The Society of Convergence Knowledge Transactions ISSN:2287-8920(Print) 융복합지식학회논문지

The visually impaired prefer a touch-type smartphone, but cannot use it because it is difficult to recognize the key position on the virtual keypad on the touch screen. To improve this, this paper implements a physical keypad module that can be attached to a touch- type smartphone, which is similar to a foldable smartphones familiar to the visually impaired. The implemented system attaches the physical keypad module to the front surface of the touch-type smartphone, and connects them with each other with a USB cable, and key input is received through the physical keypad module rather than the touch screen. The physical keypad module consists of a 4*5 matrix structure keypad, MCU, and a C-type USB connector. The key input through the keypad by the visually impaired is converted into HID format and delivered to the service app of the touch-type smartphone. Key arrangement of the 4*5 keypad is composed of the 4*4 ‘Cheonjiin’ key arrangement applied to foldable smartphones that are familiar to the visually impaired, and 4 functional keys. 4 functional keys are the ‘up/down’ key, ‘OK’ key, and shortcut key, which are often used to facilitate Internet access. By applying the implemented USB keypad module to various touch-type smartphone, it is expected that the smartphone accessibility for the visually impaired will be improved.