuit by the headset of the cell phone. The MT8870 decodes

the received tone and sends the equipment binary number to the microcontroller, the

robot starts moving.

When you press key ‘2’ (binary equivalent 00000010) on your mobile phone, the

microcontroller outputs ‘10001001’ binary equivalent. Port pins PD0, PD3 and Pd7 are

high. The high output at PD7 of the microcontroller drivers the motor driver (L293D).

Port pins PD0 and PD3 drive motors M1 and M2 in forward direction. Similarly,

motors M1 and M2 move for left turn, right turn, backward motion and stop

condition.


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4.2 Network working:

Figure 4.1- Network working


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CHAPTER 5:

SOFTWARE DEVLOPMENT


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5.1 SOFTWARE PROJECT MANAGEMENT PLAN

Conventionally, Wireless-controlled robots use RF circuits, which have the

drawbacks of limited working range, limited frequency range and the limited control. Use of

a mobile phone for robotic control can overcome these limitations.

It provides the advantage of robust control, working range as large as the coverage

area of the service provider, no interference with other controllers and up to twelve

controllers.

5.2 Project Deliverables:

The following are the deliverables of the Project:

1. GUIs made using Microsoft Visual Studio

2. Database using Microsoft Access

3. Executable Files.

4. DLL Files.

5. Help Files.

5.3 PROJECT ORGANIZATIONS

Software Process Model

The model used is Classic Life Cycle Model

The Project team is meeting once a week to discuss the progress made by each

member and to share the relevant information and be documents that have been

prepared. The number of meetings may increase during the final semester as the team

members will have more time.

There are reviews being conducted once a week during the team meetings. A

complete technical review will be conducted at the end of the Design Phase. There

will be reviews conducted at the completion of every testing phase.

The major milestones to be achieved are as follows:


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1. Results of research of existing system and discussions with the Project

leader.

2. Results of interview with experts and team meetings to finalize the

requirements of the software.

3. Results of the Design Phase, which include a number of modeling

diagrams, like the use cases, class diagrams, etc.

4. Results of the first coding phase will be an initial code that will be then

tested.

5. Based on the results of the testing, they code will be reviewed in the

second coding phase.

Tools and Techniques

We will require the following tools:

1. Microsoft Visual Studio 2005.

2. Microsoft Office 2003.

Tasks

The following tasks are to be executed:-

1. Requirement Analysis Phase 1

2. Requirement Analysis Phase 2

3. Design of System

4. Coding Phase 1

5. Coding Phase 2

6. Testing Phase 1


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Requirement analysis:

1. Requirement Analysis Phase 1:

This will include the research of existing software and a discussion with the Project

guide.

2. Requirement Analysis Phase 2:

Based on the above results, the project team will discuss and finalize the requirements

that are to be provided. We shall consult a number of experts during this phase. The

SPMP shall also be prepared during this phase.

Design Phase:

The design phase will involve the design of the static view, dynamic view, and the

functional view of the software. A number of diagrams including the Use case, class

diagram, activity diagram, and data flow diagrams will be used to model the software.

Also, the GUIs will be designed during this phase

Coding Phase 1:

The prerequisite to this phase is the study of Microsoft Visual basic6. After this

study, an initial code of the entire project will be written. Also, the database will be

created during this phase. Finally, we shall conduct unit tests.

Coding Phase 2:

This phase will include a review of the code created in Phase 1. After the review,

the necessary code and database will be modified to include the results of review.

Testing Phase:

We shall be following a testing program that will involve unit testing, integration

testing, and validation testing. More information will be known after further discussion.

5.4 SOURCE PROGRAM: ROBOT.C


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Include C \ \ Code \ BCD_lib.Lib

Include C \ \ Code \89Sxx.Lib

Include C \ \ Code \Variable.Lib

Main:

If P1.0 = 1 then

Gosub decode_data

End if

Goto main

Decode_data:

Portval [0] = P1.1

Portval [1] = P1.2

Portval [2] = P1.3

Portval [3] = P1.4

Waitms 100

Gousb check

Return

Check:

Select Case Portval

Case 1:

P0.0 = 0

P0.1 = 0

P0.2 = 0

P0.3 = 0

Waitms 50

Case 2:

P0.0 = 1

P0.1 = 0

P0.2 = 1

P0.3 = 0

Waitms 50


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Case 3:

P0.0 = 0

P0.1 = 1

P0.2 = 0

P0.3 = 1

Waitms 50

Case 4:

P0.0 = 1

P0.1 = 0

P0.2 = 0

P0.3 = 0

Waitms 50

Case 5:

P0.0 = 0

P0.1 = 0

P0.2 = 1

P0.3 = 0

Waitms 50

Case else

Goto main

End Select

Goto Main

P0.3 = 0

Wait 2

P0.0 = 0

P0.1 = 1

P0.2 = 0

P0.3 = 1

Wait 2

P0.0 = 0

P0.1 = 0


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P0.2 = 0

P0.3 = 0

Goto Main


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CHAPTER 6:

PCB FABRICATION


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6.1 P.C.B. MAKING

P.C.B. is printed circuit board which is of insulating base with layer of thin

copper-foil.

The circuit diagram is then drawn on the P. C. B. with permanent marker and then

it is dipped in the solution of ferric chloride so that unwanted copper is removed

from the P.C.B., thus leaving components interconnection on the board.

The specification of the base material is not important to know in most of the

application, but it is important to know something about copper foil which is

drawn through a thin slip.

The resistance of copper foil will have an affect on the circuit operation.

Base material is made of lamination layer of suitable insulating material such as

treated paper, fabric; or glass fibers and binding them with resin. Most commonly

used base materials are formed paper bonded with epoxy resin.

It is possible to obtain a range of thickness between 0.5 mm to 3 mm.

Thickness is the important factor in determining mechanical strength particularly

when the commonly used base material is “Formea” from paper assembly.

Physical properties should be self supporting these are surface resistivity, heat

dissipation, dielectric, constant, dielectric strength.

Another important factor is the ability to withstand high temperature.

6.2 DESIGNING THE LAYOUT

While designing a layout, it must be noted that size of the board should be as

small as possible.


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Before starting, all components should be placed properly so that an accurate

measurement of space can be made.

The component should not be mounted very close to each other or far away from

one another and neither one should ignore the fact that some component reed

ventilation, which considerably the dimension of the relay and transformer in

view of arrangement, the bolting arrangement is also considered.

The layout is first drawn on paper then traced on copper plate which is finalized

with the pen or permanent marker which is efficient and clean with etching.

The resistivity also depends on the purity of copper, which is highest for low

purity of copper. The high resistance paths are always undesired for soldered

connections.

The most difficult part of making an original printed circuit is the conversion

from, theoretical circuit diagram into wiring layout. Without introducing cross

over and undesirable effect.

Although it is difficult operation, it provides greaten amount of satisfaction

because it is carried out with more care and skill.

The board used for project has copper foil thickness in the range of 25 40 75

microns.

The soldering quality requires 99.99% efficiency.

It is necessary to design copper path extra large. There are two main reasons for

this.

i. The copper may be required to carry an extra large overall current.

ii. It acts like a kind of screen or ground plane to minimize the effect of interaction.

The first function is to connect the components together in their right sequence

with minimum need for interlinking i.e. the jumpers with wire connections.

It must be noted, that when layout is done, on the next day it should be dipped in

the solution and board is move continuously right and left after etching perfectly

the board is cleaned with water and is drilled.


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After that holes are drilled with 1 mm or 0.8 mm drill. Now the marker on the P.

C. B. is removed.

The Printed Circuit Board is now ready for mounting the components on it.

6.3 SOLDERING:

For soldering of any joints first the terminal to be soldered are cleaned to remove

oxide film or dirt on it. If required flux is applied on the points to be soldered.

Now the joint to be soldered is heated with the help of soldering iron. Heat

applied should be such that when solder wire is touched to joint, it must melt

quickly.

The joint and the soldering iron is held such that molten solder should flow

smoothly over the joint.

When joint is completely covered with molten solder, the soldering iron is re-

moved.

The joint is allowed to cool, without any movement.

The bright shining solder indicates good soldering.

In case of dry solder joint, an air gap remains in between the solder maternal and

the joint. It means that soldering is improper. This is removed and again soldering

is done.

Thus is this way all the components are soldered on P. C. B.


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CHAPTER 7:

Different Component Used


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7.1 Diodes:-

Diodes are components that allow current to flow in only one direction. They have a

positive side (leg) and a negative side. When the voltage on the positive leg is higher than

on the negative leg then current flows through the diode (the resistance is very low).

When the voltage is lower on the positive leg than on the negative leg then the current

does not flow (the resistance is very high). The negative leg of a diode is the one with the

line closest to it. It is called the cathode. The positive end is called the anode.

7.2 LED:-

Light Emitting Diodes are great for projects because they provide visual entertainment.

LEDs use a special material which emits light when current flows through it. Unlike light

bulbs, LEDs never burn out unless their current limit is passed. A current of 0.02 Amps

(20 mA) to 0.04 Amps (40 mA) is a good range for LEDs. They have a positive leg and a

negative leg just like regular diodes. To find the positive side of an LED, look for a line

in the metal inside the LED. It may be difficult to see the line. This line is closest to the

positive side of the LED. Another way of finding the positive side is to find a flat spot on

the edge of the LED. This flat spot is on the negative side.

When current is flowing through an LED the voltage on the positive leg is about 1.4

volts higher than the voltage on the negative side. Remember that there is no resistance to

limit the current so a resistor must be used in series with the LED to avoid destroying it.

Now we know enough that we can start to build circuits. But first we will look a little

closer at a component that was introduced in Section 1.2.

The LED


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An LED is the device shown above. Besides red, they can also be yellow, green and

blue. The letters LED stand for Light Emitting Diode. If you are unfamiliar with diodes,

take a moment to review the components in Basic Components, Section 1.2. The

important thing to remember about diodes (including LEDs) is that current can only flow

in one direction.

To make an LED work, you need a voltage supply and a resistor. If you try to use an

LED without a resistor, you will probably burn out the LED. The LED has very little

resistance so large amounts of current will try to flow through it unless you limit the

current with a resistor. If you try to use an LED without a power supply, you will be

highly disappointed.

7.3 Resistors:-

Resistors are components that have a predetermined resistance. Resistance

determines how much current will flow through a component. Resistors are used to

control voltages and currents. A very high resistance allows very little current to flow.

Air has very high resistance. Current almost never flows through air. (Sparks and

lightning are brief displays of current flow through air. The light is created as the current

burns parts of the air.) A low resistance allows a large amount of current to flow. Metals

have very low resistance. That is why wires are made of metal. They allow current to

flow from one point to another point without any resistance. Wires are usually covered

with rubber or plastic. This keeps the wires from coming in contact with other wires and

creating short circuits. High voltage power lines are covered with thick layers of plastic

to make them safe, but they become very dangerous when the line breaks and the wire is

exposed and is no longer separated from other things by insulation.

Resistance is given in units of ohms. (Ohms are named after Mho Ohms who

played with electricity as a young boy in Germany.) Common resistor values are from

100 ohms to 100,000 ohms. Each resistor is marked with colored stripes to indicate its

resistance. To learn how to calculate the value of a resistor by looking at the stripes on

the resistor, go to Resistor Values which includes more information about resistors.

Variable Resistors

http://www.iguanalabs.com/resistors.htm


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Variable resistors are also common components. They have a dial or a knob that

allows you to change the resistance. This is very useful for many situations. Volume

controls are variable resistors. When you change the volume you are changing the

resistance which changes the current. Making the resistance higher will let less current

flow so the volume goes down. Making the resistance lower will let more current flow so

the volume goes up. The value of a variable resistor is given as its highest resistance

value. For example, a 500 ohm variable resistor can have a resistance of anywhere

between 0 ohms and 500 ohms. A variable resistor may also be called a potentiometer

(pot for short).

7.4 The Capacitor:-

If you already understand capacitors you can skip this part.

The picture above on the left shows two typical capacitors. Capacitors usually have two

legs. One leg is the positive leg and the other is the negative leg. The positive leg is the

one that is longer. The picture on the right is the symbol used for capacitors in circuit

drawings (schematics). When you put one in a circuit, you must make sure the positive

leg and the negative leg go in the right place. Capacitors do not always have a positive

leg and a negative leg.

The smallest capacitors in this kit do not. It does not matter which way you put them in

a circuit.

A capacitor is similar to a rechargeable battery in the way it works. The difference is

that a capacitor can only hold a small fraction of the energy that a battery can. (Except for

really big capacitors like the ones found in old TVs.) These can hold a lot of charge. Even

if a TV has been disconnected from the wall for a long time, these capacitors can still

make lots of sparks and hurt people.) As with a rechargeable battery, it takes a while for

the capacitor to charge. So if we have a 12 volt supply and start charging the capacitor, it


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will start with 0 volts and go from 0 volts to 12 volts. Below is a graph of the voltage in

the capacitor while it is charging.

The same idea is true when the capacitor is discharging. If the capacitor has been

charged to 12 volts and then we connect both legs to ground, the capacitor will start

discharging but it will take some time for the voltage to go to 0 volts. Below is a graph of

what the voltage is in the capacitor while it is discharging.

We can control the speed of the capacitor's charging and discharging using resistors.

Capacitors are given values based on how much electricity they can store. Larger

capacitors can store more energy and take more time to charge and discharge. The values

are given in Farads but a Farad is a really large unit of measure for common capacitors.

In this kit we have 2 33pf capacitors, 2 10uf capacitors and 2 220uF capacitors. Pf means

picofarad and uf means microfarad. A picofarad is 0.000000000001 Farads. So the 33pf

capacitor has a value of 33 picofarad or 0.000000000033 Farads. A microfarad is

0.000001 Farads. So the 10uf capacitor is 0.00001 Farads and the 220uF capacitor is

0.000220 Farads. If you do any calculations using the value of the capacitor you have to

use the Farad value rather than the picofarad or microfarad value.

Capacitors are also rated by the maximum voltage they can take. This value is always

written on the larger can shaped capacitors. For example, the 220uF capacitors in this kit

have a maximum voltage rating of 25 volts. If you apply more than 25 volts to them they

will die.


39

7.5 Volt Power Supply: -

Most digital logic circuits and processors need a 5 volt power supply. To use these

parts we need to build a regulated 5 volt source. Usually you start with an unregulated

power supply ranging from 9 volts to 24 volts DC. To make a 5 volt power supply, we

use a LM7805 voltage regulator IC (Integrated Circuit). The IC is shown below.

The LM7805 is simple to use. You simply connect the positive lead of your unregulated

DC power supply (anything from 9VDC to 24VDC) to the Input pin, connect the

negative lead to the Ground pin and then when you turn on the power, you get a 5 volt

supply from the Output pin. This 5 volt output will be used as Vcc in the following

projects.

Connect the red wire from the power supply adapter to the input of the 7805.

Connect the black wire from the power supply adapter to the ground row (with the blue

line beside it). Run a black jumper wire from the ground row to the ground of the 7805.

Then use a yellow jumper to connect the 5 v output to the row of holes with the red stripe

beside it.


40

7.6 DC MOTOR:-

Introduction:

This page describes how DC motors work, and how we can use them to build the

traction system of a robot. It covers both permanent magnet motors, and series wound

motors (such as car starter motors). If you are interested in converting a starter motor for

use in a robot, see the separate page Converting starter motors.

Motor principles:

All motors require two magnetic fields, one produced by the stationary part of the

motor (the stator, or field), and one by the rotating part (the rotor, or armature). These

are produced either by a winding of coils carrying a current, or by permanent magnets. If

the field is a coil of wire, this may be connected in a variety of ways, which produces

different motor characteristics.

The basic law of a motor, the reason why they rotate, is governed by Fleming’s left hand

rule (see figure below). This tells you the direction of the force on a wire that is carrying

current when it is in a magnetic field.

http://homepages.which.net/~paul.hills/Motors/Starters/Starters.html


41

The next diagram shows the force acting on a wire carrying current, obeying the left hand

rule:

If we now bend the wire round in a loop, and place it in a magnetic field caused by two

permanent magnets, we have the situation shown in the diagram below. Here, both sides

of the wire loop will have a force on them, trying to make the wire loop rotate. The

current is applied to the loop through the commutator, which is shown as two pieces of

metal formed into a ring in the figure. Current is applied to the commutator by stationary

graphite blocks, called brushes, which rub against the commutator ring.

The loop will continue to rotate anticlockwise (as we see it in the figure) until it is

vertical. At this point, the stationary brushes won't be applying current around the loop

any more because they will be contacting the gap between the commutator segments, but

the inertia of the loop keeps it going a little more, until the DC supply reconnects to the


42

commutator segments, and the current then goes around the loop in the opposite

direction. The force though is still in the same direction, and the loop continues to rotate.

This is how DC motors work. In a real motor, there are many wire loops (windings) all at

varying angles around a solid iron core. Each loop has its own pair of commutator

segments. This block of core and wire loops is called the rotor because it rotates, or the

armature.

7.7 Crystal Oscillator:-

This is how some oscillator looks like.


43

Short description:

Crystals are commonly used to provide a stable clock source for micro-controllers. This

has a freq. tolerance of +-50ppm, temperature stability of +-50ppm, and load capacitance

of 18pF. It's slightly more than 1/8" tall.

More information and instructions:

Here are 22pF ceramic disc capacitors commonly used with this crystal to provide a

clock source to micro-controllers.

When installing, be sure that the case does not make contact with any other

conductors; i.e., don't push it all the way flush with the board.

+-5ppm (parts per million) per year aging drift.

About crystals:

There are several different ways to provide a clock source, including crystals,

oscillators, RC circuits, and resonators; this article gives a good comparison. Crystals

offer a good compromise of low cost, high accuracy, good temperature stability, and low

power use.

They are typically used in what's called a "Pierce circuit" with microcontrollers that

has two other capacitors tied to ground on either side of the crystal. The value of the

capacitors affects the circuit's frequency. Crystals manufactured for use in this type of

circuit are parallel crystals and come pre-compensated for a certain "capacitive load." The

formula that relates the crystal's capacitive load and the capacitors used in the circuit is:

CL = (C1*C2)/ (C1+C2) + Cs (stray capacitance in leads and circuit board). Many guides

suggest Cs is usually around 5 pF, but the Microchip spec sheets seem to assume its

12.5pF.

PPM (Parts per Million):

This is like a percent error (1000 PPM = .1% error), and is convenient for calculating

error with crystals. 5ppm on a 4MHz crystal = 5*4 = 20Hz possible error. Most

http://www.curiousinventor.com/store/product/61

http://www.maxim-ic.com/appnotes.cfm/an_pk/2154


44

microcontroller applications don't require too much accuracy, 100ppm is fine. If the

parallel capacitors don't match the crystal's capacitive load exactly, they will pull the

frequency, but not much. This offers more info about pull ability and crystals in general.

It seems to indicate that on a 20pF CL crystal, you may get 16ppm/pF error between the

anticipated load and actual.

A Microchip application note that talks about crystal design considerations for

microcontrollers.

http://www.ecsxtal.com/store/pdf/quar_des.pdf

http://ww1.microchip.com/downloads/en/AppNotes/FACT001.PDF


45

CHAPTER 8:

ADVANTAGES AND

DISADVANTAGES


46

Advantages:

- DTMF’s technology is simple, low cost, as well as its already popular status

in the telephone industry of today.

In the networks there are large number of nodes that are very simple and act

merely as relay stations.

In healthcare (hospital and home environments), a robot that is capable of

sending acoustic commands to turn on/off devices such as light switch or

closing door while letting the user know that the process is taking place will

be very helpful in allowing the user to feel more comfortable around robots.

Disadvantages:

As signal strength decreases the performance of the system also degrades


47

Chapter 9:

Applications


48

Applications:-

Scientific

• Remote control vehicles have various scientific uses including hazardous

environments, working in the deep ocean , and space exploration. The majority of

the probes to the other planets in our solar system have been remote control

vehicles, although some of the more recent ones were partially autonomous. The

sophistication of these devices has fueled greater debate on the need for manned

spaceflight and exploration.

Military and Law Enforcement

• Military usage of remotely controlled military vehicles dates back to the first

half of 20th century. Soviet Red Army used remotely controlled Teletanks during

1930s in the Winter War and early stage of World War II.

Search and Rescue

• UAVs will likely play an increased role in search and rescue in the United

States. This was demonstrated by the successful use of UAVs during the 2008

hurricanes that struck Louisiana and Texas.

Recreation and Hobby

• See Radio-controlled model. Small scale remote control vehicles have long been

popular among hobbyists. These remote controlled vehicles span a wide range in


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terms of price and sophistication. There are many types of radio controlled

vehicles. These include on-road cars, off-road trucks, boats, airplanes, and even

helicopters. The "robots" now popular in television shows such as Robot Wars,

are a recent extension of this hobby (these vehicles do not meet the classical

definition of a robot; they are remotely controlled by a human).


50

CHAPTER 10:

Future Scope


51

Future Scope:

IR Sensors

• IR sensors can be used to automatically detect & avoid obstacles if the robot

goes beyond line of sight. This avoids damage to the vehicle if we are

maneuvering it from a distant place.

Password Protection

• Project can be modified in order to password protect the robot so that it can be

operated only if correct password is entered. Either cell phone should be password

protected or necessary modification should be made in the assembly language

code. This introduces conditioned access & increases security to a great extent.

Alarm Phone Dialer

• By replacing DTMF Decoder IC CM8870 by a 'DTMF Transceiver IC’

CM8880, DTMF tones can be generated from the robot. So, a project called

'Alarm Phone Dialer' can be built which will generate necessary alarms for

something that is desired to be monitored (usually by triggering a relay). For

example, a high water alarm, low temperature alarm, opening of back window,

garage door, etc.

• When the system is activated it will call a number of programmed numbers to let

the user know the alarm has been activated. This would be great to get alerts of

alarm conditions from home when user is at work.


52

CHAPTER 11:

Troubleshooting


53

Troubleshooting:

During our final year full time project we had to par many hurdles to complete our

project we tackled it with the help of our mentor and with our knowledge with finally

helped us to get the project done.

The different problems we faced were:-

While etching the PCB the due to some mishandling the tracks on the PCB were not

properly etched and so we had to etch the PCB again.

While soldering the circuit it led to overheating of the IC MT8870 and due to which the

IC got fused. So we replaced the IC to get our project working.

Due to improper connections the robot was operating in the reverse operations so we

changed the wiring of it and it started operating.

The tuning in the camera was not happening properly so remedy to it was removed by

changing the connectors to the camera transreciever.


54

CHAPTER 12:

Conclusion


55

Conclusion:-

This paper has described the design and implementation of experiments to

test the feasibility of using the Dual Tone Multi-Frequency encoding scheme

as a method for communicating simple messages.


56

CHAPTER 13:

Bibliography


57

Books:

Robotics Demystified

Hardware Hacking Projects

Parallel Port Complete

Electric Drives

Websites: www.epanorama.com

www.robotics.com

www.automation.com

www.mechtechworld.com

http://www.epanorama.com/

http://www.robotics.com/

http://www.automation.com/

http://www.mechtechworld.com/


58

CHAPTER 14:

DATA SHEET


59

MICROCONTROLLER AT89SXX

Features

• 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

1. 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 power-ful microcomputer which provides a highly-flexible and

cost-effective solution to many embedded control applications. The AT89C2051


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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, on-chip

oscillator and clock circuitry. In addition, the AT89C2051 is designed with static

logic for opera-tion 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.

2. Pin Configuration

2.1 20-lead PDIP/SOIC

Figure 14.1- Microcontroller pin diagram


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3. Block Diagram

Figure 14.2- Microcontroller block diagram

4. Pin Description

4.1 VCC Supply voltage.

4.2 GND Ground.


62

4.3 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 on-chip precision analog comparator. The Port

1 out-put 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 pull-ups. Port 1 also receives

code data during Flash programming and verification.

4.4 Port 3 Port 3 pins P3.0 to P3.5, P3.7 are seven bi-directional I/O pins with

internal pull-ups. P3.6 is hard-wired as an input to the output of the on-

chip comparator and is not accessible as a gen-eral-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. Port 3 also serves the functions of various

special features of the AT89C2051 as listed below: Port 3 also receives

some control signals for Flash programming and verification.

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

4.5 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.

4.6 XTAL1 Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

4.7 XTAL2 Output from the inverting oscillator amplifier.


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5. Oscillator Characteristics

The XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier

which can be configured for use as an on-chip oscillator, as shown in Figure 5-1. Either a

quartz crystal or ceramic resonator may be used. To drive the device from an external

clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in

Figure 5-2. There are no require-ments on the duty cycle of the external clock signal,

since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but

minimum and maximum voltage high and low time specifications must be observed.

Figure 5-1-Oscillator Connections

Note: C1, C2 = 30 pF ± 10 pF for Crystals

= 40 pF ± 10 pF for Ceramic Resonators

Figure 14.3-External Clock Drive Configuration


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MT8870D/MT8870D-1

Integrated DTMF Receiver

Features:

• Complete DTMF Receiver

• Low power consumption

• Internal gain setting amplifier

• Adjustable guard time

• Central office quality

• Power-down mode

• Inhibit mode

• Backward compatible with MT8870C/MT8870C-1

Applications:

• Receiver system for British Telecom (BT) or CEPT Spec (MT8870D-1)

• Paging systems

• Repeater systems/mobile radio

• Credit card systems

• Remote control

Description:

The MT8870D/MT8870D-1 is a complete DTMF Receiver integrating both the band

split filter and Digital decoder functions. The filter section uses Switched capacitor

techniques for high and low Group filters; the decoder uses digital counting Techniques

to detect and decode all 16 DTMF tone pairs Into a 4-bit code. External component count


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is Minimized by on chip provision of a differential input Amplifier, clock oscillator and

latched three-state bus Interface.

Ordering Information

MT8870DE/DE-1 18 Pin Plastic DIP

MT8870DS/DS-1 18 Pin SOIC

MT8870DN/DN-1 20 Pin SSOP

-40 °C to +85 °C


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L293D

PUSH-PULL FOUR CHANNELS DRIVER WITH DIODES:

-600mA OUTPUT CURRENT CAPABILITY PER CHANNEL

-1.2A PEAK OUTPUT CURRENT (non repetitive) PER CHANNEL

-ENABLE FACILITY

-OVER TEMPERATURE PROTECTION

-LOGICAL”0” INPUT VOLTAGE UP TO 1.5 V(HIGH NOISE IMMUNITY)

-INTERNAL CLAMP DIODES

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 solenoids, DC 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.

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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LM78LXX Series

3-Terminal Positive Regulators

General Description

The LM78LXX series of three terminal positive regulators is available with several

fixed output voltages making them Useful in a wide range of applications. When used as

a zener diode/resistor combination replacement, the LM78LXX usually results in an

effective output impedance improvement of two orders of magnitude, and lower

quiescent current.

These regulators can provide local on card regulation, eliminating the distribution

problems associated with single point regulation. The voltages available allow the

LM78LXX to be used in logic systems, instrumentation, HiFi, and other solid state

electronic equipment.

The LM78LXX is available in the plastic TO-92 (Z) package, the plastic SO-8 (M)

package and a chip sized package (8-Bump micro SMD) using National’s micro SMD

package technology. With adequate heat sinking the regulator can deliver 100mA output

current. Current limiting is included to limit the peak output current to a safe value. Safe

area protection for the output transistors is provided to limit internal power dissipation. If

internal power dissipation becomes too high for the heat sinking provided, the thermal

shutdown circuit takes over preventing the IC from overheating.

Features:

- LM78L05 in micro SMD package

- Output voltage tolerances of ±5% over the temperature range

- Output current of 100mA

- Internal thermal overload protection

- Output transistor safe area protection

- Internal short circuit current limit

- Available in plastic TO-92 and plastic SO-8 low profile Packages

- Output voltages of 5.0V, 6.2V, 8.2V, 9.0V, 12V, 15V

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