Refreshable braille display

A refreshable braille display is an electro-mechanical device for displaying Braille characters, usually by means of raising the dots through holes in a flat surface. Because of the complexity of producing a reliable display that will cope with daily wear and tear these displays are expensive, so only 40 or 80 braille cells are usually displayed. On some models the position of the cursor is represented by vibrating the dots, and some models have a switch associated with each cell to move the cursor to that cell directly.