Digital Braille
Dept of Electronics and Communication, RVCE Page 1
Department of Electronics and Communication
R.V. College of Engineering
(An Autonomous Institution Affiliated to VTU, Belgaum)
DIGITAL BRAILLE
PROJECT REPORT
Submitted by
Dhananjaya Kumar A (1RV08EC031)
Kantharaj V (1RV08EC042)
Rakshith R (1RV08EC0123)
Rahul S Sankanur (1RV08EC077)
Under the Guidance of
Mrs Roopa J, Asst Professor
Department of Electronics and Communication Engineering
R.V.COLLEGE OF ENGINEERING,
BANGALORE-560059
Digital Braille
Dept of Electronics and Communication, RVCE Page 2
R.V. College of Engineering
(Autonomous under VTU , Belgaum)
Dept of Electronics & Communication Engineering
R.V. Vidyaniketan Post, Bangalore – 560 059
. CERTIFICATE
This is to certify that the project work entitled ―DIGITAL BRAILLE‖ is a bonafide work
carried out by
Dhananjaya Kumar A (1RV08EC031)
Kantharaj V (1RV08EC042)
Rakshith R (1RV08EC0123)
Rahul S Sankanur (1RV08EC077)
in partial fulfillment for the award of the degree of Bachelor of Engineering in Electronics
and Communication Engineering of Visvesvaraya Technological University, Belgaum
during the academic year 2011-2012 as a part of the 7th
semester mini project . It is certified
that all corrections/suggestions indicated for Internal Assessment have been incorporated in
the report deposited in the departmental library. The project report has been approved as it
satisfies the academic requirements in respect of project work prescribed for the said degree.
Signature of Guide Signature of Examiner
Mrs Roopa J
Asst Prof., ECE, RVCE
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ACKNOWLEDGMENT
The satisfaction that accompanies the successful
completion of any task would be incomplete without the
mention of the people who made it possible, whose constant
guidance and encouragement crowned all our efforts with
success. We consider our privilege to express gratitude and
thanks to the following persons for their help, encouragement
and intellectual influence during the course of the project
work.
We would like to thank Principal, R.V. College of engineering
and Prof. S. Jagannathan, head of Electronics and
Communication Engineering, RVCE, for inspiring words with
constant support extended to us during our entire course
period and for making the lab facilities available to us
whenever needed.
We sincerely thank our internal guide Mrs Roopa J, Asst
Professor, Department of Electronics and Communication
Engineering for the guidance regarding the project throughout
the entire period.
We thank all the faculty members of Department of
Electronics and Communication, our parents and friends for
their continuous support and encouragement throughout the
project work.
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CONTENTS
TOPICS PAGE NUMBER
Abstract 5
Introduction 6
Theory behind Project 7
System Overview 11
Programmer Design 13
Hardware Implementation 18
Software Implementation 20
Result and Analysis 29
Conclusion 31
Appendix 32
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Abstract
The project is the implementation of a product called DIGITAL BRAILLE. This product is
aimed at helping the visually impaired people to implement Braille code at ease and also
them communicate with the computer. It involves the implementation a key board where
inputs are such that it is similar that in the Braille script. The inputs are taken and processed
in the micro-controller. They are compared to a certain set of Braille-codes. Depending on the
code, suitable output is sent to the computer corresponding to the letter typed by the user.
In terms of system design and development , this study consists of both hardware and
software. The hardware used is the DIY Arduino board consisting of ATMEGA168
microcontroller. Along with it , the inputs are given through the six push buttons provided.
Programmer used is the USBasp in Arduino -022. FT 232 R is used for serial communication.
Codes are written in C language.
Presently , micro-phones are used extensively for the Visually impaired to interact with the
computer. This leads to a lot of errors since the input is analog voice . And moreover, in
places where they are required to give online exams , special arrangements since answers are
through voice.
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INTRODUCTION
The main problem of visually impaired people face is to communicate. They cannot read or
write as a normal man does. For this reason, Louis Braille developed a different method of
reading and writing and this language is called BRAILLE.
BRAILLE is a medium through which the visually impaired people can read and write.
However, the visually impaired people find it difficult to use BRAILLE as they have to keep
punching many holes in order to write even a single letter or a word. It also takes time for
them to read as well as they have to feel the punched holes and then identify each letter and
hence the work. This takes a very long time as well as very strenuous task and further more it
is difficult to be understood by a common man.
Therefore, our motive is to develop a product which should be an alternative to the current
BRAILLE and which can help the visually impaired people to communicate not only
amongst them but also among the whole world.
Our main objective is to help the visually impaired people to read and write with ease.
We are going to achieve this objective by implementing our product called DIGITAL
BRAILLE. Digital Braille is a product used to help the visually impaired people to interact
with the computer with the help of, microcontrollers and touch sensors or keypads. The
visually impaired people enter the Braille code using the touch sensors with ease as they
don‘t have to punch holes and this Braille code is decoded into the corresponding alphabet.
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THEORY BEHIND THE PROJECT
The Braille system is a method that is widely used by blind people to read and write, and was
the first digital form of writing.
The Braille system was based on a method of communication originally developed
by Charles Barbier in response to Napoleon's demand for a code that soldiers could use to
communicate silently and without light at night called night writing. Barbier's system of sets
of 12 embossed dots encoding 36 different sounds was too difficult for soldiers to perceive by
touch, and was rejected by the military. In 1821 he visited the National Institute for the Blind
in Paris, where he met Louis Braille. Braille identified the two major defects of the code:
first, by representing only sounds, the code was unable to give the orthography of the words;
second, the human finger could not encompass the whole symbol without moving, and so
could not move rapidly from one symbol to another. His modification was to use a 6 dot cell
— the Braille system — representing all the letters of the alphabet.
At first the system was a one-to-one transliteration of French, but soon various abbreviations
and contractions were developed, creating a system much more like shorthand.
FORM
Braille can be seen as the world's first binary encoding scheme for representing
the characters of a writing system. The system as originally invented by Braille consists of
two parts:
1. A character encoding for mapping characters of the French language to tuples of
six bits or dots.
2. A way of representing six-bit characters as raised dots in a Braille cell.
Today different Braille codes (or code pages) are used to map character sets of different
languages to the six bit cells. Different Braille codes are also used for different uses like
mathematics and music. However, because the six-dot Braille cell only offers 63 possible
combinations (26 - 1 = 63), of which some are omitted because they feel the same (having the
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same dots pattern in a different position, e.g. ⠊ and ⠔), many Braille characters have
different meanings based on their context. Therefore, character mapping is not one-to-one.
In addition to simple encoding, modern Braille transcription uses contractions to increase
reading speed.
WRITING DIGITAL BRAILLE
Braille may be produced using a slate and stylus in which each dot is created from the back
of the page, writing in mirror image, by hand, or it may be produced on a Braille typewriter
or Perkins Brailler, or produced by a Braille embosser attached to a computer. It may also be
rendered using a refreshable Braille display.
Braille has been extended to an 8-dot code, particularly for use with Braille embossers and
refreshable Braille displays. In 8-dot Braille the additional dots are added at the bottom of the
cell, giving a matrix 4 dot high by 2 dots wide. The additional dots are given the numbers 7
(for the lower-left dot) and 8 (for the lower-right dot). Eight-dot Braille has the advantages
that the case of an individual letter is directly coded in the cell containing the letter and that
all the printable ASCII characters can be represented in a single cell. All 256 (28) possible
combinations of 8 dots are encoded by the Unicode standard. Braille with six dots is
frequently stored as Braille ASCII.
The first ten letters of the alphabet are formed using only the top four dots (1, 2, 4, and 5).
Reminiscent of Greek numerals, these symbols also represent the digits 1 through 9 and
0 (preceded by the symbol [number follows]; [number follows]j also stands for 10, within
context).[5]
Adding dot 3 forms the next ten letters, and adding dot 6 forms the last six letters
(except w) and the words and, for, of, the, and with. Omitting dot 3 from the letters U-Z and
the five word symbols form nine digraphs (ch, gh, sh, th, wh, ed, er, ou, and ow) and the
letter w.
Fig.1 Shows the Braille code implementations for different letters and other symbols. It also
shows Braille contractions to implement small words using the Braille code.
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PAGE DEMENSIONS
Most Braille embossers support between 34 and 37 cells per line, and between 25 and 28
lines per page. A manually-operated Perkins Braille typewriter supports a maximum of 42
cells per line (its margins are adjustable), and typical paper allows 25 lines per page. A large
interlining Stains by has 36 cells per line and 18 lines per page. An A4-sized Marburg Braille
frame, which allows interpoint Braille (dots on both sides of the page, positioned out of
phase so they do not interfere with each other) has 30 cells per line and 27 lines per page.
A refreshable Braille display typically has one line of between 18 and 40 cells, although 80 is
possible.
Fig.1 Braille code implementations of various alphabet
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Fig 2. Braille code implementations (GRADE 2 BRAILLE)
Braille Unicode
Braille was added to the Unicode Standard in September, 1999 with the release of version
3.0.
The Unicode block for Braille is U+2800 ... U+28FF:
Unicode is a computing industry standard for the consistent encoding, representation and
handling of text expressed in most of the world's writing systems. Developed in conjunction
with the Universal Character Set standard and published in book form as The Unicode
Standard, the latest version of Unicode consists of a repertoire of more than
109,000 characters covering 93 scripts, a set of code charts for visual reference, an encoding
methodology and set of standard character encodings, an enumeration of character properties
such as upper and lower case, a set of reference data computer files, and a number of related
items, such as character properties, rules for normalization, decomposition, collation,
rendering, and bidirectional display order (for the correct display of text containing both
right-to-left scripts, such as Arabic and Hebrew, and left-to-right scripts).[1]
As of 2011, the
most recent major revision of Unicode isUnicode 6.0.
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SYSTEM OVERVIEW
IMPLEMENTATION
We have 6 variables depicting the 6 dots in the Braille. These 6 keys are used to represent all
the alphabets through various permutations. The 26 alphabets are divided in 3 groups of 10,
10 and 6.There is a vast similarity of codes introduced between these groups to have greater
simplicity.
To distinguish between the alphabets of one group to another, GROUP SELECTORS are
used. S3 and s6 are used.
Fig.4 Shows the picture of BRAILLE keypad which we are going to use in DIGITAL Braille
for entering the Braille code.
Fig 4.Digital Braille Keypad
The group selectors are implemented as shown in the example below and note
the use of line selectors in ‗K‘ and ‗U‘.
Alphabets Keys
A s1
B s1,s2
C s1,s4
K s1,s3
U s1,s3,s6
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Fig 5. Braille codes
The fig 6.shows the basic block diagram of DIGITAL BRAILLE.
Fig 6.Block diagram of Digital Braille
The integral part of DIGITAL BRAILLE is ATMEGA168 Microcontroller. We are using 6
keys keypad to enter the Braille code. The six keys as shown in the fig 6 is used to simulate
the six dots of the Braille Cell. After the Braille code is entered in the keypad, the
ATMEGA168 microcontroller decodes the entered digital Braille code into English alphabets
by using a look up table. . Once the Braille code has been decoded, it is converted to speech
using APIs provided by windows. This enables the visually impaired people to keep track of
what code they are entering.
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PROGRAMMER DESIGN
ARDUINO MICRCONTROLLER BOARD
The Arduino microcontroller board is one of the integral parts of DIGITAL BRAILLE. It is
used for programming the ATMEGA168 microcontroller.
Fig 7. Arduino UNO Board
Fig. 7 shows the original Arduino UNO board.
However, we have developed our own Arduino board as shown in the fig 8.
Fig 8. DIY – DUINO
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FEATURES OF ARDUINO WE USED:-
POWER
The Arduino Uno can be powered via the USB connection or with an external power
supply. The power source is selected automatically.
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or
battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the
board's power jack. The board can operate on an external supply of 7 to 12 volts.
The power pins are as follows:
VIN: The input voltage to the Arduino board when it's using an external power
source.
5V: The regulated power supply used to power the microcontroller and other
components on the board.
3V3: A 3.3 volt supply generated by the on-board regulator. Maximum current draw
is 50mA.
GND: Ground pins.
MEMORY
The ATmega168 has 16 KB (with 0.5 KB used for the boot loader).
It also has 1 KB of SRAM and 512 B of EEPROM.
INPUT AND OUTPUT
Each of the 14 digital pins on the Uno can be used as an input or output, using
pinMode(), digitalWrite() and digitalRead() functions. They operate at 5 volts. Each pin can
provide or receive a maximum of 40 mA and has an internal pull-up resistor of 20-50k Ohms.
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Additional functions (digital):
Serial: 0 (RX) and 1 (TX): Used to receive (RX) and transmit (TX) TTL serial data.
These pins are connected to the corresponding pins of the FT232R USB-to-TTL
Serial chip.
External Interrupts: 2 and 3: These pins can be configured to trigger an interrupt on
a low value, a rising or falling edge, or a change in value.
PWM: 3, 5, 6, 9, 10, and 11: Provide 8-bit PWM output with the analogWrite()
function.
SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK): These pins support SPI
communication using the SPI library.
LED: 13: There is a built-in LED connected to digital pin 13(active high).
The Uno has 6 analog inputs, labeled A0 through A5, each of which provide 10 bits of
resolution (i.e. 1024 different values).
Additional functions (analog):
I2C: 4 (SDA) and 5 (SCL): Support I2C (TWI) communication using the Wire
library.
Reset: Bring this line LOW to reset the microcontroller.
COMMUNICATION
The Arduino Uno has a number of facilities for communicating with a computer,
another Arduino, or other microcontrollers. The ATmega168 provides UART TTL (5V)
serial communication, which is available on digital pins 0 (RX) and 1 (TX). An ATmega8U2
on the board channels this serial communication over USB and appears as a virtual com port
to software on the computer. The Arduino software includes a serial monitor which allows
simple textual data to be sent to and from the Arduino board. The RX and TX LEDs on the
board will flash when data is being transmitted via the USB-to-serial chip and USB
connection to the computer. A Software Serial library allows for serial communication on any
of the Uno's digital pins.
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The ATmega168 also supports I2C (TWI) and SPI communication. The Arduino
software includes a Wire library to simplify use of the I2C bus; see the documentation for
details. For SPI communication, use the SPI library.
PROGRAMMING
The ATmega168 on the Arduino Uno comes pre-burned with a boot loader that
allows you to upload new code to it without the use of an external hardware programmer. It
communicates using the original STK500 protocol.
AUTOMATIC (SOFTWARE) RESET
Arduino Uno can be reset using software. One of the hardware flow control lines
(DTR) of the FT232R is connected to the reset line of the Atmega168 via capacitor. When
this line is taken low, the reset line drops long enough to reset the chip.
STEPS TO PREPARE DIY ARDUINO BOARD
We take rectangular copper board 8‖ x 12‖. Sand the top of the copper with a fine sand
paper. This gives it some more surface area for the toner to stick to.
The pattern is transferred on the PCB by ironing the pattern on the PCB.
Etch the board using FeCl3.
After performing the above three steps, the board looks like as shown in fig 9.
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Fig 9. Pattern trancfered onto copper board
The holes are drilled and all the components are placed as shown in fig 10.
Fig 10. Arduino board with all the components placed.
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HARDWARE IMPLEMENTATION
1. DIY Arduino board with Atmega168 Microcontroller
2. Matrix keypad
3. PCB
4. FT232 CABLE
5. Resistors, capacitors, multimeters
6. Soldering gun
INTERFACING OF KEYBOARD WITH ATMEGA168
Fig 11. Interfacing of keypad with atmega168
The keypad is interfaced with the atmega168 as shown in the figure 11.
Identifying the keypad pins
We require 6 push buttons to represent the 6 dots of the Braille cell.
We attached 6 SPDT push buttons the board. SPDT push buttons mean single pole double
throw Push Button. The switch has a contact arm that is connected to a actuating force with
that actuating force counteracted by another force (such as a spring). The actuating force may
be a pressure source, as a pressure switch, a flow, as a sail switch, a lever, as in a position
switch.
The single pole defines that the switch may be connected to a single power source, the
terminal is typically denoted as C for common.
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The double throw means that the switch arm has 2 electrical contacts. The normally open
contact, typically denoted as NO, is open with the switch not actuated (power may NOT flow
through this contact when the switch is in its unactuated state). The normally closed, typically
denoted as NC, is closed when the switch is unactuated (power may flow through this contact
when the switch is in its unactuated state) and is connected to the ground. When the force
actuates the switch, contact closure reverses (power may flow through the NC switch and
may NOT flow through the NO switch).
Diagram:
||-----C----|/|
NO--C—NC
The power leg is connected to C and the switch leg(s) are connected to the NO or NC or the
ground.
The 6 keys are named K1, K2, K3, K4, K5, and K6.
Key K1 is attached to PIN 2, Key K2 is attached to PIN 3, Key K3 is attached to PIN 4, Key
K4 is attached to PIN 5, Key K5 is attached to PIN 6, and Key K6 is attached to PIN 7.
Using these six keys, we are implementing Braille code. We have given a some delay while
programming and we have to press all the push buttons to enter the required letter within this
delay to obtain the required letter else only those buttons which have been pressed within that
delay while be considered and the corresponding letter of that code will be displayed. The
delay we have given is around 500 milliseconds.
Which ever button is actuated, the corresponding input pin will receive a logic one. After the
said delay, the output is sent to the serial window using a FT232 cable. This cable is used for
converting serial to USB as the USB is attached to the USB port of the computer where we
see the output in the serial window.
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SOFTWARE IMPLEMENTATION
FLOW CHART
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The above is the flow chart of the code used for implementing Digital Braille using Arduino
programmer for programming Atmega168.
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CODE SNIPPET
/* Initializing the input and output pins of Atmega168 and setting up the baud rate to 9600*/
void setup()
{
Serial.begin(9600);
pinMode(2,INPUT);
pinMode(3,INPUT);
pinMode(4,INPUT);
pinMode(5,INPUT);
pinMode(6,INPUT);
pinMode(7,INPUT);
}// End of setup
/* Starting of infinite loop */
void loop()
{
/* assigning input to the variables */
int a = digitalRead(2);
int b = digitalRead(3);
int c = digitalRead(4);
int d = digitalRead(5);
int e = digitalRead(6);
int f = digitalRead(7);
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if(e&f&!a)
{
if(!b)
{
if(!d)
{
if(!c)
Serial.println('G'); //print letter G serially
else
Serial.println('D'); //print letter D serially
}
else if(!c)
Serial.println('F'); //print letter F serially
else
Serial.println('C'); //print letter C serially
}
else if(!c)
{
if(!d)
Serial.println('H'); //print letter H serially
else
Serial.println('B'); //print letter B serially
}
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else if(!d)
Serial.println('E'); //print letter E serially
else
Serial.println('A'); //print letter A serially
}
else if(!b)
{
if(!d&!c&f&e)
{
Serial.println('J'); //print letter J serially
}
else if(!c&f&e)
{
Serial.println('I'); //print letter T serially
}
}
if(f&!e)
{
if(!a)
{
if(!b)
{
if(!d)
{
if(!c)
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Serial.println('Q'); //print letter Q serially
else
Serial.println('N'); //print letter N serially
}
else if(!c)
Serial.println('P'); //print letter P serially
else
Serial.println('M'); //print letter M serially
}
else if(!c)
{
if(!d)
Serial.println('R'); //print letter R serially
else
Serial.println('L'); //print letter L serially
}
else if(!d)
Serial.println('O'); //print letter O serially
else
Serial.println('K'); //print letter K serially
}
else if(!b)
{
if(!d&!c)
{
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Serial.println('T'); //print letter T serially
}
else if(!c)
{
Serial.println('S'); //print letter S serially
}
}
}
if(!e&!f)
{
if(!a)
{
if(!b)
{
if(!d)
Serial.println('Y'); //print letter Y serially
else
Serial.println('X'); //print letter X serially
}
else if(!c)
Serial.println('V'); //print letter V serially
else if(!d)
Serial.println('Z'); //print letter Z serially
else
Serial.println('U'); //print letter U serially
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}
}
if(a&!b&!c&!d&e&!f)
Serial.println('W'); //print letter W serially
/* to give sufficient delay to press all the keys */
delay(500);
} //End of void loop
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REFLECTIONS
Result
The project demonstrates as to how the visually impaired people can write the Braille code
using keypads interfaced with the microcontroller (or computer).
The 6 keys on the keypad depict the 6 dots on the Braille cell used by the visually impaired
people to write the Braille code. The keypad is interfaced with the ATMEGA168
microcontroller. The required Braille code is entered using the keypad and the input to this
keypad is sent to the microcontroller. The microcontroller then decodes the entered Braille
code to the corresponding English alphabets and displayed on the serial window. Hence, as
the Braille code entered is translated into English, even people who do not know the Braille
code can understand what the visually impaired people are writing.
The following are the results we have obtained from the implementation of the DIGITAL
BRAILLE.
Inputs from the keys Obtained
Alphabet
Required
Alphabet K6 K5 K4 K3 K2 K1
0 0 0 0 0 1 A A
0 0 0 1 0 1 B B
0 0 0 0 1 1 C C
0 0 1 0 1 1 D D
0 0 1 0 0 1 E E
0 0 0 1 1 1 F F
0 0 1 1 1 1 G G
0 0 1 1 0 1 H H
0 0 1 0 1 0 I I
0 0 1 1 1 0 J J
0 1 0 0 0 1 K K
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0 1 0 1 0 1 L L
0 1 0 0 1 1 M M
0 1 1 0 1 1 N N
0 1 1 0 0 1 O O
0 1 0 1 1 1 P P
0 1 1 1 1 1 Q Q
0 1 1 1 0 1 R R
0 1 0 1 1 0 S S
0 1 1 1 1 0 T T
1 1 0 0 0 1 U U
1 1 0 1 0 1 V V
1 0 1 1 1 0 W W
1 1 0 0 1 1 X X
1 1 1 0 1 1 Y Y
1 1 1 0 0 1 Z Z
Learning
There are millions of visually impaired people around the world and these people find
it difficult to write the Braille code as they have to keep punching holes on the Braille
cell. As students, we feel privileged to have developed a product which helps the
visually impaired people to easily write the Braille code and also interact with other
people.
Our programming and logic analyzing skills were tested and bettered as we coded for
the project
We learnt a great deal with certain aspects of controllers as we implemented our
theoretical knowledge and also expanded our horizons to the practical world.
Finally, we learnt to work as a team and support each other through the course of the
project.
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CONCLUSION
The project successfully demonstrates the implementation of the Braille code using
microcontrollers.
Digital Braille can be implemented on large scale due to the following advantages: -
It mainly helps the visually impaired people to enter the Braille code with utmost ease
as they don‘t have to keep punching holes on the Braille cell on the paper.
Since the entered Braille code is converted to corresponding English words, people who
do not know Braille can also understand what a visually impaired person is typing in the
Braille code.
During any exams, the visually impaired people are given external help by appointing a
person to write down the answers for them. With the implementation of the Digital
Braille, this problem is solved as the visually impaired people need not have external
aide to write his answers. This is because the entered Braille code is converted to
English or for the matter any corresponding language and it is easy for the examiner to
understand what answers the visually impaired people have written. Digital Braille thus
helps the people to live independently and don‘t have to rely on others for written any
exams.
It is one time investment which can be used throughout the life time.
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APPENDIX
ATMEGA168 DATASHEET
We are using ATMEGA168 microcontroller for implementation of DIGITAL BRAILLE.
The following are the features of ATMEGA168 microcontroller:
Features:
High Performance, Low Power Atmel AVR 8-Bit Microcontroller
Advanced RISC Architecture
32 x 8 General Purpose Working Registers
Fully Static Operation
Up to 20 MIPS Throughput at 20MHz
On-chip 2-cycle Multiplier
High Endurance Non-volatile Memory Segments
16KBytes of In-System Self-Programmable Flash program memory
512 Bytes EEPROM
1KBytes Internal SRAM
Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
Peripheral Features
Two 8-bit Timer/Counters with Separate Pre-scalar and Compare Mode One
16-bit timer/Counter with Separate Pre-scalar, Compare Mode, and Capture
I/O and Packages
23 Programmable I/O Lines
28-pin PDIP
Operating Voltage:
1.8 - 5.5V
Temperature Range:
-40°C to 85°C
Speed Grade:
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0 - [email protected] - 5.5V, 0 - [email protected] - 5.5.V, 0 - 20MHz @ 4.5 - 5.5V
Power Consumption at 1MHz, 1.8V, 25°C
Active Mode: 0.2mA and Power-down Mode: 0.1μA
Power-save Mode: 0.75μA (Including 32kHz RTC)