GSM based Home Automation Name : Rajneesh Salgotra EnRol : 163/2010 Roll : 31 1
Nov 18, 2014
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GSM based Home Automation
Name : Rajneesh Salgotra EnRol : 163/2010
Roll : 31
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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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