Thenar - portable and affordable Braille book

Thenar is the portable electronic Braille book, that was invented to replace >$1000 Braille displays that are available on a market.

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Fully assembled Thenar costs less than $100. This cost reduction is caused by the implementation of two basic concepts:

1. using only one single Braille cell instead of a row of several cells in traditional Braille displays;
2. implementation of a jog-dial for text navigation with a thumb of another hand.

It allowed reducing the cost and weight of the device. But the most significant advantage of this approach is that the device became truly portable. Now a visually impaired person can enjoy reading sitting outside in a park or anywhere else.

Thenar is an evaluation of my previous project of the open-source e-book for visually impaired people.

A quick survey showed that the Braille display is an electromechanical device that can fully replace traditional paper Braille and provides the access to any electronic text. Although there are a great number of speech synthesizers and myriad audiobooks, according to researches the literacy of a person can be developed only by reading. The cool fact is that when a visually impaired person reads Braille, he/she activates the same parts of the brain as a sighted person does.

The heart of the Braille display is a row of several so-called Braille cells, that form a text line. Each Braille cell is a 2×4 matrix of tiny pins moving in and out of the surface forming a Braille character.

 The pins are moved by piezoelectric actuators. Displays have from 10 to 80 cells, and the more cells the better. Hence the frequency of pressing the button decreases making it easier for a reader. 40-cell displays are the most popular. Hence Braille displays have become the only interface for reading nowadays. However, the cost of even 14-cell displays starts from 1000 dollars. In this matter, displays are unaffordable devices for buying for most people.

Another fact is due to the high prices of Braille displays and the lack of updated paper-Braille books the average literacy rate among visually impaired people is lower than 5% even in developed countries. This shocking statistic looks like it describes the Middle ages time.

I love reading. But frankly saying I’m not ready to pay for a Kindle-like device eight or even one thousand dollars. By the way, sliding a reading finger over an 80-character Braille line doesn’t cover an average-length sentence, you will have to press the button to refresh the line and then continue reading.

I decided to work on this issue to make such devices more affordable for visually impaired people and improve their quality of life.

The idea and the first prototype

The first idea in a way to decrease a display price was to define the minimum number of cell in it, and at the same time, this number should be sufficient for comfortable reading (without the constant need to refresh the text line). So I thought it following way:

  1. The boundary values of cell quantity are zero to infinity.
  2. If we have zero cells, a display becomes a text-synthesizer, which is not our goal. That’s why the number of cells should be at list one.
  3. In the case of one cell we get minimal price and minimal comfortability in sliding reading-finger over the Braille-line; in the case of an infinite number of cells, we get maximum comfortability as well as a price.
  4. So the obvious solution is to connect the ends of that long text line to form a circle and let a reader slide his finger around the outer surface of the ring.
  5. This solution has two problems: sliding a finger around a ring is not comfortable, and it still needs to be refreshed by pressing a button.
  6. We have one more initial condition: reading-finger can read (feel/recognize) only on character at the time.
  7. I decided to combine and rearrange these processes, and then divided them between two hands.
  8. Finally, we get the following: reading-finger lay on a sole Braille-cell, sliding around a ring was replaced by rotating a jog dial with the finger of another hand. Refreshment of the Braille character happens with each step revolution of the jog dial.
  9. This approach provides full control of the text stream (forward and backward), and the most important – gives the feeling of reading the endless text-line. To be honest, the last statement I perceived long after.
  10. In addition, the new device needs the following minimal features:
  • Braille trainer;
  • Saving and reading books from SD-card;
  • Voice and Vibro menu;
  • Rechargeable battery;

Having this idea I started making a prototype. The next problem I faced was to find the Braille-cell module. Unfortunately, my search for that modules was unsuccessful. So as a temporary solution, I decided to make my own Braille-cell from electromagnetic relays. The cell...

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View all 55 files

  • 1 × HIPS filament Filament for 3D printing
  • 1 × Arduino Nano
  • 1 × Piezoelectric Braille Cell P11 Braille Cell by Metec-AG
  • 1 × DC-DC converter 200V 5V to 200V DC-DC boost-up converter
  • 10 × M3 Bolts

View all 22 components

  • 1
    List of equipments and tools you need to make Thenar.
    1. hot glue gun
    2. paint brushes (1” and 3”)
    3. screwdriver set
    4. Arduino
    5. soldering iron
    6. wire cutter
    7. digital multimeter
    8. metal file(s)
    9. sanding block
    10. 3D printer
    11. tool box
  • 2

    It is better to print models from HIPS filament. It is not expensive and very handy for sanding.

    Prefer to choose dark colors of filament - it will be easier to see where on a surface you need to sand more. Best choice is black color.

    Same is for color of UV resin for 3d printing - it is better for curing.

  • 3
    Printing parts

    Print all of the parts in the package. For your convenience, they should be printed in one piece. Place all the models on a print bed so that supports will not connect to the outer surface of the case. It is enough to print parts with 0.2 mm thin layers with 30% infill of filament. Except for Braille pins and a pin cap are printed on an FDM (FFF) 3d Printer.

View all 12 instructions

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Joseph Summerville wrote 01/27/2023 at 15:28 point

A very interesting and much needed project, I would like to check it out to understand how it works. Once I had a similar experience during my studies, I wrote an essay about crime and having found a similar work on I also tried the text of the adventures and a book on this text Braille. I learned how to read them a long time ago, so there were no problems with it, but after a long time without practice I need to return the skills and maybe I'll take myself a similar device. 

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heinz wrote 11/08/2021 at 15:17 point

Nice read, great project!

The piezo braile cell is interesting and only 30$. 

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A.dzhusupov wrote 11/08/2021 at 15:27 point

Yes, I was reallly happy to find supplier of Braille Cells. Previously, I made them by myself, and they were unreliable. However, they had couple advantage: they were cheeper than $10, and they needed only 5V for operating, unlike Braille Cells with 180V power consumption.

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Shervin Emami wrote 09/27/2021 at 22:47 point

Wow this looks like a great project, well done! I hope it progresses well!

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A.dzhusupov wrote 11/08/2021 at 05:36 point

Thank you for your support!

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