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Brindle: A Low-Cost Refreshable Braille Display with Slider Mechanism

Aroni Ghosh, Toiyob Hossain, Md. Jawad Ul Islam, Mrinmoy Kundu, Nawshad Binta Nizam, Shaikh Anowarul Fattah

Department of EEE, Bangladesh University of Engineering and Technology

Paper ID

128

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Presentation Outline

  • Introduction
    • Background and Motivation
  • Literature Review
  • Design and Functionality
    • Our Proposed Design
    • Working Principle
    • Block Diagram
    • Control Flow
  • Specification Analysis
  • Comparison
  • Future Scopes
  • References

2

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Background and Motivation

  • According to WHO, 285 million people are estimated to be visually impaired worldwide, among which 90% live in developing countries[1].
  • Around 35,000 children in BD are living in blindness, who needs braille for their education
  • Audio books cannot replace the natural feedback.
  • Braille books are expensive and difficult to mass produce like paper books
  • Traditional braille displays are even more expensive.

3

Image Source: archive.dhakatribune

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Literature Review

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Solenoid Actuator[2]

  • High Power Consumption
  • Heavy & Maintenance problems
  • Locking mechanisms required
  • Not portable
  • #actuators = 6

​

​

Piezoelectric Braille Cell[3]

  • Light weight & small in size
  • Too expensive and currently not available in BD
  • Large Power requirement for each character generation
  • #actuators = 6

​

Our Design Goal

  • Cost should be minimized
  • To reduce the number of actuators
  • To reduce form factor
  • Minimum power requirements
  • Easily scalable

6-servo-per Cell[4]

  • Bulky and not portable
  • Over engineered
  • Power consumption high
  • #actuators = 6

​

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Our proposed design

​

​

​

​

5

Total half-cell system

Single Pin

Unit Cell Cap

Half-cell slider-rack and pin system

We break each 6-dotted unit cell into two half-cells along the vertical line, and a unit cell requires in total

  1. Slider and rack : 2 units
  2. Gear and Servo : 2 units
  3. Housing and Cap : 2 units
  4. Pin : 6 units
  5. Servo motors : 2 units

​

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Top View of the Pins

Working Principle of a Half-Cell

​

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  • Each half-cell with 3 vertical dots can produce 23 = 8 different combinations
  • Three pins – standing on the three consecutive hills/valleys materialize a 3-dotted pattern
  • de Bruijn sequence of B(2,3) : 011101000 produces all possible combinations

Half-cell slider-rack and pin system

0 0 1 1 1 0 1 0 0 0

wiecon.ece.org

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

7 of 13

System Block Diagram

7

Angle Encoder Data

Next Character Signal

Previous Character Signal

Servo motors

Each half-cell

Positional Feedback Path

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Control Flow and Assembly

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A complete working device with (1) Micro-controller (2) Button (UI), and (3) Display cell for a character

Control flow of the device

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Performance Analysis

  • Power Consumption

9

  • Dimensions and Form Factor
  • Portability Analysis
  • Response Time

Takes at maximum of 0.3s to change between states.

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

Name of the Part

​

Slider and rack

​

Housing

​

Cap

​

Pin

​

Gear

​

Total Volume =

​

Component Name

Idle Power

Active Power

Arduino-UNO (R3)

50 mA at 9 V

10 mA approx. at 9 V

SG90 Micro Servo

10 mA at 4.8 V

100-250 mA at 4.8 V

Total power per cell

96 mW

2.4 W

Name of the part

Quantity

Weight (gm)

Arduino-UNO (R3)

1

25

SG90 1.5 kg/0.3 s 9g Micro Servo

2

29.4

3D printed half cell

2

80

Total Weight

​

134.4

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2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

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Benchmarking of the design

TABLE : Benchmarking with Different Braille Systems in Literature

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Braille System

Cost ($)

Power (mW )

Dimension (mm³ )

Refresh Time (s)

Piezoelectric [3]

62

145

6.4 x 10 x 67

-

Solenoid actuator [2]

49

1020

250 x 160 x 200

-

Micro Servo [4]

29

558

200 x 100 x 300

1 s

Electrode Array [5]

40

20

20 x 20 x 28

10 s

Electrotactile [6]

19.2

600

500 x 500 x 400

0.1 s

Our design

12

153.6

160 x 82.5 x 80

0.3 s

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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Conclusion

  • $12 per cell - highly cost effective
  • Prototype tested
  • Superior performance in terms of portability, cost-effectiveness, and user-friendliness
  • Potential to be a transformative and empowering tool for the visually impaired
  • Further reduction in form-factor and weight is desired for widespread adoptation

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Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

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References

  1. Bourne, Rupert RA et al. The Lancet Global Health 5.9 (2017): e888-e897.
  2. Kumari, Sangeeta, et al.2020 International Conference for Emerging Technology (INCET). IEEE, 2020.
  3. K. Minatani et al.2014 IEEE 3rd Global Conference on Consumer Electronics (GCCE), 2014, pp. 206-210
  4. Rahman, AM Muntasir, et al. 2018 2nd International Conference on Imaging, Vision & Pattern Recognition (ICIVPR). IEEE, 2018.
  5. Zhou, Ziliang, et al. IEEE/CAA Journal of Automatica Sinica, 2023.
  6. M. M. H. Saikot and K. R. I. Sanim, IEEE Transactions on Haptics, vol. 15, no. 3, pp. 582-591, 2022.

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WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org

Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

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Q & A

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Ghosh et al. Brindle: A low cost refreshable braille display with slider mechanism

WIECON-ECE 2023

2023 IEEE International Women in Engineering (WIE)

Conference on Electrical & Computer Engineering

wiecon-ece.org