Back in September, I had the pleasure of sitting with Greg Priest-Dorman at ISWC/UBICOMP for a while. A 19+ year veteran of chording, Greg has a lot of insight into this field. He suggested that the Twiddler would be a great device for people who already know Braille. The Twiddler has enough keys and can easily be configured to represent the entire Braille alphabet and numbers. The learning curve would be almost non-existent as it is close to 1:1 representation of the Braille Cell.
So here is the 1st variant of the Braille config.
Braille_v1_twiddler.cfg (266 Bytes)
The Braille Cell is composed of 2 columns and 3 rows.
The Braille Cell on the Twiddler is outlined here.
If you hold the Twiddler with the keys facing you, Dot 1 is at the top left (L000 in Twiddler notation) and Dot 6 is in the middle column of row 3 (00M0). The right column is used to indicate that both dots are active in the row. More about this later on...
Standard Twiddler Chord Notation is outlined here: http://twiddler.tekgear.com/doc/doku.php?id=chordnotation
So, to type the letter "a" just type L000.
Dot 1 = L000
The Twiddler does not support multiple keypresses in a row but Braille uses these all the time. In these cases just use the key in the right most column of the corresponding row to indicate double press. It is shown as 1/4, 2/5 and 4/6 in the image.
So, to type the letter "d" just type RM00.
Dot 1,4, and 5 = RM00
Capitalizing is handled through the Shift Button on the top right, beside the joystick, of the Twiddler. Just hold down Shift and type the lower case letter.
Numbers in Braille are preceded by a "#". For the Twiddler, just hold the Num Button, located at the top left, beside the joystick, of the Twiddler.
Contractions in Braille are also available on the Twiddler. Just try "for", "and", "the", "ing" and "ed".
This particular twiddler config variant maps the Braille Cell oriented as the user is looking at the keys of the Twiddler. While the Twiddler is normally used with the keys pointing away from you, this mapping felt like the most natural and easiest to understand.
Please give it a try and provide some feedback. We can work on a mirrored version, or other versions if you want to try something else out.