AN EMBEDDED MOBILE HOME AUTOMATION SYSTEM
Chin E. Lin*, Chien-Liang Lin, Chih-Ching Li
Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan 701
Yin-Hua Zhou
School of e-Business, South China University of Technology, Guangzhou, China 510006
Keywords: Home automation, home security, mobile communication, RF communication, remote control.
Abstract: This paper proposes a home appliance automation system in design and realization. This system is
accomplished by embedded boards, radio frequency (RF) transceivers, microprocessors, switching circuits,
sensor circuits and GSM (Global System for Mobile Communication) modules. This system mainly consists
of two subsystems for home appliance control and home security monitor. In the home appliance control,
we combine RF and WAP (Wireless Application Protocol) technologies for controlling home appliances,
where RF is for home network and WAP is for remote interconnect to home network via mobile
communication. For all security concern or emergency occasion, a SMS (short message service) may
automatically be generated from the microprocessor and sent to assigned cell phone number. The proposed
system would not only offer personal mobility and life convenience, and also provide home security for
better living environment.
1 INTRODUCTION
Home automation brings the distinct advancements
of security, convenience and comfort for human life.
Home appliances can be connected to outside world
through network, no matter wireless or wired system
is adopted. Control and monitor to home
appliances remotely can be made from anywhere.
The trends of home automation can be divided into
two categories: one for home appliance control and
energy management, while the other for household
security and safety (Tan, 2002, Dewsbury, 2002).
Home network would be combined with mobile
network to realize dreams of intelligent home to
mobile phone to control remotely home appliances
(Nikolova, 2003). Home appliances will get smart
in the future with incorporating some functions of
sensor and control (Badami, 1998). Low power, low
cost, short-range wireless circuit architectures are
also equipped into those smart home appliances to
achieve the always-connected home network
(Tuttlebee, 2001). This is a novel originality to
improve the life quality and to realize smart home.
Nikolova utilized mobile terminal to control
home appliances (Nikolova, 2003). HAVI (Home
Audio Video interoperability) was applied in home
network, and WAP phone was remotely used to
interconnect home network via mobile network.
Tan also presented a similar architecture, using WAP
phone to control home appliances (Tan, 2002).
However, the Bluetooth wireless network technology
was used in the house to replace wired connection to
avoid disorderly household environment. By this
concept, Chen combined Internet with Radio to
implement home control system Chen, 2004) for
more delicate control implementations.
Relative to use personal computer as home
server, there is another choice for using embedded
board. Ramakrishnan presented an embedded web
server based on 16-bit microprocessor to implement
web-based data acquisition and control
(Ramakrishnan, 2004). Hartwig also presented a
concept of wireless micro-server by integration of
electronic devices (Hartwig, 2002). Some
applications were studied for tele-health and patient
monitoring at home for e-health applications.
WAP-based telemedicine system to monitor the
elderly persons in remote, or an Internet-based
in-house control and monitoring system were
interested in study. They combined home automation
and healthcare system for an aging society Hung,
2003).
Home network technology is available in three main
categories: Busline (Cebus, LonWorks, EIB, etc);
Powerline (EIB Powerline, X10, etc) and Radio
Frequency (WiFi-802.11, Bluetooth, Radio etc).
Radio frequency is main difference from Busline and
Powerline that no wires need to be connected to
home appliances. Maybe only one chip is used to be
ported to home appliances, and the
intercommunication between home appliances would
be implemented. A typical RF communication
65
E. Lin C., Lin C., Li C. and Zhou Y. (2006).
AN EMBEDDED MOBILE HOME AUTOMATION SYSTEM.
In Proceedings of the International Conference on Wireless Information Networks and Systems, pages 65-72
Copyright
c
SciTePress
includes a pair of transceiver with
encoding/decoding and modulation.
WAP is capable to show Internet contents on
wireless clients, like mobile phones (Education,
2000) and enables to create web applications for
mobile devices, based on Internet standards (HTML,
XML and TCP/IP). WAP is also adopted as a
boarder-free long distance communication and
remote control.
While GSM of 900 MHz and 1800 MHz is used
as voice communication channel frequencies in
TDMA/FDMA (Jorg 2001, Gunnar, 1998), its
stacked on GPRS can be used for always-on data
communication (Jochim, 2001, Christoffer, 2001).
GSM is mainly used for voice communication and
short message service (SMS). In Taiwan and China,
very high population of SMS is created. In this
paper, GSM SMS will be adopted for emergency
report to the user. The most difference between
GSM and GPRS is that GPRS improves the wireless
access to packet data network. So data
transmission rates of GPRS are faster than GSM
system. The always online feature is also an
advantage for GPRS Christoffer 2001). GPRS in
this paper is a means to transmit WAP message.
This paper proposes a feasible approach of home
automation by integrating Radio connection and
mobile communication. This system mainly consists
of two subsystems: home appliance control system
and emergency report system.
(1) Home appliance control system: A graphical
user interface (GUI) is displayed on the WAP
browser for our control operation while
connecting through mobile communication
(Gundavaram, 1996). Then, home users could
remotely use WAP phone to control home
appliance.
(2) Emergency report system: If some emergencies
occur in the house such as a conflagration or
temperature abnormality, the proposed
emergency report system would automatically
send SMS alerts to home users to prevent a
disaster through GSM.
This system combines radio connection in our
house with mobile communication around the world
to offer personal mobility and convenience into our
life. Moreover, it also provides security and prevents
disaster for our house. System design,
implementation and tests are presented.
2 THE PROPOSED HOME
APPLIANCE SYSTEM
In this paper, an embedded home automation system
is proposed. The proposed system architecture
mainly consists of two subsystems in developing
prototypes: (1) the home appliance control system;
(2) emergency report system, are shown in Figures 1
and 2.
Home users could use WAP phone to control
home appliance outside our house through the
proposed home appliance control system. If any
emergencies occur in the house such as a
conflagration or temperature abnormality, the
proposed emergency report system would
automatically send SMS alerts to home users to
prevent a disaster through GSM. It creates security
for our house.
2.1 Home Appliance Control System
The home appliance control architecture is shown in
Figure 3. The home user use mobile terminal (WAP
phone) to connect to the embedded web server
through wireless network. Then, a graphical user
interface (GUI) displays on the WAP browser for
our control operation. Choose a decided control to
home appliances and push a button to transmit
control information to the embedded server. After
the embedded web server receives the control
information from WAP phone, it would transform
the control information to the mapping 4-bit control
data. Then, the mapping 4-bit data would output to
RF module in order to communication with home
appliance controller. The home appliance controller
analyzes the received 4-bit data to control
corresponding home appliances. In the proposed
system, home user could transmit control data from
WAP phone to home appliance controller in order to
switch home appliance. Similarly, the
acknowledgement character could be transmitted
from home appliance controller to WAP phone in
order to response to home user that if this operation
is success
.
(a) The Embedded Web Server. The embedded
web server is implemented using NET-Start!
TM
embedded board. The NET-Start!
TM
is a compact
networking startup toolkit, based on a 32-bit
ARM7TDMI network processor - S3C4510. The
operating system called μClinux was ported to
the embedded board by WISCORE Inc. The
WAP phone can connect to the embedded web
server through wireless network. In addition, we
add extra RF transceiver module to this
embedded board in order to communication with
home appliance controller in our house. In fact,
we use this embedded board to play as
communication interface from WAP phone to
home appliance controller.
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66
Figure 1: Concept of the proposed home appliance control.
Figure 2: Concept of the emergency report.
Figure 3: The proposed home appliance control.
Figure 4: The proposed emergency report.
(b) Home Appliance Controller. The home
appliance controller consists of an AT89C51
microprocessor, a RF transceiver module and a
switching circuit. We choose AT89C51 to
handle communication and to give the
command of switching circuit to turn on/off
home appliances. The home appliance
controller receives 4-bit control data from the
embedded web server through radio by using
RF module. Then, AT89C51 would drive
switching circuit to control the home appliance,
which home users want to control, by gauging
this received 4-bit data.
2.2 The Emergency Report System
The architecture of the proposed emergency report
system is depicted in Figure 4. If temperature is
higher than normal value inside our house,
temperature sensor module would transmit 4-bit data
to the embedded server through radio by using
Tx-304 transmitter. When the embedded server
receives 4-bits data, it would send SMS to home user
by writing AT commands to GSM module. The
emergency report system provides security and
prevents disaster for our house. The proposed
emergency report system consists of temperature
sensor module and the embedded server.
(a) Temperature Sensor Module. The AD590 is a
AN EMBEDDED MOBILE HOME AUTOMATION SYSTEM
67
two-terminal integrated circuit temperature
transducer that produces an output current
proportion to absolute temperature. The output
current of sensor AD-590 would be converted to
voltage by passing a 5K precision resistor. The
AD-590 is used in sensor module to detect
temperature for home security.
(b) The Embedded GSM Server. The embedded
GSM server consists of a RX-304 receiver, the
embedded board and a GSM module. The
Rx-304 receiver could be connected with
temperature sensor module through radio.
Then, the embedded GSM server would send
message to home user’s cellular phone through
GSM on the occurrence of the disaster.
(c) 4-bit Data Corresponding Table. In proposed
home appliance control system, we transmit
4-bit data to control home appliances through
radio by using RF module. In proposed
emergency report system, we send message to
home user according to 4 bit data transmitted
from sensor module to the embedded server.
The 4-bit data are assigned to each different
mode of control.
2.3 The Circuit of RF Module
We transmit 4-bit control data through radio using
RF module as the wireless environment in house.
The RF module, includes a Tx-418 transmitter and
an Rx-304 receiver, as shown in Fig. 5, is added to
the embedded broad in order to communicate with
home appliance controller inside our house.
Frequency 418 is assigned to send from the
embedded server to the home appliance controller,
and vise versa for frequency 304. The RF module
is applied as the wireless interface in the proposed
system.
(a) Tx-304 Transmitter. The transmitter of RF
module includes a DIP switch, a encode IC
HT-12E and a transmitting circuit as shown in
Figure 4. For HT-12E, A1 to A8 are its
address codes that have 8-bit. We can use dip
switch or microprocessor to set it up. D1 to
D4 are data inputs of 4-bit. When we want to
transmit data, we must set an address code with
data together. The receiver can get data when
the address code of transmitter and that of
receiver are matched.
(b) Rx-304 Receiver. The receiver of RF module
includes a DIP switch, a decode IC HT-12D and
a receiving circuit as shown in Figure 5. A1 to
A8 is the address codes of HT-12D that are
compared with the address codes of HT-12E.
It will check three times repeatedly. If it is
correct, 4-bit data would be received through
Rx-304 receiver.
Figure 5: Tx-304/RX-304 transceiver.
2.4 Home Appliance Control
Application Software
The software interaction for home appliance control
system is depicted in Figure 6. It includes several
programs that are composed of WML program, the
embedded web server software suite, CGI program
and 8051 control program.
(1) The NET-Start!
TM
embedded board is used to be
as a embedded context server using the
micro-server program thttpd.
(2) Develop web page written in WML and CGI
program written in C language. Place them in
the embedded context server in order to be
accessed from mobile terminal.
(3) Utilize WAP phone as mobile terminal to access
web page to be displayed on the WAP browser.
The web page is designed for home user to
choose home appliance to control.
(4) The CGI program is used to form an
acknowledgment web page to user on the WAP
browser and to transmit control data to activate
home appliance controller through radio.
(5) When receiving the control data, 8051 control
program would turn the home appliance on/off.
At the same time, 8051 control program also
give an acknowledge response to embedded
server.
(6) We can choose appropriate appliance via the
software interaction.
(a) Web Page on WAP Browser Simulator. We
develop web page on WAP browser simulator
using WML language in order to control
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68
appliance remotely. We can download the
Nokia mobile internet toolkit (NMIT) to develop
our web page from Website
http://forum.nokia.com. We develop and edit
mobile-browsing content by using NMIT by
Nokia. Then, we preview WML language and
display it on simulate WAP phone, as shown in
Figure 8. The detail specifications can be
downloaded for NMIT user guide from Nokia
website.
(b) CGI Programming. CGI is common gateway
interface. The CGI standard was developed
jointly by CERN (the European Laboratory for
Particle Physics) and NCSA (the National Center
for Supercomputing Applications). The CGI
standard provides a consistent interface between
Web server and application programs that strong
their capability. In other words, the Web server
can call up a program through CGI, while
passing user-specific data to the program. CGI
is not a programming language or a protocol.
CGI is only an interface that enables software to
communication (Gundavaram, 1996). The CGI
program can be written by using C, Perl or Shell
script. In our paper, use C language to
implement the CGI program. The user gives
particular requests (information) from the
WWW browser to Web server. The Web
server shares this information with the CGI
program. This information is delivered by
using environment variables. When the CGI
program is implemented, we place the CGI
program in legal CGI path. Thus, we can
deliver data requested from WAP browser to the
CGI program through common gateway
interface. In our work, the CGI program is used
to do two things. First, the CGI program can
output control signal to control home appliance
through radio. Second, the CGI program
responses a new document to user in order to
check if action is success.
(C) Home Appliance Control Program. In the
program, we initialize some settings and wait for
a negative edge-trigger of VT to enter interrupt
sub-program. We receive 4-bit data from
embedded server through radio. Then we judge
4-bit data to turn on/off the corresponding home
appliance. If the action is success, we would
response 4-bit data to server to be as
acknowledgement code.
2.5 Emergency Report System
Application
The software interaction of emergency report system
includes a serial program to activate GSM module
connected to embedded board via RS-232, as shown
in Figure 7. While sensor module is activated due
to a disaster such as a conflagration or temperature
abnormality, SMS alerts would be sent to user’s
cellular phone by running serial program. Then,
this alert would be displayed on the cellular phone to
give home user a warning. Serial program edited
by c language is installed to communicate with GSM
module. First, we have to initial settings for
opening RS-232 port. Then, we activate GSM
module by writing AT command. Finally, we can
send short message to mobile phone using GSM
module.
Figure 6: Control interaction.
AN EMBEDDED MOBILE HOME AUTOMATION SYSTEM
69
Figure 7: Emergency report interaction.
3 IMPLEMENTATION AND TEST
The proposed embedded home appliance control and
security system design is presented. The system
hardware has been implemented on an embedded
board and microprocessor linking via RF modules
for two general functions of home appliance control
application and emergency report application.
System software interacts with hardware in an
integration performance for verification and tests.
3.1 Home Appliance Control
With home appliance control architecture, home user
can use mobile terminal (WAP phone) to control
home appliances, such as lamp shown in Figure 8, or
other home appliances. It refers to system
architecture as shown by Figure 3 and Figure 6.
After this operation is success, acknowledge
character by graphical user interface (GUI) is
displayed on the WAP browser for our control
operation, as shown in Figure 9(a).
Acknowledgement is a necessary characteristic to
ensure a successful operation.
(a) (b)
Figure 8: Lamp control.
(a) (b)
Figure 9: SMS emergency report.
3.2 Emergency Report System
While an abnormal condition occurs at home
appliance, an emergency report will be sent to the
home user by SMS alerts through GSM as shown in
Figure 9(b), referring to Figure 4 and Figure 7 for
operation. Sensors where are necessary should be
installed for monitoring. The received SMS alerts
would be displayed on user’s mobile phone as a
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70
warning to home user.
4 CONCLUSION
The proposed system is designed and realized
successfully with full function tests. The system
can not only control remotely home appliance but
also protect home security. The proposed system
provides a network-based approach to make it
possible by combining RF and mobile
communication, that personal mobility is very much
appreciated. It has been verified to offer personal
mobility and security into domestic life, and to fulfill
the ideal home automation system into real world.
Modern and developed countries, people might need
to work for 9-5, their home situation might be a
significant concern to most people. Home
automation as well as security awareness may offer a
fulfillment to those expectations in highly mobility
performance. In this paper, we present a feasible
solution of home automation by integrating the
Internet, RF communication and mobile
communication into an operational system. The
proposed system can not only be a part of home
appliance remote control system using WAP phone,
but also be a part of home security report system for
household emergency to the users through SMS on
cell phone. The performance has been verified in
good condition to match the design requirements.
Based on the proposed system, the main
objectives have been achieved as summarized. (1)
The proposed system provides the network-based
solution of the network accessibility and network
acquisition. (2) It combines RF home network with
mobile communication to offer personal mobility
and convenience for home users. (3) RF home
network technology is used to replace traditional
wired connection to avoid disorderly household
environment or wasting space. (4) The embedded
board is used to replace traditional personal
computer to be as a home server for saving
household space. (5) This system improves the
home security of household environment due to the
emergency report mechanism. (6) The overall
system performance increases the residence quality,
comfort and convenience of home life.
In this paper, some shortages and problems
should be mentioned. (1) The time of establishing
a connection to the server requires about 7 to 9
seconds, and after connecting to the server, the time
required for dynamic generation of WML is about 1
to 3 seconds in average. This problem might be
improved 3G (third-generation) or B3G (beyond 3G)
system. The emerging 3G or B3G mobile
communication would promote a much higher data
rate, and newer versions of WAP specifications
would promote stability. (2) EMI (Electromagnetic
Interference) presents a serious influence on RF
transceiver module that devalues the effective
distance and its stability. Higher frequency RF
module or message protocol may improve this
problem. New wireless technologies, such as
Bluetooth or WiFi-802.11, could be applied. The
advantages of these emerging technologies are
higher data rates, longer transmitting distance and
excellent stability. It should be a feasible solution
by integrating emerging wireless technologies into
home automation in the future.
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