[BCAB] Braille display question

Michael A. Ray mike.ray at btinternet.com
Sun Feb 3 23:55:36 GMT 2013


Steve,

This is the kind of reverse engineering I like.

I have just had a look at the FS Braille display driver in NVDA and it 
seems to do all of it's communication with the display via a proprietary 
DLL.  Just as you might expect I guess.

You could try hooking the display up to Hyper-Terminal at different 
speeds and see if key-presses get any coherent data to be displayed.

Short of that you could have a go at hacking something from the NVDA 
source code in Python and see what you can divine.

Do you have an RS232 break-out box or some other way of creating a 'T' 
connection between your PC, the Arduino and the display?

And...do you know about my Raspberry Pi mailing list for vi users?

If you would like to join, send an email to:

raspberry-vi-requests at freelists.org

With 'subscribe' in the subject.

Mike


On 03/02/2013 23:32, Steve Crawford wrote:
> I've just acquired a Freedom Scientific Focus 44 braille display and am
> trying to talk to it via its serial port using a microcontroller called an
> Arduino. In other words, I'm not using any drivers, just raw ascii
> characters. Unfortunately I can't find any sort of technical information on
> this, nor any other, braille display. Can anyone out there shed any light on
> the following:-
>
> 1. What sort of commands do I need to send to the display in order to mkae
> it display text? ie something like "HELLO WORLD" - is it a matter of
> inserting some escape sequences before the text or what?
>
> 2. When I press the keys on the unit I get some data coming out of the
> serial port, depending of course on the baud rate. Does anyone know what
> baud rate it is likely to be (my best guess at the moment is either 38k or
> 56k) and do you know what the data should look like?
>
> Many thanks.
>
>

-- 
Michael A. Ray

Analyst/Programmer
Witley, Surrey, South-east UK

Ham Radio Callsign: G4XBF, licenced since 1982

'Entia non sunt multiplicanda praeter necessitatem'

Use the NVDA screen-reader, not Scientific, just Freedom:
http://nvda-project.org/




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