15-03-2011, 08:18 PM
Wireless Home Automation Network
Sreevas. S
S6, Applied Electonics
College of Engineering, Trivandrum
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Abstract
Wireless home automation networks (WHAN) comprise of wireless embedded sensors and actuators that
enable monitoring and control applications for home user comfort and efficient home management.
Need:
In recent years, the number of devices that
need to be connected and controlled
remotely in an industrial and home
environment are several. In smart homes or
businesses there is a need to control these
devices remotely and power friendly
manner. WHAN is the solution to these
requirements.
Gsm Based Home Automation:
GSM (Global System for Mobile
Communications: originally from Groupe
Spécial Mobile) is the world's most popular
standard for mobile telephony systems
.When you press a DTMF key in the
telephone set keypad, a connection is made
that generates a resultant signal of two tones
at the same time. These two tones are taken
from a row frequency and a column
frequency. The resultant frequency signal is
called “Dual Tone Multiple Frequency”.
These tones are identical and unique.
A DTMF signal is the algebraic sum of two
different audio frequencies, and can be
expressed as follows:
f(t) = A0sin(2*_*fa*t) + B0sin(2*_*fb*t) +
……….. ——-> (1)
Where fa and fb are two different audio
frequencies with A and B as their peak
amplitudes and f as the resultant DTMF
signal. fa belongs to the low frequency
group and fb belongs to the high frequency
group.
Each of the low and high frequency groups
comprise four frequencies from the various
keys present on the telephone keypad; two
different frequencies, one from the high
frequency group and another from the low
frequency group are used to produce a
DTMF signal to represent the pressed key.
The amplitudes of the two sine waves
should be such that
(0.7 < (A/B) < 0.9)V ——–> (2)
The frequencies are chosen such that they
are not the harmonics of each other. The
frequencies associated with various keys on
the keypad are shown in figure (A).
When you send these DTMF signals to the
telephone exchange through cables, the
servers in the telephone exchange identifies
these signals and makes the connection to
the person you are calling.
Figure (B): A Typical frequency DTMF
signal
Along with these DTMF generator in our
telephone set provides a set of special
purpose groups of tones, which is normally
not used in our keypad. These tones are
identified as ‘A’, ‘B’, ‘C’, ‘D’. These
frequencies have the same column
frequency but uses row frequencies given in
the table in figure (A). These tones are used
for communication signaling.
Figure ©: The frequency table
Due to its accuracy and uniqueness, these
DTMF signals are used in controlling
systems using telephones. By using some
DTMF generating IC’s (UM91214,
UM91214, etc) we can generate DTMF
tones without depending on the telephone
set.
Main Features:
• Light control.
• Remote control.
• Smart energy.
• Remote care.
• Security and safety.
Technologies:
• Bluetooth— Used in PANs. Range is
~10m. ISM band at 2.4 GHz is
employed. Supports only Star
topology.
• Infrared (IR)—LOS operation,
limited range.
• ZigBee— Supports Star, Mesh, and
Tree topologies. Multihop
communication with unlimited
range.
• Radio Frequency (RF)— 413 MHz
or 315 MHz, Range ~100m.
Supports only Star topology.
Conclusion:
The much dreamt of concept of E-home can
be realized through this project. Speech
Controlled Interactive Wireless Home
Automation can be made realistic. The
immediate future will see a lot of rapid
strides made in this area.
Bibliography:
1. Baris Yuksekkaya, A. et.al., “A
GSM, Internet and Speech
Controlled Wireless Interactive
Home Automation System”, IEEE
Transactions on Consumer
Electronics, Vol. 52, No. 3,
AUGUST2006
2. Yu-Ping Tsou, et.al., “Building a
Remote Supervisory Control
Network System for Smart Home
Applications”, Proceedings of 2006
IEEE International Conference on
Systems, Man, and Cybernetics,
October 8-11, 2006, Taipei, Taiwan
3. Mohd Adib B., et.al., “Wireless
Home Security and Automation
System Utilizing ZigBee based
Multi-hop Communication”,
Proceedings of IEEE 2008 6th
National Conference on
Telecommunication Technologies
and IEEE 2008 2nd Malaysia
Conference on Photonics, 26-27
August 2008, Putrajaya, Malaysia.
