Fingers Do the Reading
From: Technology Review - March / April, 2000 - page 20

Computers are just as important to people who are blind as they are to the
rest of us. But current systems of translating screen displays into the
raised dot letters of the Braille alphabet are pretty clumsy: They require
nearly 500 moving parts called actuators to display entire pages at a time. 
Now comes a device, invented by John Roberts and colleagues at the National
Institute of Standards and Technology (NIST) in Gaithersburg, MD, that uses
as few as three moving parts.  

A stream of Braille letters formed along the edge of a rotating wheel is the
basis for the new display. Each turn of the wheel presents a new line of
Braille text. Fingers held just above the rotating wheel read the dots as
they go by. A commercial Braille wheel using this design could be about the
size of a portable CD player and much cheaper than current displays. Software
has been written for the wheel to display scrolling text from electronic
books.  

Caption: Scrolling Braille, simply.

http://www.eetimes.com/story/OEG19990929S0013
http://www.nist.gov/public_affairs/gallery/braille.htm
http://www.nist.gov/itl/div895/isis/projects/Braille/