Abstract- Now a
day notice board has become an important thing in institutes/organization or
public places like railway stations, bus stands and hospitals. But to use the
paper notices stacked on a notice board is a time taking and expensive process
and there is wastage lot of time, paper and labour. The notice board is used to
display the information in an effective way to the people, but to update the
messages instantly is not easy on the notice board. This project, deals about
an advanced Hi-Tech wireless Notice Board. This system is enhanced to display
the latest information through an Android application of smart phones or tablet
which can be connected to Bluetooth (HC-05). At the receiver end a low cost microcontroller
(arduino Uno) is programmed to receive and display messages in the LCD
display.  In order to display notices
user can use the application to speak and then verbalized voice into text and
click on send button to get it displayed on LCD screen. In this project, we are
going to develop an on-line speech-to-text engine. The system takes speech as
input through microphone and a sampled speech is processed to identify the
verbalized text. Speech recognition is done via the Internet, connecting to Google’s
server. The application is adapted to input messages in English. Speech
recognition for Voice uses a technique based on hidden Markov models (HMM –
Hidden Markov Model). It is the most successful and flexible approach for
speech recognition. 


Keywords— LCD, HC-05, android, arduino Uno, HMM.

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The idea behind voice
operated electronic board exploits to point out the messages and regulate them
by exploit our own voice. We have already used GSM primarily based Electronic
board, but speech controlled board has extra advantage. User needs to formulate
command in his/her own voice to regulate the messages displayed on electronic
board 6. User has to install automation applications in his/her smart phones,
they are easy to
use, promising and durable devices that help in performing day to day
tasks,  voice
recognition is finished within the automaton application. Embedded
systems using wireless technologies are widely used for communicating with
peripheral devices. The GSM based wireless communication for different
applications are implemented and proposed. A simple low cost wireless android
based notice board is developed and presented. This system uses a wireless
serial data communication in displaying messages on a remote digital notice
board with Bluetooth connection. Bluetooth and Wi-Fi communication for personal
digital assistant (PDA) devices are used for transmitting the alpha-numeric
text messages using Android based Application programs available for Using the
Bluetooth based serial data communication technique, the corresponding
transceiver module has been interfaced with microcontroller board at the
receiver end. For this purpose, a low cost microcontroller board (Arduino Uno)
is programmed to receive alphanumeric text messages in the Bluetooth mode. The
proposed system will reduces the resources like the human effort, paper,
printer ink and cost for manual changing of the notices in the noticeboard. Bluetooth wireless technology is a technique within the
communication arena, and it is one in all the quickest growing fields within
the wireless technologies. Bluetooth technology handles the wireless a part of
the communication channel; it is utilized in this project to transmit and
receive data between devices. Whereas, a phone is just quite a phone recently,
it is good phone the quantity of applications being engineered on a good varies
of platforms for smart phone is astounding. A computer system can be used as a
speech synthesizer and can be implemented in software or hardware products with
an artificial production of human speech1.


An Arm processor with
development board, it is an arm development board which consists of 32-bit
arm7tdmi-s microcontroller in a tiny lqfp64 package. The microcontroller in it
is lpc2148. There are LCD’s, a 2*16 alphanumeric LCD also available in the
development board. Other than these are two uart, usb 2.0, jtag, vga, power
jack, buzzer, sd/mmc and buttons.  Android
application an application named home automation has been used to switch on/off
dc motors using on/off button and another button for typing and sending a notice
to be displayed in the lcd as shown in the fig. 1. A 16*2 alphanumeric LCD
display has been used to display the notice sent by the authorised user. It is
a 16*2 screen which means it can display 16 alphanumeric characters in each
line and there are two lines for display in total which sums upto a maximum of
32 characters being displayed at a time. It has 8 data pins since each
character is of 8 bits and three other pins namely, enable, read/write and
register select. Whenever the enable pin is low, LCD is off and it is on if the
pin is high. The read/write pin, if high, reads the data from LCD and if low,
writes data in it. The register select pin decides the type of data transferred

through the data pins. If it is high, a character is
written in LCD and if low, command is sent to LCD.

The simple and low-cost wireless Android based
notice board system is developed to remotely send the desired information
instantly to the intended users using Bluetooth 
transceiver module interfaced with a low cost Arduino UNO
microcontroller board. The communication mode Bluetooth is selected for data
communication using the corresponding transceiver module with the
microcontroller. Arduino UNO microcontroller board is programmed as a client
using Arduino software to receive the message from remote user in Bluetooth
based wireless communication technology. An Adruino’s
microcontroller is also pre-programmed with a boot loader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an
external chip programmer. This makes using an
Arduino more straightforward by allowing the use of an ordinary computer as the
programmer. Currently, opt boot boot loader is the default boot loader
installed on Arduino UNO.

 At a conceptual level, when using the Arduino
integrated development environment, all boards are programmed over a serial
connection. Its implementation varies with the hardware version. A level
shifter circuit is used in the serial Arduino Boards which converts
between RS-232 logic levels and transistor–transistor logic (TTL) level signals5. A Universal serial Bus (USB),
implemented using USB-to-serial adapter chips such as the FTDI FT232 in the current Arduino boards are programmed. A Uno
boards substitutes the FTDI chip with a separate AVR chip containing
USB-to-serial firmware, which is reprogrammable via its own ICSP header. Other
variants, such as the Arduino Mini and the unofficial Boarduino, use a
detachable USB-to-serial adapter board or cable, Bluetooth or other methods, the Arduino IDE standard AVR in-system programming (ISP)
is used instead of a traditional microcontroller tools.



The Bluetooth wireless technology
is a Personal Area Networks (PANs) in the range between 10-15 meters. And it
uses the 2.45 GHz frequency band for connection. A HC-05 Bluetooth module has
been interfaced with the microcontroller board (Arduino UNO) using serial communication.
The module’s Media Access Control address is
used by Android application program (Bluetooth Terminal) which allows only this
device to communicate with the Smartphone for controlling the external devices.
The interconnection of Android PDA with the external Bluetooth devices like
HC-05 Bluetooth module, using Bluetooth terminal for transmitting or receiving
the data in form of hex or string. Using the smart phone based wireless notice
board in Bluetooth communication mode the user can send the alphanumeric text
message instantly once the connection is established between Android based PDA
and Bluetooth device (HC-05). The notice on the LCD display can be changed at
any time by resending the new message from PDA using android application
program that is Bluetooth technology. The new message will overwrite the
previous message making the system very simple and easy to use. The
implementation of Android based wireless notice board using Bluetooth communication
is shown in Fig. 2 below.


Fig.2. Bluetooth Wireless notice board based on smart phones

Voice Recognition
Activity is start-up activity defined as launcher in AndroidManifest.xml file.
REQUEST_CODE is static integer variable, declared on the beginning of activity
and used to confirm response when engine for speech recognition is started.
REQUEST_CODE has positive value. Results of recognition are saved in variable
declared as List View type.  Method on
Create is called when activity is initiated. 
This is where the most initialization goes: setContentView
(R.layout.voice_recognition) is used to inflate the user interface defined in
res > layout > voice_recognition.xml, and findViewById (int) to
programmatically interact with widgets in the user interface.

First it will check the mobile phone, on which
application is installed, has speech recognition facility. Package Manager is
class for retrieving various kinds of information related to the application
packages that are currently installed on the device. FunctiongetPackageManager
() returns Package Manager Instance to find global package information. Using
this class, we can detect if the phone has a possibility for speech
recognition. If a mobile device doesn’t have one of many Google’s applications
which integrate speech recognition, further work of this application Voice SMS
will be disabled and message on the screen will be “Recognizer not present”.
Recognition process is done trough one of Google’s speech recognition
applications. If recognition activity is present, user can start the speech
recognition by pressing on the button and thus launching startActivityForResult
(Intent intent, intrequestCode). The
application broadcast an intent that requests voice recognition by using method
startActivityForResult(), which includes an extra parameter that specifies one
of two language models and intent.putExtra (Recognizer Intent) is defined.

speech recognition contains feature extraction and feature matching modules.
The feature extraction module converts speech waveform to some type of
representation for further analysis and processing, this extracted information
is known as feature vector. A front end module is used for converting voice
signal to feature vector by processing the signal. As shown in above block
diagram input to front-end is noise free voice sample and output of it is
feature vector. An unidentified voice sample is scored against acoustic model
is obtained from extracted feature vector, a hypothetical description with max
score wins, and its output is considered as recognized word is done by feature
matching. Following are the few methods for implementing front-end (for
extracting feature factor) as shown in fig.3.


MFCC (Mel-Frequency Cepstrum Coincident): A form of the short-term power spectrum of a sound, based on a linear cosine transform of a log power spectrum on a nonlinear mel scale of
frequency is known as mel-frequency cepstrum (MFC). Mel-frequency cepstral
coefficients (MFCCs) are coefficients that collectively make up an
MFC.They are derived from a type of cepstral representation
of the audio clip (a nonlinear “spectrum-of-a-spectrum”)

 • LPC (Linear Predictive Coding) Once the
feature vector are obtained we build the acoustic model. The acoustic model is
used to score the unknown voice sample. The obtained output of front-end is
given as a input to the acoustic model which is shown in the block diagram.
Different types of acoustic model are • VQ-Code Book 1 • GMM-Gaussian Mixture Model Acoustic Model Representation:
In speech recognition, basic unit of sound is phoneme. Phoneme is a minimal
unit that serves to distinguish between meanings of words. For example sequence
of phoneme for “CAT” is K A and T. In English language there are nearly around
46 phonemes. We can construct any word from English dictionary using proper
concatenation of this phoneme. A given word is recognized, a phoneme from voice
sample is extracted.



Fig.4. Data flow


LCD initialization: For
initialization, the pins R/W is kept low (write), RS is kept low (command
register selected) and then command is sent through the 4-bit mode. But to
place the command into command register, E pin is transitioned from high to low
each time a byte is sent to the LCD. The commands sent for initialization in
hexadecimal are, 28H, 20H, 06H, 01H and 80H. 2) Sending data to LCD: Sending of
data involves following steps: • R/w is set low (write operation selected). •
RS is set high (data register selected). • The data byte is sent through the 4
data lines. • E pin is transitioned from high to low for data to be placed into
data register. • The above steps are repeated to send other bytes of data.



1) Notice board with wireless is easy to
install and use without wasting any resources.

2) It is really helpful for disabled or
handicapped people so that they can only speak and same is displayed on LCD

3) It will reduce the use of resources
like paper and pen and hence deforestation can be turned into aforestation.



By introducing the concept of wireless technology in
the Field of the communication we can make our communication more efficient and
faster, with greater efficiency. We have developed a voice control Bluetooth
wireless android application for a notice board which will display the messages
with less errors and maintenance. And this system can be used in colleges,
school, offices, railway station and commercial as well as personal used which
reduces the use of a resources like pen, paper etc. In future we can apply this
method for remote teaching classes.