12 Kailash Pati Dutta 863 Research Article EEC August 2012

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Available ONLINE www.vsrdjournals.com

VSRD-IJEECE, Vol. 2 (8), 2012, 642-649

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1Research Scholar, 2Head of Department, 1,2Department of Electrical Engineering, BIT Sindri, Dhanbad, Jharkhand, INDIA.3Assistant Professor, Department of Electrical Engineering, Hindu College of Engineering, Sonipat, Haryana, INDIA.

*Correspondence : [email protected]

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Microcontroller Based Voice Activated

Wireless Automation System1Kailash Pati Dutta*,

2Pankaj Rai and

3Vineet Shekher

ABSTRACT

This paper presents the proposal, design and implementation of a microcontroller based voice activated wireless

automation system. As speech is the preferred mode of operation for human being, this project intends to make

the voice oriented command words for controlling home appliances. In this project, one voice recognition

module has been added to the wireless network. The automation centers at recognition of voice commands and

uses the Radio Frequency (RF) technology. The voice command is a person independent. The system comprises

of transmitting section and receiving section. Initially, the voice command is stored in the data base with the

help of the function keys. Then the input voice commands are transmitted through wireless. The voice received

is processed in the voice recognition system where the feature of the voice command is extracted and matched

with the existing sample in the database. The module recognizes the voice and sends control messages to the

microcontroller. The programmed microcontroller then processes the received data and switches the respective

appliances via connected driver circuits.

Keywords : RF, Voice Recognition Module, Micro Controller, motor, Relay.

1. INTRODUCTIONOver the past decade, technology has dramatically changed our life and living styles. The internet has made it

possible for people to connect to the world without stepping out of the house and wireless communication[1]

has

given people the convenience of keeping in touch with each other anytime anywhere. The design of new future

house[11]

is full of advanced tec hnol og ies . These new technologies offer homeowners a more comfortable

home environment doing automation which refers to any process that gives remote or automatic control of home

devices and appliances. The challenge to design better automation products is to accommodate the variation

among different users[6]. Also, a better user interface design can be the solution to some existing automation


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design problems[12]

. The perfect user interface still does not exist at present[2]

and to build a good interface

requires knowledge of both sociology and technology fields. According to major companies that are involved in

speech recognition researches, voice will be the primary interface between humans and machines in the near

future[7]

. Researchers have investigated the possibility of using voice activation in cars to enable hands free

controlling[9]

. Recently, a Hidden Markov Model (HMM)[8]

based speech recognition system was implementedin[10] to enable voice activated wheelchair controlling. Speech recognition technology[5] allows computers to

translate speech in pure audio or spoken form and convert it to text. By providing a specific grammar and

limiting the vocabulary, the system needs to recognize the speech with good recognition results. The

performance of the speech recognition in home environments depends on the implementation of the speech

recognition system interfaced with the smart chip called microcontroller[4]

with proper programming[3]

. The

main contribution of this paper is proposal, implementation and evaluation of a microcontroller based voice

activated wireless home automation system for assessing the feasibility of using voice as the unified control

method in real wireless home environments.

2. DESIGN IMPLEMENTATIONIn the global arena of technological revolution, remote control is one of the fastest growing fields where the

technology is thrust on distance and type of data command. The popular methods of remote controller are using

Radio Frequency, Frequency modulation, Infrared technology etc. These techniques have limitation of range

and are quite old established technique. The long distance technology uses GSM, GPRS network technology for

remote operation. The voice based remote operation is a modern short range remote controller and that accept

voice commands. The remote controller is designed to accept command directly from the human voice. A voice

processor is used to recognize the voice and accordingly carry out the tasks assigned in the controller.

The project designed here is a microcontroller based embedded system interfaced with a DSP based voice

processor to recognize the words. The voice processor on program mode stores the word string of 1.2 sec length

in an EEPROM and the processor can store 10nos of such data string on the EEPROM. The voice processor is

connected with a local microphone to accept direct voice and also has an option to accept voice signal from a

FM transmitter wirelessly. The selector switch can select the mode either from local to wireless. The word

strings are also field programmable by the user. The voice processor output is a digital ID for the particular

word string and that is feed to an AT89C51 microcontroller and decoded to control the devices connected to the

microcontrollers through the specific relay drivers. This is an embedded system designed to process voice and

recognize the word string and decode the words to perform the action. The voice communication to the

processor can be directly fed using a MIC. In this case the environment noise may sometime affect the

operation. To avoid the interference of environmental noise, a novel method is used to transmit a voice

command using Frequency modulated signal using a FM transmitter.

3. HARDWARE REQUIREMENTS:This hardware implementation required components are :

a)

Power Supplyb) Microphone


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c) Oscillatord) RF Amplifiere) Modulatorf) Transmitterg) FM Receiverh) Audio Power Amplifieri) Microcontroller based mother board.j) Voice Recognition modulek) Relay and Relay driverl) PMDC Motor and bi-directional motor driver

The power supply is required to drive the entire system. The microphone converts the sound waves into

electrical signals. The oscillator generates carrier waves and to enhance the strength of these waves, they are fed

to the RF Amplifier which raises the power level of the carrier waves. The modulator produces the requiredradio waves after modulation. These radio waves are transmitted in the space by a transmitter. The FM receiver

receives the transmitted radio waves. The audio power amplifier amplifies the weak signals from the FM

Receiver. The transmitter produces the required radio waves for transmitting the voice input command into the

space. The mother board consists of a microcontroller, input/output pull up registers, oscillator section and auto-

reset circuit. The voice recognition module is a completely assembled and programmable speech recognition

circuit. It has 8 bit data out which has been interfaced with the microcontroller for required development of the

project. The relays are electrically operated switches which controls the electrical appliances such as electric

bulb with the help of relay driver circuits. A doorway system has been designed to operate with the help of a

PMDC Motor and a bi-directional motor driver.

4. REAL IMPLEMENTATIONDiagram : The prototype that has been designed is shown as below :

Fig. 1 : Microcontroller Based Voice Activated Home Automation System


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Functioning : Firstly, the voice command is stored in the 8 bit CMOS static RAM with the help of the function

keys available in the voice recognition circuit. This voice command may be as Device -1 ON (Gate

Open/Close). This acts as a sample voice. Then, the working voice is fed into the microphone. It converts the

physical voice signal to electrical signal. After necessary modulation and RF amplification, this signal is

transmitted into the space by a transmitter. The receiver adjusts the centre frequency with the help of a gangcapacitor and receives the desired voice signal from the FM transmitter through wireless link. Here, CXA1619S

IC (one chip FM/AM radio IC) has been taken for reception. The voice command received is fed into the voice

recognizer circuit having a voice recognizer chip HM2007L after amplification by an audio power amplifier

LM380. The voice received is processed in the voice recognition system and stored in the memory chip

74HC573. The characteristics of this voice command are matched with that of the pre-stored sample voice. The

7-segment LED display driver IC is driven by the chip 74HC573 which acts as an input output ports allowing

interfacing with the microprocessors. IC CD4511B drives the LED 7-segment display. As soon as the module

recognizes the voice, control messages or signals are sent to the microcontroller. It must be noted that the voice

processor cannot produce sufficient current to drive the controller directly. The output from the DTMF decoder

must be compatible with the microcontroller because the microcontroller can take 5V as input voltage and can

give 5V as output voltage. This is done by the help of a signal conditioning circuit. The microcontroller then

processes the received data and switches the doorway and bulbs with the help of relay via connected driver

circuits.

The voice controlled door works with the help of a PMDC motor and a bi-directional motor driver. Here, the bi-

directional DC motor driver is configured as a Relay driver. The driver stage not only drives the motor but also

helps to control the direction of rotation. Here in this case, two relay drivers are taken in account to drive the

motor in clock wise and anti-clockwise. The D.C. Motor used in this project operates at 12 volt and carries

approximately 400mA of current. The motor driver is designed to interface the motor with microcontroller. The

microcontroller output is +5volt and can give a maximum current of 5mA. The driver stage changes the current

and voltage level suitably to drive the motor. Here we drive a PMDC motor in both the direction using two

electromagnetic relay.At normal conditions; the input of both the relay driver is zero. That means the motor is in

off condition. If the 1st

relay will go as ON and 2nd

relay will go as OFF, then the motor will run in clockwise

direction. Similarly if the 2nd

relay will go as ON and the 1st

relay will go as OFF, then the motor will run in

anticlockwise direction.

5. RESULTSThe graphs were taken with the help of a Digital Storage Oscilloscope for every voice commands for the

response of each voice controlled appliances. The response due to different voice inputs at different terminals

i.e. microphone, transmitter, receiver, audio power amplifier, signal conditioning circuit and relay driver circuit

are shown below:

a) Response at the transmitter due to Music background noise


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Fig. 1 (a) : Response Due To Music Background Noise

b) Responses due to the command Device 1-ON (Gate open/ close)

1) Response at the microphone output

Fig. 1(b) : Response at Microphone Output2) Transmitter Output Response

Fig. 2 : Response Given By Transmitting Antenna


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3) Receiver Output Response

Fig. 3 : Response Given By Receiver

4) Audio Power Amplifier Input Response

Fig. 4: Input Response of the Audio Power Amplifier

5) Output response of Audio Power Amplifier

Fig. 5 : Output Response of Audio Power Amplifier


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6) Output response of the Signal Conditioning Circuit

Fig. 6 : Output Response Due To Signal Conditioning Circuit7) Output response of the Relay driver circuit

Fig. 7 : Output Response of Relay Driver Circuit

6. CONCLUSIONThe response with different values of the input frequency shows a good and accurate rise time, fall time, duty

cycle and pulse width. The system has practical coverage up to a few meters. Confirmative voice with specific

voice pitch and frequency is desired by the speech recognizer used in this system to produce better recognition

results. The system controls extended and multiple home appliances by using speech recognition technology.

7. FUTURE SCOPEThe current system limits its application in noise free environment. Future studies should aim at making it

insensitive to noise by introducing proper noise filter into it. By making advanced and partial modifications, this

project can be used in acoustic control of vehicles braking systems thus reducing risk of accidents. It can be

applied in various applications such as voice activated wheel chairs, robotic control appliances etc. The four

electric bulbs shown in the prototype figure can be replaced for the future extension of the project by attaching

with the different physical appliances like air conditioner, television, freeze etc. This project can be done by

using soft computing on MATLAB for efficient output.


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8. REFERENCES[1] B. P. Lathi and Zhi Ding, Modern Digital and Analog Communication Systems, Fourth Edition, 2009[2] D. Spinellis, The information furnace: consolidated home control, Personal and Ubiquitous Computing,

Vol.7, Issue 1, May 2003.

[3] Dhananjay V. Gadre, Programming and Customizing the AVR Microcontroller, TMH Edition-2003[4] Douglas V. Hall, Microprocessors and Interfacing, Revised Second Edition[5] http://www.datasheetarchive.com/HM2007L-datasheet.html[6] J. Greichen, Value based home automation for todays market, IEEE Transactions on Consumer

Electronics, Vol. 38, No. 3, August 1992.

[7] J. Nielsen, Voice Interfaces: Accessing the potential. Available athttp://www.useit.com/alertbox/20030127.html

[8] L. Rabiner, A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition,Proceedings of the IEEE, Vol. 77, No. 2, February 1989.

[9] M. Nilsson, M. Ejnarsson, Speech recognition using Hidden Markov Model, Master of Science Thesis,Blekinge Institute of Technology, Sweden2002. Available at

http://www2.hh.se/staff/maej/publications/MSc%20Thesis%20-%20MiMa.pdf

[10]O. Majadalawieh, On the design of a voice-controlled robotic system using HTK, Master of AppliedScience Thesis, Dalhousie University Halifax, Nova Scotia, Canada. 2004.

[11]S. H. Park, S. H. Won, J. B. Lee, S. W. Kim, Smart homedigitally engineered domestic life, Personaland Ubiquitous Computing, Vol. 7, Issue 3-4, July 2003.

[12]W. Green, D. Gyi, R. Kalawsky, D. Atkins, Capturing user requirements for an integrated homeenvironment, Proceedings of the third Nordic conference on Human-computer interaction, NordiCHI04.

12 Kailash Pati Dutta 863 Research Article EEC August 2012

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