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Transcript of Dual tone multiple frequency
Neeraj Khatri Page 1 (926/ECE/10)
ON
EMBEDDED SYSTEM AND ROBOTICS (PLC Institute of Electronics ,Rohini ,Delhi)
SUBMITTED TO: – SUBMITTED BY:– Mr. Tajender Malik Neeraj Khatri (H.O.D.:– ECE Deptt.) (926/ECE/10)
(ECE Department)
Neeraj Khatri Page 2 (926/ECE/10)
ACKNOWLEDGEMENT
I would like to add a few heartfelt words for the people who were part of
this training report in numerous ways. People who gave unending support right from the stage of training report idea were conceived. In particular, I
am extremely grateful to PLC INSTITUTE OF ELECTRONICS ,
Rohini ,Delhi for providing me with an excellent opportunity of undergoing summer training for the duration of six weeks.
I express my effusive thanks to Mr. B.P. ARUN (Teacher & Mentor) and other staff members. With their expert guidance and kind help this training
would have been a distant dream.
Finally a special thanks to all the Members of PLCIE, Rohini, Delhi Who
help me lot to carried out the project report and to compete my training
successfully.
Last but not the least; I thank my teacher, friends and my family members
for their constant encouragement.
NEERAJ KHATRI
(926/ECE/10)
Neeraj Khatri Page 3 (926/ECE/10)
PREFACE
Industrial training is must for every student pursuing professional degree because the ultimate goal of every student is to get the information the
industrial training helps us to get an idea of things.
We should known in order to get a good job i.e. have a good professional
carrier. Industrial training teaches us a lot of things. It helps us to know the
kind of environment we would be getting in an industry and help us to get with the kind of environment.
Industrial training helps us to know what kind of grade an engineer of specific branch plays in an industry. It help us to get used to working in
groups of known people in it teach us team work because my work in
industrial is accomplished by a group and not an individual.
In totality the industrial teaches us industrial ethics. Some advance technical
knowledge how and help us to acquired with industrial working style.
Neeraj Khatri Page 4 (926/ECE/10)
CONTENTS
S.No. Topic Page
1. Introduction 5
2. Technology Used 9
3. Electronics Part 14
4. Mechanical Part 31
5. Software Part 36
6. Snapshot 39
7. Conclusion 44
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INTRODUCTION
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INTRODUCTION :
Radio control (often abbreviated to R/C or simply RC) is the use of
radio signals to remotely control a device. The term is used
frequently to refer to the control of model vehicles from a hand-held
radio transmitter. Industrial, military, and scientific research
organizations make [traffic] use of radio-controlled vehicles as well. A remote control vehicle is defined as any mobile device that is controlled
by a means that does not restrict its motion with an origin external to
the device. This is often a radio control device, cable between control
and vehicle, or an infrared controller. A remote control vehicle (Also
called as RCV) differs from a robot in that the RCV is always
controlled by a human and takes no positive action autonomously. One of the key technologies which underpin this field is that of remote
vehicle control. It is vital that a vehicle should be capable of proceeding
accurately to a target area; maneuvering within that area to fulfill its
mission andreturning equally accurately and safely to base.
Recently, Sony Ericsson released a remote control car that could be
controlled by any Bluetooth cell phone. Radio is the most popular
because it does not require the vehicle to be limited by the length of
the cable or in a direct line of sight with the controller (as with the
infrared set-up). Bluetooth is still too expensive and short range to be
commercially viable.
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EMBEDDED SYSTEM:
An embedded system is a computer system designed for specific
control functions within a larger system, often with real-time computing
constraints.It is embedded as part of a complete device often including
hardware and mechanical parts. By contrast, a general-purpose
computer, such as a personal computer (PC), is designed to be flexible
and to meet a wide range of end-user needs. Embedded systems control
many devices in common use today.
Embedded systems contain processing cores that are typically eithermicrocontrollers or digital signal processors (DSP).The key
characteristic, however, is being dedicated to handle a particular task.
Since the embedded system is dedicated to specific tasks, design engineers can optimize it to reduce the size and cost of the product and
increase the reliability and performance. Some embedded systems are
mass-produced, benefiting fromeconomies of scale.
Physically, embedded systems range from portable devices such
as digital watches and MP3 players, to large stationary installations
like traffic lights,factory controllers, or the systems controlling nuclear power plants. Complexity varies from low, with a
single microcontroller chip, to very high with multiple
units, peripherals and networks mounted inside a large chassis or enclosure.
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CHARACTERISTICS
Embedded systems are designed to do some specific task, rather than be a general-purpose computer for multiple tasks. Some also have real-
time performance constraints that must be met, for reasons such as
safety and usability; others may have low or no performance requirements, allowing the system hardware to be simplified to reduce
costs.
Embedded systems are not always standalone devices. Many embedded
systems consist of small, computerized parts within a larger device that
serves a more general purpose. For example, the Gibson Robot Guitar features an embedded system for tuning the strings, but the
overall purpose of the Robot Guitar is, of course, to play music.
Similarly, an embedded system in an automobile provides a specific function as a subsystem of the car itself.
The program instructions written for embedded systems are referred to as firmware, and are stored in read-only memory or Flash memory chips.
They run with limited computer hardware resources: little memory,
small or non-existent keyboard or screen
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TECHNOLOGY USED
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TECHNOLOGY USED
Dual-Tone Multi-Frequency
(DTMF): Dual-tone multi-frequency (DTMF) signaling is used for
telecommunication signaling over analog telephone lines in the
voice-frequency band between telephone handsets and other
communications devices and the switching center. The version of
DTMF used for telephone tone dialing is known by the
trademarked term Touch-Tone (canceled March 13,1984), and
is standardized by ITU-T Recommendation . It is also known in the
UK as MF4. Other multi-frequency systems are used for
signaling internal to the Telephone network. As a method of in-band signaling, DTMF tones were also used by
cable television broadcasters to indicate the start and stop times of
local commercial insertion points during station breaks for the
benefit of cable companies. Until better out-of-band signaling
equipment was developed in the 1990s, fast, unacknowledged, and
loud DTMF tone sequences could be heard during the commercial
breaks of cable channels in the United States and elsewhere.
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Telephone Keypad The contemporary keypad is laid out in a 3x4 grid, although the
original DTMF keypad had an additional column for four now-
defunct menu selector keys. When used to dial a telephone
number, pressing a single key will produce a pitch consisting of two
simultaneous pure tone sinusoidal frequencies. The row in which the
key appears determines the low frequency, and the column
determines the high frequency. For example, pressing the
[1] key will result in a sound composed
of both a 697 and a 1209 hertz (Hz) tone. The original
keypads had levers inside, so each button activated two contacts.
The multiple tones are the reason for calling the system
multifrequency. These tones are then decoded by the switching center
to determine which key was pressed.
A DTMF Telephone Keypad
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DTMF Keypad Frequencies (With Sound Clips)
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
DTMF Event Frequencies
Event Low Freq. High Freq.
Busy Signal 480 Hz 620 Hz
Dial Tone 350 Hz 440 Hz
Ringback Tone(US)
440 Hz 480 Hz
Tones #, *, A, B, C, and D The engineers had envisioned phones being used to access
computers, and surveyed a number of companies to see
what they would need for this role. This led to the addition of
the number sign (#, sometimes called !octothorpe! in this
context) and asterisk or ’star’ (*) keys as well as a group of keys
Neeraj Khatri Page 13 926/ECE/10
for menu selection: A, B, C and D. In the end, the lettered keys were
dropped from most phones, and it was many years before these
keys became widely used for vertical service codes such as *67
in the United States and Canada suppress caller ID.
The U.S. military also used the letters, relabeled, in their now
defunct Autovon phone system. Here they were used before
dialing the phone in order to give some calls priority, cutting
in over existing calls if need be. The idea was to allow important
traffic to get through every time. The levels of priority available were
Flash Override (A), Flash (B), Immediate (C), and Priority (D), with
Flash Override being the highest priority.
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ELECTRONICS
PART
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ELECTRONICS PART
BLOCK DIAGRAM:
ELECTRONICS CIRCUIT AND MATERIAL USED ARE
1. H-BRIDGE
L293 IC
IC BASE
1 RESISTANCE (1K ohm)
1 LED
2. DTMF DECODER
MT 8870DE IC
IC BASE
3.57954 MHZ CRYSTAL
RESISTANCE
CERAMIC CAPACITORS
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LED
3. 8051 MICROCONTROLLER
IC BASE
LED’S
SWITCH
DIODES
CAPACITORS
RESISTANCE
VOLTAGE REGULATOR
11.0592 QUARTZ CRYSTAL
DESCRIPTION OF THE COMPONENTS USED IN
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THIS PROJECTS :
RESISTORS:
Resistors restrict the flow of electric current, for example a resistor is
placed in series with a light-emitting diode (LED) to limit the current
passing through the LED.
Resistance is measured in ohms, the symbol for ohm is an omega .
1 is quite small so resistor values are often given in k and M .
1 k = 1000 1 M = 1000000 .
CAPACITOR :
Neeraj Khatri Page 18 926/ECE/10
Capacitors store electric charge. They are used with resistors
in timing circuits because it takes time for a capacitor to fill with charge.
They are used to smooth varying DC supplies by acting as a reservoir of
charge. They are also used in filter circuits because capacitors easily
pass AC (changing) signals but they block DC (constant) signals.
Capacitance
This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is
measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values.
Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico):
µ means 10-6
(millionth), so 1000000µF = 1F
n means 10-9
(thousand-millionth), so 1000nF = 1µF
p means 10-12
(million-millionth), so 1000pF = 1Nf
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DIODES:
Diodes allow electricity to flow in only one direction. The arrow of the
circuit symbol shows the direction in which the current can flow. Diodes are the electrical version of a valve and early diodes were actually called
valves.
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CRYSTAL OSCILLATOR:
A crystal oscillator is an electronic oscillator circuit that uses the
mechanical resonance of a vibrating crystal of piezoelectric material to
create an electrical signal with a very precise frequency. This frequency
is commonly used to keep track of time (as in quartz wristwatches), to
provide a stable clock signal for digital integrated circuits, and to
stabilize frequencies for radio transmitters and receivers. The most
common type of piezoelectric resonator used is the quartz crystal, so
oscillator circuits designed around them became known as "crystal
oscillators."
3.57954 MHz CRYSTAL
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H-BRIDGE:
L293D is a dual H-Bridge motor driver. So with one IC, two DC motors
can be interfaced which can be controlled in both clockwise and counter clockwise directions and its direction of motion can also be fixed. The
four I/O’s can be used to connect up to four DC motors. L293D has
output current of 600mA and peak output current of 1.2A per channel. Moreover for the protection of the circuit from back EMF,
output 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. The name "H-Bridge" is derived from the actual
shape of the switching circuit which controls the motion of the motor. It
is also known as "Full Bridge".
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SNAPSHOT OF H-BRIDGE:
PCB OF H-BRIDGE:
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8870 DTMF DECODER:
MT8870DE IC
DTMF KIT
INTRODUCTION:
DTMF means DUAL TONE MULTIPLE FREQUENCY .This technology is widely used and has many applications. One of the application is discussed that is mobile controlled robotic car using DTMF technology . Being able to achieve reliable communication is an important open area of research to robotics as well as other technology areas. As interest in robotics continues to grow, robots are increasingly being integrated in everyday life. The results of this integration are end-users possessing less and less technical knowledge of the technology. Currently, the primary mode for robot communication uses RF (radio frequency). RF is an obvious choice for communication since it allows more. Information to be transferred at smaller distance. The overall goal of the project is to control robot over a long distance using DTMF technology efficiently.
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Description The transmitter side is placed in the area which is to be supervised. The receiver section is placed in the operator side which receives the video from the corresponding area.
DTMF TONE :
The DTMF technique outputs distinct representation of 16 common
alphanumeric characters (0-9, A-D, *, #) on the telephone. The lowest
frequency used is 697Hz and the highest frequency used is 1633Hz, as shown in Table.
Neeraj Khatri Page 25 926/ECE/10
The DTMF keypad is arranged such that each row will have its own
unique tone frequency and also each column will have its own unique
tone frequency. Above is a representation of the typical DTMF keypad and the associated row/column frequencies. By pressing a key, for
example 5, will generate a dual tone consisting of 770 Hz for the low
group and 1336 Hz for the high group.
DTMF Decoder:
The MT-8870 is a DTMF Receiver that integrates both band split filter
and decoder functions into a single 18-pin DIP or SOIC package. It is
manufactured using CMOS process technology. The MT-8870 offers low power consumption (35 mW max) and precise data handling.
Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital
counting techniques to detect and decode all 16 DTMF tone pairs into a
Neeraj Khatri Page 26 926/ECE/10
4-bit code. External component count is minimized by provision of an
on-chip differential input amplifier, clock generator, and latched tri-state interface bus. Minimal external components required includes a low-cost
3.579545 MHz color burst crystal, a timing resistor, and a timing
capacitor.
The filter section is used for separation of the low-group and high group
tones and it is achieved by applying the DTMF signal to the inputs of two sixth order switched capacitor band pass filters, the bandwidths of
which corresponds to the low and high group frequencies. The filter
section also incorporates notches at 350 and 440 Hz for exceptional dial tone rejection. Each filter output is followed by a single order switched
capacitor filter section which smoothes the signals prior to limiting.
Limiting is performed by high-gain comparators which are provided with hysteresis to prevent detection of unwanted low-level signals. The
outputs of the comparators provide full rail logic swings at the
frequencies of the incoming DTMF signals. Following the filter section is a decoder employing digital counting techniques to determine the
frequencies of the incoming tones and to verify that they correspond to
the standard DTMF frequencies.
CIRCUIT DIAGRAM
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SNAPSHOT OF DTMF:
:
PCB OF DTMF:
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8051 MICROCONTROLLER(AT89S52):
Brain of the DTMF
40 Pin IC
Actually a small computer Fitted on the Robot.
Has Internal RAM , ROM , Microprocessor , Input/output buses , timer , counter and many other things.
Code is burned on this IC and Processing is also done here.
It has 4 Ports : P0 , P1 , P2 , P3 are shown on next page.
Ecah port has 8 Bit.
Crystal Oscillator Provides external Frequency.
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SNAPSHOT OF 8051 MICROCONTROLLER:
PCB OF 8051 MICROCONTROLLER:
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MECHANICAL
PART
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MECHANICAL PARTS:
S.No. Component
Quantity
Dimension
1. Chassis 1 L*B (in inches)
9*7
2. Wheel 2 Diameter (in
cm)7
3. Nut 7 2-4 inches long
4. Bolt 13 As per the
dimension of
the nut
5. Clamps 2 As per the size
of dc motor
6. Caster wheel 1 Diameter
(in cm) 3
7. DC motor 2 12 volt 100 rpm
Neeraj Khatri Page 33 926/ECE/10
DC MOTOR:
A DC motor is designed to run on DC electric power. Two examples of
pure DC designs are Michael Faraday's homopolar motor (which is
uncommon), and the ball bearing motor, which is (so far) a novelty. By
far the most common DC motor types are the brushed and brushless
types, which use internal and external commutation respectively to
reverse the current in the windings in synchronism with rotation.
Neeraj Khatri Page 34 926/ECE/10
Most electric motors operate through the interaction of magnetic
fields and current-carrying conductors to generate force. The reverse process, producing electrical energy from mechanical energy, is done
by generators such as an alternator or a dynamo; some electric motors
can also be used as generators, for example, a traction motor on a vehicle may perform both tasks. Electric motors and generators are
commonly referred to as electric machines.
Electric motors are found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools,
and disk drives. They may be powered by direct current, e.g.,
a battery powered portable device or motor vehicle, or by alternating current from a central electrical distribution grid or inverter. The
smallest motors may be found in electric wristwatches. Medium-size
motors of highly standardized dimensions and characteristics provide convenient mechanical power for industrial uses. The very largest
electric motors are used for propulsion of ships, pipeline compressors,
and water pumps with ratings in the millions of watts. Electric motors may be classified by the source of electric power, by their internal
construction, by their application, or by the type of motion they give.
Features of 12v dc motor:
100RPM 12V DC motors with Gearbox
3000RPM base motor 6mm shaft diameter with internal hole
125gm weight
Same size motor available in various rpm 1.2kgcm torque
No-load current = 60 mA(Max), Load current = 300 mA(Max)
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AFTER ASSEMBLING MECHANICAL PARTS :
(Snapshot)
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SOFTWARE PART
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PROGRAM:
M1CW EQU P0.0
M1CCW EQU P0.1
M2CW EQU P0.2
M2CCW EQU P0.3
ORG 0000H
MAIN: MOV A,P2
CJNE A,#0F2H,NXT1
AJMP FWD
NXT1: CJNE A,#0F4H,NXT2
AJMP LFT
NXT2: CJNE A,#0F8H,NXT3
AJMP REW
NXT3: CJNE A,#0F6H,NXT4
AJMP RGT
NXT4: CJNE A,#0F5H,MAIN
AJMP STP
FWD: SETB M1CCW
SETB M2CCW
CLR M1CW
CLR M2CW
AJMP MAIN
REW: SETB M1CW
SETB M2CW
CLR M1CCW
CLR M2CCW
AJMP MAIN
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RGT: SETB M2CCW
SETB M1CW
CLR M2CW
CLR M1CCW
AJMP MAIN
LFT: SETB M2CW
SETB M1CCW
CLR M2CCW
CLR M1CW
AJMP MAIN
STP: MOV P0,#11111111B
AJMP MAIN
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SNAPSHOT
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CONCLUSION
I am very satisfied with the experience gained during this practical
training. I was given the possibility to work hand in hand with other Students inside the Institute learning about essentials of Embedded
System.
As a student of ELECTRONICS & COMM. ENGINEERING I tried to
learn somewhat concept of the Embedded System which is mainly concerned with my focus area.
In the technical aspect, we conclude that nothing can be understood
thoroughly without practical knowledge and practice. We observed
almost each process related to casting that we had just studied in books. It was really a fruitful training for us to enhance our knowledge and
confidence level.
At last, I would like to say thanks again all staff of the unit who helped
me through my training period.