Task Description refreshable Braille-Display

Background

The tactile Braille writing system is one of the most important ways for visually impaired people to read and write texts and therefore are essential for participation. The Braille lettering is a coded language, that displays each letter, number or other character in a 6-point form (8-point for Computerbraille). It is both used on embossed paper or on refreshable Braille displays. These refreshable displays are essential for the use of digital devices. Current braille displays often show only a single line, which is equivalent to reading black-print on a calculator display. Therefore, research continues to find ways to display many Braille cells on devices with limited installation space.
The Institute of Mechatronics in Mechanics would like to conduct research on actuators, that can be used for Braille cells with small installation spaces. Innovative kinematic and solutions with corresponding actuators are required to fullfill the needs of this application.

Fig. 1: Braille text on paper                  Fig. 2: Refreshable braille display

Task Description

A reconfigurable Braille cell (6 pins) is to be designed. The Braille cell should be able to display dynamically all characters shown in the Braille board in Fig. 4. There are no rules for the actuators used, but it has to be limited to a package volume of 1500 cm³. The cell dimensions from Fig. 3 should be realizable, i.e. the distance between the individual pins. Additionally the display should have a sensor (e.g. push-button) to confirm the Braille-output.

The Braille cell is supposed to be useable for cash or ticket machine buttons as in these examples:

specifications:

• max. size and position of pins according to Fig. 3 (Mitteldruck nach DIN 32976:2007-08)
• max. volume 1500 cm³
• portable
• min. actualization frequency 0.5 Hz
• if you were to buy the components, the cost should be below 100€
• Safe operation (e.g. no toxic chemicals, harmful mechanical parts)
• the materials should be sustainable
• the device should be mass-producable

The system should run with a 3.3V power source (two battery cells) and operate as energy-efficient as possible. If possible, the Braille-cell should allow stacking of similar cells in reading direction. The signal-input will be a byte representing the 6 pins. The control unit should operate the actuators accordingly.

The delivered design should be a mechanical, electronic and software design and proof of concept in Matlab/Simulink-simscape.

Fig. 3: Braille dimensions               Fig. 4: Braille alphabet