PPT of DTMF

7/30/2019 PPT of DTMF

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Presented ByJadhav Rohini B.

Jadhav Yojana A.

Sonawane Swati V.

Guided By

Prof.Dabhade R.G.


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Introduction Aim of the project is to design an automated system that can be

used to control devices in the event that one is not present to

control device manually.

The controller unit continually monitors your mobile and looks

for the proper user touch tone sequences to remotely control

devices around your home or office.

Once it is heard the controller unit then detects which switch

has been pressed and then according turns ON/OFF the

corresponding relay.


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Basics Of DTMFDTMF is an acronym for Dual Tone Multi-Frequency

signaling.

It is a signal that is to the switching center when the phones

keys are pressed.

DTMF is also called as Multi-Frequency Signaling because for

each key you press two tones of specific frequencies are

generated.

The DTMF controller offers full control from any

telephone anywhere in the world.


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A DTMF signal is the algebraic sum of two

different audio frequencies.

A number of companies make chips whichdecode these DTMF signal one such IC is MT 8870.

1209 Hz 1336 Hz 1477 Hz

697 Hz 1 2 3

770 Hz 4 5 6852 Hz 7 8 9

941 Hz * 0 #


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Features of DTMF decoderComplete DTMF Receiver

Low power consumption(35mw)

Power-down mode (5mw)Single 5 Volt power supply

Inhibit mode

Dial tone suppression

Central Office Quality & Performance


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MOBILE USED AS REMOTE

RELAY 1

7 SEGMENT DISPLAY

MICROCONTROLLER

AT89S52

RELAY

DRIVER

ULN2803

DTMF

DOCODER

230V POWER LINE

RELAY 5

RELAY 3

RELAY 4

RELAY 6

RELAY 2

RELAY 7

RELAY 8

APPLIANCE 1

APPLIANCE 2

APPLIANCE 8

APPLIANCE 7

APPLIANCE 6

APPLIANCE 5

APPLIANCE 4

APPLIANCE 3

POWER SUPPLY


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Circuit Diagram


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Circuit Diagram Description

Microcontroller

Small computer on a single integrated circuit containing a processorcore,memory & programmable I\O peripheral.

The 89S52 is low-power,high-performance CMOS 8-bit Microcontrollerwith Flash programmable & erasable ROM.

Controller executes instruction as per the clock cycles.

A power ON reset circuit is connected to the RESET pin of theMicrocontroller.

External Pull Up resisters on port 0.


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Features Of Microcontroller256 x 8-Bit internal RAM

32 Programmable I/O lines

Two 16-Bit Timer/Counters

Six Interrupt Sources

8K Bytes of In-system Reprogrammable Flash Memory

Fully static operation: 0Hz to 24MHz

Low power Idle & Power Down Modes

Compatible with MCS-51 Products


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Relay Relays are devices which allow low power circuits to switch a

relatively high Current|Voltage ON|OFF.

12V relay used here with which we can switch 5A load current.

Relays basically consists of five terminals.

Relay Driver To provide the necessary current & at the required voltage a

relay driver circuit is required.

We are using ULN2003 relay driver.


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Seven Segment Display

It is a form of electonic display device for displaying decimalnumbers.

To display the Number pressed by caller to control device.

They are used in digital clocks,electronic meters for displaying

numerical information.

DTMF Decoder

In the course of call if any button is pressed a tone correspondingto the button is heard at the other end of call.

Received tone is processed by the the microcontroller withDTMF decoder.

decoder decodes DTMF tone into its binary digit & send to theMicrocontroller.


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Power Supply

It is supply of elecrical power.

We require 5V for Microcontroller , LCD, EPROM & 12V for

the Relay.

These voltages are generated from 230V line vtg.

Step Down

Transformer

Transformer

Voltage

RegulatorFilter

Capacitor

Rectifier230V ACRegulated

Voltage


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AdvantagesPower saving

Best suitable for Bed-ridden patients

Easy operation

Convenient

Simple

Low cost

Can be operated from anywhere in the world.


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Disadvantages1We can not use screen touch mobile as

remote

2 We should not keep the all applications ONat a time of circuit performance


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ApplicationsThe DTMF based device control is a very useful project

with many applications in home or office switching

applications.

In Industries,where a large number or group of electrical

appliances are to be controlled,this device is much useful.

Hotels,Hospitals,Shops,banks &Offices.

Can be used in farming to turn ON/OFF motor & pumps.


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ReferencesText Books

Ayala-The 8051 Microcontroller

Mazidi-The 8051 Microcontroller

Website

www.dnatechindia.com

www.datasheet.com

Magazines

Electonics For You
http://www.dnatechindia.com/http://www.datasheet.com/http://www.datasheet.com/http://www.dnatechindia.com/


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THANK YOU!

PPT of DTMF

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