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

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

 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!

embedded board. The NET-Start!

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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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

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.

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!

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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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.

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

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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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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