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BRAILLE EMBOSSER

AN INTERNSHIP REPORT

Submitted by

SRIPRIYA SRINIVASAN (2016105069)

NIVETHITHAI E (2016105056)

GUHAN R (2016105531)

in partial fulfillment for the Summer Internship Program

offered by

ELECTRONICS AND COMMUNICATION ENGINEERING

ANNA UNIVERSITY

COLLEGE OF ENGINEERING GUINDY

ANNA UNIVERSITY :: CHENNAI 600 025

MAY - JUNE 2018

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COLLEGE OF ENGINEERING GUINDY

ANNA UNIVERSITY :: CHENNAI 600 025

APRIL 2018

INTERNSHIP CERTIFICATE

Certified that this internship report “Braille Embosser” is the work of

SRIPRIYA SRINIVASAN (2016105069), NIVETHITHAI E (2016105056),

GUHAN R (2016105531) who carried out the internship project work under

my supervision from 8th May, 2018 to 31st May, 2018.

DR. S. MUTTAN

HEAD OF THE DEPARTMENT

Professor

ECE Department

College of Engineering Guindy

Anna University, Chennai – 25.

DR. D. SRIDHARAN

CO-ORDINATOR

Professor

ECE Department

College of Engineering Guindy

Anna University Chennai - 25

DR. N.RAMADOSS

SUPERVISOR

Associate Professor

ECE Department

College of Engineering Guindy

Anna University Chennai - 25

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ACKNOWLEDGEMENT

The final outcome of this project required a lot of guidance and assistance from

many people and we are extremely privileged to have got this all along the

completion of this project. All that we have done is only due to such supervision

and assistance and we would not forget to thank them.

We respect and thank our Dean Dr. T.V.Geetha for providing us with this

Summer Internship opportunity as it was a great learning experience for all of

us.

We respect and thank the Department of Electronics and Communication

Engineering and Dr.Muttan the HOD, Department of ECE, for providing us the

infrastructure for the completion of our internship project.

We thank Dr.D.Sridharan for allowing us to us the components and facilities of

the Electronics and Communication Department.

We owe our deep gratitude to our project guide and coordinator

Dr.N.Ramadass, who took keen interest on our project work and guided us all

along, till the completion of our project work by providing all the necessary

information for developing a good system.

SripriyaSrinvasan

Nivethithai E

Guhan R

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ABSTRACT

This report presents a Braille Embosser that is used to create

impressions of Braille characters on a sheet of paper using a Delta

Positioner. The Positioner has three arms of the setup inclined at 120

degrees which move the end effectors to the desired location for printing

desired characters. The end of the effectors have a triangular base that has

a simple writing tool such as a pen or sketch attached to mark the

impressions. The desired location is achieved by the proper movement of

the arms. Three stepper motors are used to control the movement of the

end effectors. The stepper motors are driven by a battery power source and

are controlled by the microcontroller. The stepper motor is interfaced with

the Arduino with the help of a stepper motor driver. The implementation

is done and the entire setup functions using the microcontroller.

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TABLE OF CONTENTS

CH NO. TITLE PAGENO.

ABSTRACT (ENGLISH)

TABLE OF CONTENTS

LIST OF FIGURES

1. OVERVIEW

1.1. Introduction

1.2 Objective of This Project

2. BRAILLE EMBOSSER AND

STEPPER MOTOR

2.1. Introduction – Braille Embosser.

2.2 Six Wire Stepper Motor and it’s different.

Configurations

2.3 Identification of Common Wire in a Stepper Motor.

2.4. Four Wire Stepper Motor and interfacing with.

Arduino Uno

2.5 Stepper motor with 4x4 matrix keypad

3… XYZ MOVEMENTS.

3.1 Cartesian Type

3.1.1 Advantages

3.1.2Disadvantages

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3.2 Delta Type

3.2.1 Advantages

3.2.2 Disadvantages

3.3 Our Model

4. IMPLEMENTATION

4.1Delta XYZ Axis Movements

4.1.1 Block Diagram of Electronic Setup

4.1.1.1 Controller Unit.

4.1.1.2Stepper driver

4.1.1.3 Stepper Motor

4.1.1.4 Power Supply

4.1.2 Mechanical Setup

4.1.2.1 Components

4.1.2.2 Final Setup

4.2 Firmware Setup

4.3 Writing Tool

5. RESULT & CONCLUSION

5.1 Results

5.1.1 Outcome of the experiment.

5.2 Conclusion

Appendix A

Presentation

REFERENCES

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LIST OF FIGURES

Figure 2.1 Six Wire Stepper motor in unipolar configuration

Figure2.2 Six Wire Stepper Motor in full coil bipolar configuration

Figure 2.3 Six Wire Stepper Motor in Half coil bipolar configuration.

Figure 2.4. Identification Of Common Wire By Resistance Method

Figure 2.5. Four Wire Stepper motor.

Figure 2.6 Connection Of Four Wire Stepper Motor With Driver.

Figure 2.7. 4×4 Matrix Keypad

Figure 2.8. Interfacing Stepper Motor with Arduino Uno.

Figure 3.1 Cartesian and Delta Formation

Figure 4.1 Complete electronic setup

Figure 4.2 Arduino UNO

Figure 4.3 Stepper motor driver

Figure 4.4 Stepper motor

Figure 4.5 SMPS

Figure 4.6 Existing Prototype

Figure 4.7 Our Prototype

Figure 4.8 Wooden blocks

Figure 4.9 Threaded rod (EN-8) with Flange nut

Figure 4.10 Linear Bearing

Figure 4.11 Radial Bearing

Figure 4.12 Smooth rod

Figure 4.13 Shaft Coupler

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Figure 4.14 Final Setup

Figure 4.15 Writing Tool

Figure 5.1 Final Completed Setup

Figure 5.2 Braille dots

Figure 5.3 Presentation

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CHAPTER 1

OVERVIEW

1.1 INTRODUCTION

In the present age of robotics, the focus is on the creation of automatic

version of every activity. Marking Braille dots manually is not efficient. So by

the use of automatic Delta Positioning mechanism , the accuracy of the

embossing process is achieved. In order to fully automate the embossing

process we use the popular Arduino as microcontroller.

Arduino are currently being used in various applications due to its good

ability to communicate in digital form . Specifically in our project it enables

simultaneous movement of the arms based on the given input. The

dimensions of the arms and other parts are carefully determined to match our

requirements for embossing. Also the nature of the materials used for the

threaded rods and the arms are carefully selected to avoid rusting.

1.2 OBJECTIVE OF THIS PROJECT

The objective of this project is to develop an efficient model for the

Braille Embossing mechanism using microcontroller. The Arduino code

effectively functions and the desired accuracy is also achieved.

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CHAPTER 2

BRAILLE EMBOSSER

2.1 Introduction :

A braille embosser is a device that can generate printed material using the

braille writing system for blind or visually impaired users. They press dots

down onto a piece of paper to let a person using the braille system read by using

their fingers. They are a form of assistive technology. A braille embosser is also

known as a braille printer.

Braille printers receive data from computer devices and emboss that information

in braille onto paper through the use of solenoids that control embossing pins.

Braille printers typically print on heavyweight paper and use up more pages for

the same amount of information than pages printed on a regular printer. They

are also slower and noisier. Interpoint printers are braille printers that emboss

braille on both sides of a page.

Braille embossers usually need special braille paper which is thicker and more

expensive than normal paper. Some high-end embossers are capable of printing

on normal paper. Embossers can be either one-sided or two-sided. Duplex

embossing requires lining up the dots so they do not overlap (called "interpoint"

because the points on the other side are placed in between the points on the first

side).

Once one copy of a document has been produced, printing further copies is

often quicker by means of a device called a thermoform, which produces copies

on soft plastic. However the resulting braille is not as easily readable as braille

that has been freshly embossed, in much the same way that a poor-

quality photocopy is not as readable as the original. Hence large publishers do

not generally use thermoforms.

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2.2 SIX WIRE STEPPER MOTOR

Unipolar Configuration

6-wire motors have three wires per phase. Two wire leads connect to either end

of one phase with a third wire connected to the center point between the coils as

shown in Figure 1. This third wire is commonly referred to as the phase's center

tap. To connect the motor for unipolar operation, the six wires are configured

essentially as an H-bridge.

Fig 2.1 6 wire stepper motor in unipolar configuration

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Full Coil Bipolar Configuration There are two methods to connect a 6-wire motor for bipolar operation. The first

method is simply to leave the center tap leads disconnected and connect the

motor as you would a normal 4-wire bipolar stepper motor. This type of

configuration is shown in Figure 2 and is sometimes known as a full coil

configuration as the drive will be energizing the entire coil of each phase.

Fig2.2 6 wire stepper motor in full coil bipolar configuration

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Half Coil Bipolar Configuration It is also possible to connect a 6-wire motor in a bipolar configuration which

only utilizes half of the motor's coils. A full coil setup presents an inductive

load to the motor drive four times greater than the inductance presented by the

half coil arrangement, allowing the motor to operate at much higher speeds.

Fig 2.3 6 wire stepper motor in half coil bipolar configuration

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2.3 Identification of common wire in a stepper motor

Most stepper motors come with four, six, or eight wires. This motor uses six

wires. What we need to do is measure the resistance from one motor wire to

another. This is because of the way stepper motors are made, stepper motors

will have two coils and since this motor has six wires that means there are 3

wires per coil. Each of the two coils will have a common wire attached to the

center of the coil, we don't want to use this wire. The way that we can determine

which wire this is his by measuring resistance, and the resistance from one of

the center wires to one of the other wires on the same coil will be smaller than

the other pairs. If two wires are not on the same coil, you will measure an open

circuit

Fig 2.4 Identification of common wire by resistance method

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2.4 Four Wire Stepper Motor And Interfacing with Arduino

NEMA 17 is a common size used in 3D printers and smaller CNC mills.

Smaller motors find applications in many robotic and animatronic

applications. The larger NEMA frames are common in CNC machines and

industrial applications.

The NEMA numbers define standard faceplate dimensions for mounting the

motor. They do not define the other characteristics of a motor. Two different

NEMA 17 motors may have entirely different electrical or mechanical

properties.

Fig 2.5 Four wire stepper motor

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Connection with Arduino and A3967 driver

The nema 17 is connected with arduino and a3967 driver.

TheEasyDriver is a simple to use stepper motor driver based on an

Allegro A3967 chip. It is compatible with anything that can output a

digital 0 to 5V pulse (or 0 to 3.3V pulse if you solder SJ2 closed on

the EasyDriver). The EasyDriver requires a 6V to 30V supply to

power the motor and can power any voltage of stepper motor. The

EasyDriver has an on board voltage regulator for the digital interface

that can be set to 5V or 3.3V. Connect a 4-wire stepper motor and a

microcontroller and you’ve got precision motor control! EasyDriver

drives bi-polar motors, and motors wired as bi-polar i.e. 4,6, or 8 wire

unipolar stepper motors where the center tap wires are not connected.

Fig 2.6 Connection of 4-wire stepper motor with Arduino UNO

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2.5.Stepper motor with 4x4 matrix keypad

A small extension to the above program was done by including 4x4 matrix

keypad to control the rotation of stepper motor instead of giving the inputs from

computer keyboard as serial input.

Fig 2.7.4*4 Matrix Keypad

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CHAPTER 3

XYZ MOVEMENT

Whenever XYZ axis movements are needed in a project it strikes that 3D

printer already use that mechanism. The difference between this two is different

ways of navigation of the print head through the 3D print space.So we referred

to the types of 3D Printers in the market.

There are generally 2 types of XYZ axis Movements in 3D printers:

Cartesian type

Delta type

Fig 3.1 Cartesian and Delta Formation

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3.1 Cartesian Type

Cartesian printers are named after the Cartesian coordinate system that

uses X, Y, and Z coordinates to plot points. This system of coordinates is used

to determine the location of the print head and the extruder. Cartesian printers

do this through a system of rails which are used to move the print head and the

print bed to position the extruder anywhere in the 3D space.

3.1.1 Advantages

One of the greatest advantages of Cartesian printers is their popularity.

Since Cartesian printers are the most widely used type of printer, there is far

more support for users of these printers than for users of Delta printers. It is

easier to find parts and to repair Cartesian printers because of this solid market.

In addition, prints from a Cartesian printer tend to have a better surface finish

than prints from a Delta printer. This is because Cartesian printers have more

rigid axes, which allow less room for error when the print head moves within

the 3D space.

3.1.2 Disadvantages

The main disadvantage is moving speed. And print bed is moving which

enables for further errors. But overall there are no problems with Cartesian

models.

3.2 Delta Type

Delta printers, like Cartesian printers, also work within the Cartesian

plane. However, they use a different system to navigate and locate the print

head within the 3D space. A delta printer consists of three arms on rails that

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move up and down independently to move the print head. Delta printers use

trigonometric functions based on the angles that these arms create to determine

the precise location of the print head within the 3D print space.

3.2.1 Advantages

Delta printers have circular print beds which gives them a more efficient

use of the printing space, especially when printing circular prints. Additionally,

many of the print beds are non-moving, which can be an advantage for some

prints. One of the main advantages of a Delta printer is its speed. These printers

were designed for quick printing. Delta print heads are built to be as light as

possible, which results in a quicker printing process.

3.2.2 Disadvantages

However, this design focus on speed results in several disadvantages for

the printer. One is the precision of the printer. As the speed of the printer

increases, its precision decreases. Because of this, Delta printers tend to print

with less detail and a rougher surface finish than Cartesian printers.

3.3 Our Model

We decided to go with delta type xyz movement due to its precision at

lower speeds since we don’t need higher speeds and due to the fact that bed

doesn’t move in this type.

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CHAPTER 4

IMPLEMENTATION

4.1 Delta XYZ axis movements

The Movement in each axis should be highly precise and accurate. Only

way to achieve this is to use stepper motors. Stepper motors are special motors

that need an extra driver circuit to operate.

4.1.1 Block Diagram of Electronic setup

The complete system block diagram is shown in the figure 4.1. In the block

diagram, there are Four parts.

(i) Controller (ii) Driver (iii) Motor and (iv) Battery.

Figure 4.1 – Complete electronic setup

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4.1.1.1 Controller Unit

Development boards, such as Arduino and Raspberry Pi, are common

choices when prototyping Robots. These development boards like Raspberry pi

are essentially mini-computers that can connect to and be programmed by a

standard PC or Mac. After it has been programmed, the development boards can

then connect to and control sensors in the field. In our case Arduino suits well.

Arduino UNO

The Arduino UNO is a widely used open-source microcontroller board

based on theATmega328Pmicrocontroller and developed by Arduino.cc

It contains everything needed to support the microcontroller; simply

connect it to a computer with a USB cable or power it with a AC-to-DC

adapter or battery to get started.

The board is equipped with sets of digital and analog input/output (I/O)

pins that may be interfaced to various expansion boards (shields) and

other circuits.

The board features 14 Digital pins and 6 Analog pins.

The Arduino has a large support community and an extensive set of

support libraries and hardware add-on “shields”

It is programmable with the Arduino IDE (Integrated Development

Environment) via a type B USB cable. It can be powered by a USB cable

or by an external 9 volt battery, though it accepts voltages between 7 and

20 volts.

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Fig 4.2 Arduino UNO

4.1.1.2 Stepper Driver

The A3967 is a complete microstepping motor driver with builtin

translator. It is designed to operate bipolar stepper motors in full-,

half-, quarter-, and eighth-step modes, with output drive capability

of 30 V and ±750 mA.

The A3967 includes a fixed off-time current regulator that has the

ability to operate in slow, fast, or mixed current-decay modes. This

current-decay control scheme results in reduced audible motor

noise, increased step accuracy, and reduced power dissipation.

The translator is the key to the easy implementation of the A3967.

By simply inputting one pulse on the STEP input the motor will

take one step (full, half, quarter, or eighth depending on two logic

inputs).

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There are no phase-sequence tables, highfrequency control lines, or

complex interfaces to program. The A3967 interface is an ideal fit

for applications where a complex μP is unavailable or over-

burdened.

Features and Benefits

▪ ±750 mA, 30 V output rating

▪ Satlington sink drivers

▪ Automatic current-decay mode detection/selection

▪ 3.0 to 5.5 V logic supply voltage range

▪ Mixed, fast, and slow current-decay modes

▪ Internal UVLO and thermal shutdown circuitry

▪ Crossover-current protection

Fig 4.3 Stepper motor driver

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4.1.1.3 Stepper Motor

Stepper motors are great motors for position control. They can be found

in desktop printers, plotters, 3d printers, CNC milling machines, and

anything else requiring precise position control.

Steppers are a special segment of brushless motors.

They are purposely built for high-holding torque. This high-holding

torque gives the user the ability to incrementally “step” to the next

position.

This results in a simple positioning system that doesn’t require an

encoder. This makes stepper motor controllers very simple to build and

use.

These stepper motors, in particular, are used with the Shapoko CNC

machine and offer 125 oz.in of torque and 200 steps per revolution.

Additionally, each motor has been equipped with extra long 600mm

AWG22 wires, making them ideal for CNC applications.

Fig 4.4 Stepper motor

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4.1.1.4 Power Supply

Output Voltage: 12VDC

Output Current Range: 0–12.5A

Output Rated Power: 150W

Protections: short circuit, overload, overvoltage

Cooling by free air convection

LED indicator for power on

100% full load burn-in test

Fig 4.5 SMPS

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4.1.2 Mechanical Setup

Mechanical setup is lightly complicated. First we built a single axis.

Fig 4.6 Existing Prototype

Fig 4.7 Our Prototype

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4.1.2.1 Components

Wooden blocks

Fig 4.8 Wooden blocks

Threaded rod(EN-8) with Flange nut

Fig 4.9 Threaded rod(EN-8) with Flange nut

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Linear Bearing

Fig 4.10 Linear Bearing

Radial Bearing

Fig 4.11 Radial Bearing

Smooth rod

Fig 4.12 Smooth rod

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Shaft coupler

Fig 4.13 Shaft coupler

4.1.2.2 Final Setup

We replicated three single axis movements and finally attached together.

Fig 4.14 Final setup

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4.2 Firmware Setup

We used Marlin Firmware to run the delta movements. Delta X, Delta Y,

and Delta Z are calculated by this firmware and the end effector (center object)

is moved to this position by the stepper motors.

4.3 Writing Tool

We tried different types of writing tools like pen , pencil, sketch pen and

crayon. Out of the four above mentioned writing tools we found sketch pen to

be the best possible writing tool for this Braille Embosser. So we fixed a sketch

pen in the triangular base which is junction of the axes.

Fig 4.14 Writing Tool

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CHAPTER 5

RESULT &CONCLUSION

5.1 Results

The XYZ Movements and embossing mechanism were successfully

implemented for our scenario. And firmware is perfectly implemented to find

delta movements. Therefore the writing tool is moved to the corresponding

position with the help of Stepper motors and their drivers by the Arduino

microcontroller.

Fig 5.1 Final completed setup

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5.1.1 Outcome of Experiment

Fig 5.2 Printing Braille characters with writing material attached at the bottom

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5.2 Conclusion

This is technically feasible like any other approach to automatic Braille

embossing mechanism. Since its components are fully indigeneous it can be

replaced easily in case of any problem. And the firmware used is marlin which

is an open source firmware.

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Appendix A

Presentation

Fig 5.3 Presentation

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REFERENCES

[1] Microprocessor Architeture, Programming and Applications with

8085 – Ramesh S Gaonkar

[2] Microprocessor and Interfacing, Programming and Hardware –

Douglas V Hall

[3] The 8051 Microcontroller and Embedded Systems – Muhammad Ali

Mazidi

[4] Arduino : 101 Beginners Guide – Erik Savasgard

[5] https://circuitdigest.com/microcontroller-projects/keypad-interfacing-

with-arduino-uno

[6] https://impremedia.net/arduino-stepper-motor-

wiring/https://www.printspace3d.com/cartesian-vs-delta-printers-

work/

[7] http://www.reprap.org/wiki/Delta_geometry

[8] http://robinsonia.com/wp/?p=161

[9] https://ieeexplore.ieee.org/document/7759338/

[10] https://www.sparkfun.com/

[7]https://forum.arduino.cc/index.php?topic=377364.0

[8]https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://co

eleveld.com/arduino-stepper-a3967-

easystepper/&ved=2ahUKEwjk9oXL5obbAhWHOo8KHQITDY4QFjA

CegQIBBAB&usg=AOvVaw14TzIWmOYCIjMm4qJ9jL-T