Ijecet 06 06_004

http://www.iaeme.com/IJECET/index.asp 29 editor@iaeme.com
International Journal of Electronics and Communication Engineering & Technology
(IJECET)
Volume 6, Issue 6, Jun 2015, pp. 29-38, Article ID: IJECET_06_06_004
Available online at
http://www.iaeme.com/IJECETissues.asp?JTypeIJECET&VType=6&IType=6
ISSN Print: 0976-6464 and ISSN Online: 0976-6472
© IAEME Publication
___________________________________________________________________________
A SMART HOME CONTROL AND
MONITORING SYSTEM FOR THE
DISABLED
Rishab Shah and N. S. Harish
Department of Electrical and Electronics Engineering,
Bangalore Institute of Technology, Bangalore, India
Dr. G. N. Rathna
Department of Electrical Engineering, Indian Institute of Science,
Bangalore, India
ABSTRACT
The recent advancements in the field of embedded systems enables us to
develop a reliable smart home system for easier access to home appliances.
The aim is to provide a seamless integration of various methods of controlling
appliances in the smart home aiding the physically challenged. This can be
done by means of a non-invasive Brain-Computer Interface (BCI), text
messaging and a personalized web page. This paper proposes a novel method
wherein the physically challenged people can control the appliances by using
Emotiv EPOC headset which reads the Electroencephalographic (EEG)
signals recorded from the brain activity and communicates with an Arduino
board. The proposed system has been built with the help of an Ethernet shield
which runs a webserver, and a GSM shield which communicates with the
Arduino through text messaging (SMS).
Key words: BCI, Arduino, Smart Home, SMS and Ethernet.
Cite this Article: Shah, R., Harish, N. S. and Dr. Rathna, G. N. A Smart
Home Control and Monitoring System for the Disabled. International Journal
of Electronics and Communication Engineering & Technology, 6(6), 2015, pp.
29-38.
http://www.iaeme.com/IJECET/issues.asp?JTypeIJECET&VType=6&IType=6
_____________________________________________________________________
1. INTRODUCTION
A smart home, or smart house, is a home that incorporates advanced automation
systems to provide the inhabitants with sophisticated monitoring and control over the

Rishab Shah, N. S. Harish and Dr. G. N. Rathna
building's functions. Another name popularly given to this concept is home
automation.
This paper is focused on helping quadriplegics, pregnant women or the elderly
maintain independence and safety in the comfort of their homes. This form of home
automation is called assistive domotics. This is achieved by using a non-invasive BCI
system [1], SMS and Ethernet. The disabled can communicate with able-bodied
people using the BCI system to send an emergency SMS. The BCI technology is
developing very rapidly, as it has innumerable uses [2]-[4], the most important of
which is improving the quality of life of the elderly and physically challenged. The
other two modes of control are used as contingencies to the BCI system so that an
able-bodied person can monitor and control the home appliances. This project enables
the user to toggle lights, other similar appliances and also control the speed of fans.
To achieve this, the concept of EEG has been used to record electrical activity of the
brain along the scalp. EEG measures voltage fluctuations resulting from ionic current
flows within the neurons of the brain. The BCI system used in this paper is the
Emotiv EPOC [5] headset. An Arduino [6] board has been used as the microcontroller
to control the electrical appliances. The Arduino Integrated Development
Environment (IDE) [6] has been used to program the microcontroller. The Arduino
GSM Shield [7] allows an Arduino board to send/receive SMS messages. The
Arduino Ethernet Shield [8] allows an Arduino board to connect to the internet.
2. IMPLEMENTATION
Figure 1 Block Diagram (a) Control modes, (b) Home appliances
The Figure 1 shows the main structure of the system. In this network, the Arduino
situated at the centre operates as the brain of the system. The Arduino takes the input
from Emotiv EPOC, Ethernet Shield and the GSM Shield and processes it to send the
signal to the load circuit.
The loads such as Electrical appliances are connected to the Arduino through the
relay circuits. These relays are used to switch the loads ON or OFF. The inductive
load uses the TRIAC circuit. The Arduino controls the complete load circuit. These
loads can be manually overridden when necessary.

A Smart Home Control and Monitoring System for the Disabled
To send the input to the Arduino, components such as network tower and
Smartphones can be used. However these components are already accessible to any
common man, so the burden is to link it to the Arduino. This can be done by using the
GSM Shield. The GSM Shield requires a SIM card to operate. The input is sent to the
Arduino through the GSM Shield in the form of SMS. The process is similar to
sending a simple message to anyone. To do this, the user must know the SIM contact
number. Once the SIM contact number is known, the SMS is sent to the SIM card
inserted in the GSM Shield. The GSM Shield processes the received SMS by
searching for the predefined variable.
The other method to access the Arduino is through the Ethernet Shield. Basically,
this is as simple as surfing the internet. A smartphone with internet access or a
computer with internet connectivity is the only requirement. The Ethernet shield hosts
the webserver for this purpose. A web page is created and hosted through the server to
achieve this. Through this web page, the input is given to the server by pressing the
appropriate buttons shown on the screen. By pressing these buttons, the signals is sent
to the server. The Ethernet Shield processes the input signal and notifies the Arduino
to toggle the load.
Most importantly, without the help of smartphones or internet, the Arduino can be
accessed just with the help of the neural signals. This serves the disabled who cannot
access the home appliances by any other means. This method requires an Emotiv
EPOC headset to access the Arduino [11]. This head gear uses EEG signals. After
suitable training, the system stores the signal which can then be used repeatedly.
Whenever the signal input is given, the system compares the signal with previously
stored signals and after the comparison, the system recognises the operation to be
carried out. This method is different in terms of operation compared to other two
methods. The Emotiv EPOC headset requires a computer to process and compare the
signal before it is fed to the Arduino.
3. CONTROL CIRCUITS
3.1. Relay Circuit
Figure 2 Relay Circuit

The relay circuit shown in Figure 2 is used for switching ON/OFF any appliances up
to the rated value of the relay. The main components of the circuit are the NPN transistor
2N3904 and the relay. The most fundamental application of a transistor is to control the
flow of power to another part of the circuit by using it as a switch. The series resistor R2
of value 1 KΩ between the control source i.e., microcontroller and the base, limits
current into the base. To prevent false switching, a resistor R1 of value 10 KΩ is used.
A zener diode has been used as a shunt regulator to regulate the voltage across small
circuits and when connected in parallel with a variable voltage source, so that it is reverse
biased, a zener diode conducts when the voltage reaches the diode's reverse breakdown
voltage. From that point on, the relatively low impedance of the diode keeps the voltage
across the diode at that value. It also serves the purpose of a freewheeling diode.
A relay has been used to control a circuit by a low-power signal (with complete
electrical isolation between control and controlled circuits). The Light Emitting Diode
(LED) is used for de-bugging and the R4 resistor acts as a current limiting resistor.
3.2. TRIAC Circuit
Figure 3 Phase Controlled AC wave
Figure 4 Zero Crossing Detector

A zero crossing detector (ZCD) is shown in Figure 4 and it is H11AA11 is used
for detecting or monitoring AC signals. It provides AC Line/Digital Logic Isolation. It
is a 6-PIN Dual In-Line Package (DIP) opto-isolator AC Input/Transistor output.
When the AC signal crosses zero point, the zero crossing detector senses this and
sends a signal to the Arduino, the Arduino interrupts the program and navigates to
Interrupt Service Routine (ISR) which determines the delay to be introduced in the
output waveform.
Figure 5 TRIAC Circuit
The Arduino sends a signal as per the delay set according to the following
equation:
The frequency here is 50 Hz (that of the AC mains). The number of steps implies
the smoothness of the AC wave by sampling the input waveform. In this case, we
have used 128 step sampling. This means that one half cycle is divided into 128 steps.
Substituting these values in the above equation, we get a delay of 78 μs/step. This is
the optimal value without introducing a phase shift in the output waveform. In order
to vary the speed of the single phase induction motors (fans), this frequency step
should be changed. A lower frequency step indicates a higher speed and vice versa.
This varying output is fed to the opto-isolator. MOC3020M is a 6-Pin DIP
Random-Phase Optoisolators TRIAC Driver Output. The MOC3020M is optically
isolated TRIAC driver devices. Based on these waveforms the opto-isolator activates
the gate terminal of the TRIAC.
Unwanted turn-ons are avoided by using a snubber circuit between MT1 and
MT2. Snubber circuit has been used to prevent premature triggering, caused by
voltage spikes in the mains supply. Because turn-ons are caused by internal capacitive
currents flowing into the gate as a consequence of a high voltage dv/dt, (i.e., rapid
voltage change) a gate resistor has been connected between the gate and MT1 to
provide a low-impedance path to MT1 and further prevent false triggering. This,
however, increases the required trigger current or adds latency due to capacitor

charging. On the other hand, a resistor between the gate and MT1 helps draw leakage
currents out of the device, thus improving the performance of the TRIAC at high
temperature, where the maximum allowed dv/dt is lower. The LED and a current
limiting resistor in series is used for de-bugging.
4. EMOTIV EPOC HEADSET
Figure 6 (a) Emotiv EPOC headset (b) Electrode points of Emotiv EPOC
The Emotiv System shown in Figure 6(a) is an electronics company developing
brain–computer interfaces based on EEG technology. The Emotiv EPOC headset is a
BCI and Scientific Contextual EEG offering high resolution, 14 EEG electrodes and 2
reference electrodes, shown in Figure 6(b). It is connected to the computer using a
proprietary 2.4 GHz Bluetooth 4.0 connection.
The Emotiv control panel lets the user setup the electrodes for optimal signal
reception. It also contains 3 suites, viz the Expressiv suite, the Affectiv suite and the
Cognitiv suite. The Expressiv suite and the Cognitiv suite enables us to train the SDK
for 8 seconds, so that it can recognize our actions more accurately. The control panel
can store profiles of multiple users, so that there is no need to train the software every
time. The Emotiv control panel enables us to set up the headset so that optimum
signal to noise ratio is obtained. This ensures that the background noises are
eliminated. The signals received by the electrodes are transmitted via Bluetooth to the
computer running the Emotiv control panel. These signals are then forwarded to the
Emokey, where a number of actions and their corresponding keystrokes and threshold
values are defined.
Once the setup is done, the user selects a target software for the Emokey to send
these signals. In this case, it is the Arduino software serial monitor. The code written
for this project constantly checks the serial buffer for any received variable. If a
variable is received and it matches with the variables assigned in the Arduino code,
the Arduino performs the particular action.
In emergency, the Emotiv EPOC headset is programmed to send a Short
Messaging Service (SMS) defined by a particular action to a predefined contact
number.

Figure 7 Emokey software
The Emokey software, shown in Figure 7, acts as a bridging software to connect
the Emotiv control panel to the Arduino. It is used to assign variables to the user
actions received from the control panel. The Emokey software lets the user assign any
character on the standard keyboard to a particular action. Figure 8 shows the
flowchart of the working of the Emotiv EPOC headset.
Figure 8 Flowchart for working of the Emotiv EPOC headset
5. GSM SHIELD
A Shield is a peripheral device which allows the Arduino microcontroller to perform
specific functions. The GSM shield uses a radio modem M10 by Quectel. Figure 9
gives the Flowchart for the working of the GSM shield.

Figure 9 Flowchart for the working of the GSM shield
6. ETHERNET SHIELD
In this project, the focus is on using the Arduino Ethernet Shield to create a webserver
and run a web page on it. This web page is configured to control the appliances in the
smart home [9]. The flowchart for the working of the Ethernet shield is given in
Figure 10.
Figure 10 Flowchart for the working of the Ethernet shield

Figure 11 Webpage layout of the smart home
The buttons created in the web page, as shown in Figure 11, are linked to the
operation of home appliances through the Arduino code, which then checks
repeatedly for any button clicks. If a particular button is clicked, the corresponding
command is given from the Arduino to the port, which in turn performs the action
desired (say, turn on a particular light). These buttons are programmed with toggling
action to make the User Interface (UI) simpler and clearer.
To access the web page in the browser, the user has to be connected to the same
network in which the server is run. The IP address used earlier to run the server on
acts as the Uniform Resource Locator (URL) for the web page. The access to the web
page can be made public by creating a HTTP server and opening its port.
7. REASON FOR USING TWO MICROCONTROLLERS
There are two devices which uses the interrupts during the process, they are GSM
shield and ZCD. The GSM shield continuously searches for the input. To conduct the
search for an input, specifically SMS in case of GSM shield, the GSM shield requires
an interrupt. The GSM shield interrupts the program at every 20 ms as predefined in
the library to check for any incoming SMSs. The interrupt used in this case is a
software interrupt. Whenever the SMS is received, the interrupt stops the main
Arduino program to save the received SMS [10].
Similarly, the ZCD needs an interrupt to send the signal whenever the zero-
crossing is observed. The ZCD uses a hardware interrupt. The time gap between each
zero-crossing and GSM search interval may be same. But when the input is received,
it may alter the search interval. Due to this the ZCD and the GSM Shield sometimes
may need to use the interrupt simultaneously. Microcontroller is incapable of
interrupting a program to execute two different functions at the same time. In such
situations the microcontroller prioritizes the function which may induce some delay in
execution of other function. For this purpose, both the signals have to be dealt
separately. This is possible by using two separate microcontrollers to execute the
interrupts.

8. CONCLUSION
This paper proposes a method to assist the physically challenged, people suffering
from quadriplegia, pregnant women, elderly citizens suffering from diseases like
arthritis, etc. The accuracy of the headset is around 80%. This means that there is still
a 10–20% error rate [12]. Hence, to reduce the effects of this error rate, we have
integrated the BCI with SMS and HTTP based commands.
REFERNCES
[1] Corralejo, R., Horneroand, R. and Alvarez, D. A Domotic Control System using
Brain-Computer Interface (BCI), IWANN 2011, LNCS, 6691, part I, 2011, pp.
345–352.
[2] Nisar, H., Yap, V. V., Yeap, K. H. and Malik, A. S. Analysis of
Electroencephalogram signals generated from eye movements. Australasian
Physical and Engineering Sciences in Medicine, Accepted, December, 2012.
[3] Nisar, H., Balasubramaniam, H. C., Lee, W. T., Yeoh, Q. W., Malik, A. and
Yeap, K. Analysis of real-time brain activity while controlling an animated 3D
cube. Journal of Neurology, June 2013.
[4] Szafir, J. J. Non Invasive BCI through EEG: An Exploration of the Utilization of
Electroencephalography to Create Thought-Based Brain-Computer Interfaces,
Boston College, 2010.
[5] Emotiv.com EPOC Features, 2013. Retrieved from
http://www.emotiv.com/epoc/.
[6] Arduino. 2005. Retrieved from http://www.arduino.cc/
[7] Arduino GSM Shield, 2014. Retrieved from
http://www.arduino.cc/en/Main/ArduinoGSMShield
[8] Arduino Ethernet Shield, 2014. Retrieved from
http://www.arduino.cc/en/Main/ArduinoEthernetShield
[9] Kavitha, R., Dr. Nasira, G. M. and Dr. Nachamai, N. Smart Home Systems
Using Wireless Sensor Network – A Comparative Analysis. International
Journal of Computer Engineering & Technology, 3(3), 2012, pp. 94–103.
[10] Sucheendran, D., Asst Prof. Arun, R., Dr. Sasidhar Babu, S. and Prof. Jayakumar,
P. Securedsms: A Protocol For SMS Security. International Journal of Computer
Engineering & Technology, 5(12), 2014, pp. 37–41.
[11] Vourvopoulos, A. and Liarokapis, F. Brain-controlled NXT Robot: Tele-
operating a robot through brain electrical activity. Third International Conference
on Games and Virtual Worlds for Serious Applications, Coventry University,
Coventry, UK. 2011.
[12] Cho, H. -S. et. al, The Virtual Reality Brain Computer Interface System for
Ubiquitous Home Control, LNAI 4304, 2006, pp. 992–996.

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