Development of portable braille reading sensor system (detection mechanism and design of plate spring holder)

This paper presents a plate spring type sensor for reading Braille. A Braille letter is consisted of 6 dots of 3 times 2 arrays. The sensor detects the height of Braille dots via three plate springs and three strain gages. The proposed sensor detects Braille dots with good accuracy because the plate spring contact Braille dots directly. On the other hand, dots may be damaged by the sensor because of the direct contact. The degree of damage and frictional wear are examined experimentally. Furthermore, a prototype sensor holder, which make possible to scan the plate spring on the surface of Braille letter in one hand, is designed. The holder has a ditch in order to avoid deviation from Braille letters. The outline of a sensor holder is described, and the preferable shape and weight of the holder are discussed.