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.
A new development, called the rotating-wheel Braille display, was developed in 2000 by NIST and is still in the process of commercialization. Braille dots are put on the edge of a spinning wheel, and allows the blind user to read continuously with a stationary finger while the wheel spins at a selected speed. The Braille dots are set in a simple scanning-style fashion as the dots on the wheel spins past a stationary actuator that sets the Braille characters. As a result, manufacturing complexity is greatly reduced and rotating-wheel Braille displays will be much more inexpensive than traditional Braille displays.
