A SMART HOME CONTROL AND MONITORING SYSTEM FOR THE DISABLED

A Smart Home Control and Monitoring System For The Disabled, Rishab Shah, Harish N.S, Dr.G.N.

Rathna, Journal Impact Factor (2015): 8.9958 (Calculated by GISI) www.jifactor.com

www.iaeme.com/ijecet.asp 26 [email protected]

1,2

Department of Electrical and Electronics Engineering,

Bangalore Institute of Technology, Bangalore, India

3Department 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).

Keywords: BCI, Arduino, Smart Home, SMS, Ethernet.

I. 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 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

A SMART HOME CONTROL AND MONITORING SYSTEM

FOR THE DISABLED

Rishab Shah1, Harish N.S

2, Dr.G.N. Rathna

3

Volume 6, Issue 6, June (2015), pp. 26-35

Article ID: 40120150606004

International Journal of Electronics and Communication

Engineering & Technology (IJECET)

© IAEME: http://www.iaeme.com/IJECET.asp

ISSN 0976 – 6464(Print)

ISSN 0976 – 6472(Online)

IJECET

© I A E M E




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.

II. IMPLEMENTATION

Fig. 1 Block Diagram (a) Control modes, (b) Home appliances

The Fig. 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.

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 [9]. 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.

III. CONTROL CIRCUITS

A. Relay Circuit

Fig. 2 Relay Circuit

The relay circuit shown in Fig. 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 1KΩ between the control source

i.e., microcontroller and the base, limits current into the base. To prevent false switching, a resistor

R1 of value 10KΩ 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.




B. TRIAC Circuit

Fig. 3 Phase Controlled AC wave

Fig. 4 Zero Crossing Detector

A zero crossing detector (ZCD) is shown in Fig. 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.

Fig. 5 TRIAC Circuit

The Arduino sends a signal as per the delay set according to the following equation:

The frequency here is 50Hz (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.




IV. EMOTIV EPOC HEADSET

Fig. 6 (a) Emotiv EPOC headset (b) Electrode points of Emotiv EPOC

The Emotiv System shown in Fig. 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 Fig. 6(b). It is

connected to the computer using a proprietary 2.4GHz 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.

Fig. 7 Emokey software




The Emokey software, shown in Fig. 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. Fig. 8 shows the flowchart of the working of the Emotiv EPOC headset.

Fig. 8 Flowchart for working of the Emotiv EPOC headset

V. 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. Fig. 9 gives the Flowchart for the

working of the GSM shield.

Fig. 9 Flowchart for the working of the GSM shield




VI. 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. The

flowchart for the working of the Ethernet shield is given in Fig. 10.

Fig. 10 Flowchart for the working of the Ethernet shield

Fig. 11 Webpage layout of the smart home




The buttons created in the web page, as shown in Fig. 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.

VII. 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 20ms 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.

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.

VIII. 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 [10]. Hence,

to reduce the effects of this error rate, we have integrated the BCI with SMS and HTTP based

commands.

IX. REFERNCES

1. R Corralejo, R. Horneroand D. Alvarez,. “A Domotic Control System using Brain-Computer

Interface (BCI)”, IWANN 2011, LNCS, 6691, part I, pp. 345-352, 2011.

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Electroencephalogram signals generated from eye movements”, Australasian Physical and

Engineering Sciences in Medicine, Accepted, December, 2012.

3. H. Nisar, H.C. Balasubramaniam, W.T. Lee, Q.W. Yeoh, A. Malik, K. Yeap, “Analysis of

real-time brain activity while controlling an animated 3D cube,” Journal of Neurology, June

2013. (Accepted)

4. J. J. Szafir, “Non Invasive BCI through EEG: An Exploration of the Utilization of

Electroencephalography to Create Thought-Based Brain- Computer Interfaces,” Boston

College. 2010.

5.




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A SMART HOME CONTROL AND MONITORING SYSTEM FOR THE DISABLED