Microcontroller Based Voice Activated Wireless Automation System

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2 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

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Microcontroller Based Voice Activated
Wireless Automation

System

Dr. P. Rai
1
, Vineet Shekhar
2
, Kailash Pati Dutta
3

1.

H.O.D.,

Deptt. Of Electrical Engineering, B.I.T. Sindri
, Dhanbad

2

Asst. Professor, Electrical Engg., H.E.C. Sonepat, Haryana

3

Research Scholar,

Electrical Engineering, B.I.T. Sindri,

Dhanbad


ABSTRACT

This paper

presents the proposal, design and implementation of a microcontroller based voice
activated wireless home 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 comma
nds 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 contro
l 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
, Relay

I.

INTRODUCTION


Over

the

past
decade, technology has dramatically changed o
ur life and living styles. The
i
nternet

has
m
ade
i
t

poss
i
b
l
e for people

to

connect

to

t
h
e

world

without stepping

out of

t
h
e
house

and

w
i
reless

co
mm
unication [1]

has given people t
h
e convenience

of

keeping

in

touch

with

each other anyti
m
e an
y
where. The design of
new

future

house

[
1
1
] is
full

of advanced
technologies.

T
h
ese

new

t
echnolog
i
es

offer

ho
m
eowners

a

m
o
re co
m
f
ortable

ho
m
e

environment

doing automation

which
refers

to

any process

t
h
at gives re
m
o
te

or

a
ut
o
m
atic

control of ho
m
e devices and appliances.

The
challenge

to

design

better auto
m
ation

products is
to acco
mm
odate the variation a
m
ong different

users

[6
].

Also, a b
e
tter user interface design can
be t
h
e

sol
u
tion

to

so
m
e

existing

a
utomation

design

prob
le
m
s

[1
2
]
. 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

m
ajor co
m
p
anies t
h
at are involved

in

speech

recognition

researches,

voice will

be the pri
m
ary interface between hu
m
ans

and
m
achines in the
near fut
u
re

[
7
]
.

Researchers

h
a
v
e i
nv
esti
g
ated

t
h
e
po
ssi
b
ility
o
f

u
si
n
g
vo
ice acti
v
ati
o
n

in

cars

to

e
n
a
b
le
h
ands free controlling [
9
]
. Recently, a Hidden Markov

Model

(HMM)

[8
] based speech
recog
nition system was

i
m
p
le
m
e
n
ted

in

[
1
0
]

to

enable voice activated wheelchair controlling.
Speech

recognition

te
c
hnology

[
5
]
allows

co
m
puters

to translate

speech

in

pure

audio

or

spoken

form

and

convert

it

to text.
B
y providing a specific gra
mm
ar and li
m
iting

the

vocabulary
,

the

system needs

to

recognize

the
speech with

good

recognition

results.

The
performance of the
speech recognition

in

ho
m
e

env
i
ron
m
en
ts depends on the implementation of
the speech recognition system interfaced with the smart chip called mic
rocontroller
[4
] with
proper programming
[3
].
Th
e

m
ain

con
t
r
i
bu
ti
o
n

o
f

t
h
is paper

is

proposal,

i
m
ple
m
entation

and

evaluation

of

a microcontroller based voice activated wireless home automation system

for

assessing

the

feasibility

of

using

voice as

t
h
e

unif
ied

control
m
ethod

in

real w
i
reless

ho
m
e
env
i
ron
m
en
t
s.


II.

DESIGN IMPLEMENTATION


In 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 po
pular 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 w
ord 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 transmitt
er 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 microco
ntroller 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 commu
nication 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
modulate
d signal using a FM transmitter.

I.

HARDWARE REQUIREMENT
S
:

This hardware implementation required

components are
:

a)

Power Supply

b)

Microphone

c)

Oscillator

d)

RF Amplifier

e)

Modulator

f)


Transmitter

g)


FM Receiver

h)

Audio Power Amplifier

i)

Microcontroller

based mother board.

j)

Vo
ice Recognition module

k)

Relay and Relay driver

l)

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 osc
illator 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 required radio waves after modulation. These radio
waves are transmitted in the space by a transmitter. T
he 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 cons
ists 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 t
he
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 w
ith the help of a PMDC Motor
and a bi
-
directional motor driver.

III.

REAL IMPLEMENTATION

Diagram:

The prototype that has been designed is shown as below:


(
Figure 1: Microcontroller based voice activated home automation system
)


FUNCTIONING

Firstly,

the voice
co
mmand 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 th
e
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 gang capacit
or 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. T
he voice com
mand
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 sa
mple 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,

contro
l 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 mi
crocontroller 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 m
icrocontroller then processes the received data

an
d

switch
es the
doorway and bulbs with the help of relay

via conn
ected 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 b
oth the direction
using two electromagnetic relay..
At normal condition, the input of both the relay driver is zero.
That means the motor is in off condition. If the 1
st

relay will go as ON and 2
nd

relay will go as
OFF, then the motor will run in clockwise
direction. Similarly if the 2
nd

relay will go as ON and
the 1
st

relay will go as OFF, then the motor will run in anticlockwise direction.



IV.

RESULTS


The graphs were taken with the help of a Digital Storage Oscilloscope for every voice commands
for the re
sponse 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


(
Figure a1
: Response due to music background noise)

b) Responses due to the command “Device 1
-
ON


(
Gate
open/ close
)

1) Response at the microphone output


(Figure b1
: Response at microphone output)

2) Tr
ansmitter Output Response


(Figure b2
: Response given by transmitting antenna)

3) Receiver Output Response


(Figure
b3
: Res
ponse given by receiver
)

4) Audio Power Amplifier input response


(Figure
b4
: Input response of the audio power amplifier)

5) O
utput response of audio power amplifier


(Figure
b5
: Output response of audio power amplifier)

6) Output response of the Signal conditioning circuit


(
Figure

b6
: Output response due to signal conditioning circuit
)

7) Output response of the Relay driver
circuit


(Figure
b7
: Output response of Relay Driver circuit)


V.

CONCLUSION

The response with different values o
f 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 fe
w 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 techn
ology
.

VI. FUTURE SCOPE

The 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 fig
ure
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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