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Smart phones have become an important part of our life. These are not just communication devices, yet, they now allow us to store and manage important data, like contacts and personal notes. This requires appropriate input method to input data. However, this task is visually demanding both considering the keypad layout and the screen output. This made it inconsistent with blind user’s capabilities because such tasks need a high visual and cognitive load. As a consequence, many visually impaired users can’t use a smart phone even for simple tasks like making or receiving a call. The worst could be writing an SMS or a text. There is no specific information available about inputs (letters, numbers or special characters) or any of the inputs displacement on the keypad. Screen readers partially deal with this problem by reading the information on the screen. However, the feedback offered is restricted to the output as no information is obtained on input displacement. This approach forces the user to try to find the desired letter committing several errors in the process, possibly leading to situations where the user simply quits trying.
Smooth surface of mobile devices brought up the challenges of difficult access for the blind. In phones with Physical buttons, users feel the buttons and over time they will learn buttons' locations and later they will be able to interact with devices without looking. The touch screen mobile phones create more difficulty for visually impaired people due to none existence of the physical buttons. This fact greatly increases the demand of vision in order to run this kind of mobile.
The device feedbacks tell the users if their action was sensed, and also whether their entered text was accurate. Sighted people simply look at the device and get the feedback, but blind and visually impaired people can only get sensory feedback through their hearing and tactile sense.
Blind people, who are using technologies that support touch based technologies, are having difficulties to memorize the locations of all letters, numbers and special characters. In addition to that, smart phones are having variant sizes, which means that the touch keyboard layout differ from one smart phone to another. This again will make it more difficult for visually impaired people. In fact, small keyboard layout is difficult to use even for normal people.
Other problems, smart phones have small size of buttons and each button is about 0.2 inches, where the size of a normal finger tip is about 0.3-0.4. This means that a finger can cover two or three buttons, and this requires higher accuracy and results in lower speed. Also there is no feedback to tell the users if their action was sensed except through text to speech and many android phones do not support Arabic text to speech (Ghodosi et al. 2011).
Braille language is a language meant for visually impaired people to help them to read and write. It is usually written with embossed paper. Each character is represented in 6 dots arranged in a rectangular. Each dot is called a cell. The number of the used cells and their positions differ from one character to another. Figure 1 shows some English characters written in Braille language.
Arabic language consists of 28 letters, these letters are used to write words and sentences, punctuation marks are also used. Arabic Language is written from right to left. Arabic Braille language provides 28 different codes that correspond to the Arabic alphabetical letters; it also supports numbers and punctuation marks. Our research is concerned with development of a system that can deal with Arab visually impaired users to be able to write text on smart mobile phones using Braille language. Figure 2 shows some Arabic characters written in Braille language.