This document discusses a remote control system that uses DTMF tones sent over telephone lines to control electrical devices remotely. The system uses a DTMF decoder to convert the tones from a cell phone into digital commands that are sent to a microcontroller. The microcontroller then controls relays connected to various electrical loads, allowing them to be turned on or off from the phone. This remote control system could be useful for controlling agricultural pumps, industrial equipment, or household devices over large areas without needing to be near the equipment.

3. In the present world of wireless technology every thing is
going to be digital and wireless, and the cell phone is the key player
in wireless technology today. And today technology made the
possessing of a mobile, considered as a basic commodity.
And the trends in wireless technology changing day-by-day
and today the working is going on how to develop remote devices
with out the presence of man and to reduce to the time factor and
labor, and our project belongs to that race and by using it we can
control any electronic devices through a touch cell phone, with one
Call.

4. The main objective of this DTMF BASED
REMOTE CONTROL SYSTEM project is to develop an
embedded system which can control remote appliances
remotely by using telephone line. In this embedded
System Project we are going to develop an embedded
system which will control the remote appliances with the
telephone lines. We can control more than 10 electrical
Appliances.
First of all the telephone lines of data are
transmitting through the transmitter by the encoder, it
will encode the data without noise, and then the data will
be received at the receiver, so that the receiving data is
decode as original data of telephone line by the
decoder, then the original data is stored in
microcontroller and it will control the all the electrical
system.

10. The project works on the principle of DTMF tone command so
received from any phone to remotely switch any electrical load such as
agricultural pump, domestic and industrial loads etc. In industries, the
loads are spread over a large area and thus, operating these loads is a
very tiresome and difficult task. In agricultural fields also, pumps and
other loads are connected over a large area and hence it is difficult for the
farmer to operate all the loads and similarly for house hold loads.
Keeping these problems in mind, the proposed system has
been designed which uses DTMF technology to control the loads
remotely. A cell phone is interfaced to a DTMF decoder in the system
from its audio output socket for receiving tone commands.

11. The receiving cell phone codes are converted into digital
commands by using a DTMF Decoder which will identify the frequency
of the key and convert that frequency to its equivalent digital code
which is then fed to a microcontroller (8051 family).
As per the commands sent from the sender’s mobile, the
microcontroller will send signals through a buffer to actuate the
respective loads by turning the relays ON/OFF. These relays are
actuated by a relay driver IC interfaced to the microcontroller. Further
this project can be enhanced by using a GSM modem, where the loads
can be controlled by sending an SMS. This will eliminate the need of
answering the call for the system to work.

17. Go Green….