During 1991 an idea was developed to produce a braille display 
which would be small in size and simple in construction. It is based 
on the idea that reverses the role of the finger and braille cells. 
To read braille, the person keeps the finger at rest and the braille 
moves beneath it. During late 1991 and early 1992, two visits were made 
to the Governor Morehead School for the Blind and the North Carolina 
Rehabilitation Center for the Blind both in Raleigh, North Carolina
to obtain information as to how the blind read braille and to obtain 
characteristics of a good refreshable braille display. 

	During 1992 and 1993 a prototype computer-aided braille display 
was built by X. Yong Lu as a masters degree thesis in Applied Physics. 
This braille display is shown below.
 Prototype Braille Display

It contains two large braille cells located opposite each other on a 
small disk. Below the disk are six solenoids which raise the braille 
pins. While the disk rotates half a revolution, the finger reads the 
braille content. At the other end of the disk, there is a piece of metal 
that rakes the pins to the reset position. During the second half of the 
disks rotation, the braille cell pins are reset and that cell is positioned 
on top of the solenoids to be programmed with the new braille character 
by the solenoids. 

	The braille cell display is connected to a PC parallel port and
the ASCII string is converted to grade level one braille. The braille pin
information is amplified and drives each solenoid. The display has two
controls, one to repeat the braille characters and the other to control
the speed of the disk. With two braille cells on the disk, the maximum 
reading speed is 54 characters per minute.


	During the Fall 1996 Bruce Stancell began working on an improved 
Braille Display for his master's thesis. His emphasis is to make it 
portable, reduce the braille cells to the standard size and incorporate 
a floppy disk so that it can be a stand-alone instrument. It will still 
have the feature of being used with a PC parallel port. 

	During the first week in March 1997 a demonstration of the 
prototype Braille Display and some features of the portable braille 
display were demonstrated at the American Printing House in Louisville, 
KY. Mr. Stansell researched the size of the disk and the number of cells
on the disk. After making several paper  models and having several blind 
students at the North Carolina Rehabilitation Center for the Blind try the 
disks it was decided to build a four inch (100 mm) disk with 30 braille 
cells located on a radius of 3 inches (75 mm.) Six selenoids were used to
push up the braille pins and their actuation was controlled by two encoder 
wheels and an 8051 microcontroller. It took half a diameter of rotaton to 
produce a braille cell so there were 15 cells available for reading. 
Students who tried this method, thought that the braille was a long straight 
line of cells and never envisioned the rotation. The braille cell size was 
the standard braille book size. The reading speed of this device is 150 cells
per minute or 30 words per minute. 

	In 1999 Christoper Tullar began to develop a mechanical linear 
display using some of the ideas of Mr. Stansell's device. He developed a 
40 cell display that was very simple to use. It was finished late in 2001 
and was taken to the NC Rehabilitation Center for trial. Each of the seven 
students who used the linear refrehable display either wanted to purchase 
one immediately or thought it was a great reading device. The device is 
activated by the user and reads grade level one braille at the speed of up 
to 1000 cells per minute or 200 words per minute.

	Now we wish to make each of the devices a stand-alone unit with 
either a self-contained floppy disk or CD ROM drive. Presently each uses a
PC to download an ASCII output from a word processor.          


	Work on the portable braille display continues...

							020904