2004 Conference Proceedings

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Seongil Lee
Sungkyunkwan University
300 Chunchun-Dong, Jang-Gu
Suwon, Gyonggi-Do, South Korea
Email: silee@yurim.skku.ac.kr


While the PDA so far has been used mainly by non-disabled users, there are ample opportunities for disabled users to utilize PDAs to perform tasks related to information and web services with simple modification to the PDA and its I/O devices.

In this paper, we are concerned with the accessibility of user interfaces of PDAs and adopted a novel approach in providing modular I/O devices for disabled users so that they do not have to depend on Braille-based note-takers. The most severe disadvantage of the current Braille-based notetakers is its pricing compared to less expensive PDAs. The other disadvantage is that the notetakers are just for those who are well acquainted with and thus mainly use Braille characters. While the portion of those who use Braille among blind population is only less than 10%, it seems worthwhile to make less expensive and light PDAs accessible and usable to blind users who do not use Braille or use Braille and text together. We took the following approach :

  1. Design of portable input device
  2. Design of a hooking program to seamlessly convert Braille input to texts in any application program
  3. Design of multimodal output module


Relatively few studies tried to utilize existing PDA to provide information to the blind users. There are a few problems to this approach in that with relatively big TTS library for the memory equipped on most PDA's, it is hard to process voice synthesizing functions, and that there is practically no way for Braille input and output available with current PDA platforms.

For use of many small portable electronic products, chord keyboards have been proposed as input devices. Since chord keyboards require a small number of keys, they do not need large space different from regular keyboards such as the QWERTY keyboard. In chord keyboards, the user presses multiple key combinations to enter an input instead of using one key for each character. General Braille writers, a typical chord keyboard, have a keyboard of only six keys and a space bar for all Braille characters. These keys can be pushed one at a time or together at the same time to represent Braille symbols for visually impaired people.


3.1 Input Device: Chording Gloves
A pair of Braille-based chord glove was proposed and developed by a research team at Sungkyunkwan University, Korea. Glove-based input is ideal for Braille character input for its natural interface using thumb and the remaining fingers. Since the thumb of each hand can interact with the other fingers simultaneously, different types of contacts can generate several Braille codes.

Each glove has three Braille character keys on the parts of fingertips and four function keys on the middle parts of fingers on the palm side. Three keys on the fingertips of each glove correspond to three dots in a Braille code. Other three keys perform the same function of the space bar, backspace bar, and the carriage return or enter key.

3.2 Braille-to-Text Conversion Program
The chord gloves are originally proposed and developed for the purpose of providing a way for blind users to input data directly to computers or small electronic devices such as PDAs. An obstacle for the blind users to use commercial products would be the lack of Braille-text conversion program for general applications embedded in the products. Key to successful use of the Braille-based input system may be provision of such conversion program in the products so that blind users can store and retrieve data using just the Braille coding system. A conversion program was developed to convert the Braille-based input from the chording glove to texts. It works seamlessly and display the converted text on the screen as soon as the Braille code becomes a complete text word.

3.3 Multimodal Output
In the developed system, multimodal output is generated upon users' selection of modality: visual output through the PDA's LCD screen, voice synthesis using TTS library, and a tactile Braille display being developed as an attachable and portable module.

A voice synthesis program was developed in connection with the Braille-to-Text conversion program using the L&H TTS library. The library was modified for Windows CE environment, generated a voice sound of relatively a good quality.

A tactile Braille display module was developed by our research team using combination of piezoelectric and electroactive polymers. Currently a prototype module with 6 Braille cells with USB connection adapter is under test for better recognition performance. Blind user can get a feedback for what s/he typed using the chord gloves with a voice or Braille output after making entry of each word.


Since the chord gloves developed here use two hands to make inputs instead of one hand, it has some advantages over one hand chord keyboard. the Braille codes for many languages in the world and special symbols including mathematics and music notations have been already defined, it does not need to design new keymap for using this chord gloves. Furthermore, the blind people who have used a Braille keyboard can use the chord gloves without almost no learning. Its interface is much more natural for Braille input and it can be fast and error-free. The chord gloves have clear space advantages over both a regular keyboard and a chord keyboard. In order to develop the keymap for the chord keyboard, either a strong spatial correspondence to the visual shape of the typed character has been used or strong link to a well-built semantic knowledge base has been created. The keymap for our Braille-based chord gloves resembles the grade 2 Braille, which is quite simple and easy to learn because of its natural interface.

Current system will be developed further to be used as a Braille input device for regular mobile computers such as PDAs. Appropriate Braille-text encoding system is also being developed for such a use, so that blind people can make input to various applications of the PDA using the Braille and check the data using Braille or voice outputs.


  1. Gopher, D., Raij, D.: Typing With a Two-Hand Chord Keyboard: Will the QWERTY Become Obsolete? IEEE Trans. On Systems, Man, and Cybernetics, 18(4) (1988) 601-609.

  2. Porosnak, K. M.: Keys and Keyboards. In: Helander, M. (ed.): Handbook of Human-Computer Interaction, Elsevier, New York (1988) 475-494.

  3. Rosenberg and Slater, M.: The Chording Glove: A Glove-Based Text Input Device. IEEE Trans. On Systems, Man, and Cybernetics-Part C: Applications and Reviews, 29(2) (1999) 186-191.

  4. Sturman, D., Zeltzer, D.: A Survey of Glove-based Input. IEEE Computer Graphics & Applications, Jan (1994) 30-39.

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