31-01-2012, 04:55 PM
Development of a cell phone based remote control systeman effective switching system for controlling home and office appliances.
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INTRODUCTION
The aim of the proposed system is to develop a cost effective
solution that will provide controlling of home appliances
remotely and enable home security against intrusion in the
absence of homeowner. The system provides availability due
to development of a low cost system. The home appliances
control system with an affordable cost was thought to be built
that should be mobile providing remote access to the
appliances and allowing home security. Though devices
connected as home and office appliances consume electrical
power. These devices should be controlled as well as turn on
/off if required. Most of the times it was done manually.
SYSTEM DEVELOPMENT
In this system we developed the overall method in two way.
First one is that the targeted devices can be controlled by
sending DTMF [2] (dual tone multi frequency) sent by user
.Another way is that targeted devices can be controlled by
voice messages.
DFT In Quadrature Form[4]
In the DFT, both the sine and cosine waves are used. The two
types of wave are obviously related by 90 degree phase shift.
An analogously shifted square wave is needed for the DTMF
decoding too. The reason is that it's possible to end up with a
small sum-of-products even if the two waveforms have the
same frequency.
