[tabi] Braille Displays Promise to Deliver the Web

  • From: "Lynn Evans" <evans-lynn@xxxxxxxxxxx>
  • To: <tabi@xxxxxxxxxxxxx>, <VICUG-L@xxxxxxxxxxxxxxxxxx>
  • Date: Wed, 7 Apr 2010 11:20:06 -0400

from the web site, 

-  April 5, 2010
Braille Displays Promise to Deliver the Web to the Blind
North Carolina State University researchers take the first steps toward making 
an affordable and more dynamic Braille display
By Larry Greenemeier 

The Web's wealth of information would lose some of its luster if you read it 
only one line at a time. Yet this is exactly how blind and other 
vision-impaired people today must experience the Web when they use electronic 
Braille displays connected to their computers.

Braille displays use electromechanically controlled pins, as opposed to the 
lights in a conventional computer monitor, to convey information. Here is how: 
Software gathers a Web page's content from the computer's operating system, 
converts the words and images into a digital version of Braille and then 
represents that via a touchable row of finger-sized rectangular cells lined up 
side by side like dominoes. Each cell has six or eight small holes through 
which rounded pins can extend and retract with the help of piezoelectric 
ceramic actuators to represent various Braille characters. Each time a person 
reads the row of Braille with his fingers (left to right), the pin 
configurations refresh to represent the next line of a Web page's text, and so 

Breaking Braille barriers
Efforts to improve Web pages translated into Braille have progressed slowly 
because of the cost and complexity of Braille displays, but a team of North 
Carolina State University researchers in Raleigh has taken the first steps 
toward developing a device that would allow the blind to take better advantage 
of the Web and other computer applications. Instead of presenting electronic 
content one line at a time, this display would translate words and images into 
tactile displays consisting of up to 25 rows, each with 40 cells side by side. 
Braille readers would have multiple lines of text and numbers at their 
fingertips, enabling them to backtrack and review content more easily. Another 
possibility might be to present in Braille equations and other information that 
take up more than one line at a time.

"It's difficult to achieve any spatial recognition with just a single line," 
says Neil Di Spigna, a research assistant professor in N.C. State's Department 
of Electrical and Computer Engineering who is working on the project.

The use of piezoelectric ceramic to make a Braille display with multiple rows 
would make already pricey displays even more expensive-low-end models with a 
single row already cost upwards of $1,000. In addition, the amount of energy 
needed to power multiple rows would make these displays bigger, heavier and 
less portable.

Touch and go
The N.C. State researchers are experimenting with two different approaches they 
hope will cut the costs and energy requirements of Braille displays in the 
future, and presented their latest research at the International Conference on 
Electroactive Polymer Actuators and Devices in San Diego last month.

The first approach would rely on hydraulic pressure to raise and lower each of 
the pins in a cell. In this scenario, each pin would sit in a fluid-filled 
plastic case. A window would be cut into the case and covered with a 
polyvinylidene fluoride (PVDF) film. When electricity is applied to the cell 
the PVDF would bend in and squeeze the case through that window, raising the 
level of the fluid and the pin along with it. The researchers say they have 
demonstrated a proof-of-concept prototype that, when less than 1,000 volts were 
applied, got the case to contract and push a fluid consisting of deionized 
water and food dye up so that a pin would rise more than 0.5 millimeters-the 
standard height of a Braille dot-in less than 100 milliseconds (initial 
experiments have been done without a pin in the case).

This is the kind of speed performance a Braille user would expect, says Peichun 
Yang, a postdoctoral research associate in N.C. State's Department of 
Electrical and Computer Engineering who is also working on the project. Yang, 
who is blind, adds that he and his colleagues, including project director Paul 
Franzon, have gotten the fluid to move in 30 milliseconds in some trials. Their 
next step is to create a latching mechanism within the case that would hold a 
pin in place until it needs to be lowered.

The second approach being considered would place each pin in a cylindrical 
silicon tube that raises the pin up when the tube is filled with a conductive 
solution of calcium chloride and 8.75 kilovolts are applied.

The standard piezoelectric approach to making a Braille display costs about $35 
per cell, according to Yang, who adds that this cost needs to be brought down 
to $5 per cell for the displays to be affordable to a greater number of 
consumers. The researchers say that more widespread adoption of Braille 
displays will depend largely on cost, which was an important factor behind 
their research.

Currently, Freedom Scientific, Inc., in Saint Petersburg, Fla., makes several 
different computer Braille displays whose cells are laid out in the standard 
single-row configuration. The company's portable PAC Mate Braille display is 
offered in a single row consisting of 20 or 40 cells, with displays costing 
about $1,600 and $3,600, respectively. Freedom Scientific's larger Focus 
displays include 40- and 80-cell single-row models, which cost about $3,900 and 
$7,800, respectively.

Other approaches
The National Institute of Standards and Technology (NIST) recognized the cost 
problem a decade ago, when an 80-cell Braille display cost about $15,000. Since 
then, NIST has for several years been working on a display with a much 
different design, putting the Braille text on the outside of a spinning 
cylinder like the tread on a tire (pdf). The actuators that move the pins in 
and out are located inside the cylinder. Instead of moving fingers over a 
motionless line of text, the NIST design has the user put one or more fingers 
against the wheel, with the Braille text moving underneath the finger, 
producing a sensation of motion, which the agency claimed provided stimulus for 
the sensors in the fingertips and allowed the user to construct a mental model 
of the geometric layout of the text. The user could also adjust the speed of 
the wheel's rotation.

Speech synthesizer software that can read the contents of the Web or other 
computer text to the blind is an alternative and has the advantage of being 
easier to learn than Braille. Still, as NIST notes in its research, Braille has 
other advantages, enabling "high-precision communication" and the ability to 
read in noisy surroundings.

Speech synthesizers do have a role in helping the blind experience the Web, 
Yang agrees, but the ability to read Braille is essential. "Reading Braille is 
still very important for [blind people] who wish to work-90 percent of blind 
people who hold a job are able to read Braille," he says, adding that 
synthesizer technology is one of the reasons why only 10 percent of blind 
children are learning to read Braille.

N.C. State's work is still in its early days, so do not expect to see their 
Braille display technology at the local computer story in the immediate future. 
It could take the researchers as long as a year just to develop a reliable 
latching system to keep the pins in place. Only then would they be able to make 
an actual Braille display. After that, it could be at least four years to make 
a commercial product, Di Spigna says

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