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GSM based Home Automation

Name : Rajneesh Salgotra EnRol : 163/2010

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GSM DTMF DTMF DECODER MICROCONTROLLER RELAYS COMPLETE CIRCUIT

Contents

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Now a days , GSM services easily available to everyone .

And You need not to carry a different remote controller .

Mobile Stations are already a multipurpose devices , so why not to incorporate one more

GSM (Global System for Mobile Communcation)

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Dual-tone multi-frequency signalling (DTMF) is used for telecommunication signalling

Between telephone handsets and other communications devices and the switching centre .

Double Tone Multi-Frequency

1209 Hz 1336 Hz 1477 Hz

697 Hz 1 2 3770 Hz 4 5 6852 Hz 7 8 9941 Hz * 0 #

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Continued ….

1209 Hz 1336 Hz 1477 Hz

697 Hz 1 2 3

770 Hz 4 5 6

852 Hz 7 8 9

941 Hz * 0 #

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Continued….

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DTMF DECODER

OUTPUT

INPUT

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FREQUENCY TABLE

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We have the decoded Hexadecimal Number corresponding to the pressed key

What NEXT ?

NOW Microcontroller to take Decision .

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MIRO

CONTROLLER

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Problem :

The output of Microcontroller is of very low power highly insufficient to operate electrical loads .

So we use relays for controlling electrical

heavy loads through Microcontrollers .

How to connect Devices ?

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Relay

AC POWER

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So Complete Circuit . . . .

+Vcc

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Remote controlled ROBOTS and APPLICANCES

Applications

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No feedback

GSM connection for the operation

Disadvantages :

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http://pdf1.alldatasheet.com/datasheet-pdf/view/77085/MITEL/MT8870.html

Mazidi, Muhammad Ali, The 8051 Microcontroller and Embedded Systems

SOLID STATE RELAY HAND BOOK http://chipscity.com/downloads/Projects/GSM%20based%20

Control%20System.pdf www.wikipedia.com 8051 MICROCONTROLLERS by SATISH SHAH

REFERENCES

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