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Thread: Backspace and delete previous character?

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Posted: 2017-01-04 23:58

I have a friend who had a stroke a year ago. She is now unable to speak and is almost totally paralyzed. But she can move her head and eyes, and has some control over her right hand.

I'd like to teach her to use Morse Code and then to use your program to type messages. For this purpose, she needs to be able to backspace to correct her errors.

Is it possible to create a Morse-Code-like key sequence that she could use to backspace and erase a previous character?

Thanks much.

Posted: 2017-01-05 13:02
The sequence of eight dots is defined as "error" and could be used. I'm not sure whether it's normally used to delete the last character, or the current word. Maybe those with more experience could clarify this, but for your friend;s purpose it could be either, but eight dots would be really slow.

Another thought is eye-tracking. I saw a demo maybe fifteen years ago and was surprised at how accurately the system was, and it was reasonably fast too. You simply looked at (from memory) an on-screen keyboard, and if you paused your gaze on a key for more than a certain time, this was interpreted as a keypress. There are lots of videos related to eyetracking and the disabled on YouTube.

Of course, if you did use morse, you could easily use some unusual sequence to specific meanings, like her own version of the Q code, which would minimize the number of character for a set of common phrases.


Posted: 2017-01-06 01:25

Thanks for your reply.

An eye-tracker or other special gear isn't in the picture, as my friend is on Medicaid. (Google did find a freeware head-tracking app that needs only a laptop and a webcam --no mouse-- but the app is balky and unreliable.)

If I can craft a freeware setup whose hardware consists solely of an old laptop and a mouse, then many other lower-income patients might also benefit. This would be cheaper, and would also be consistent with the KISS principle (Keep It Simple, Sam).

I wonder if an overlong dah (daaaaaah) could be made to serve as a backspace code. If so, then the only other mod needed would be the ability to delete the most recently displayed character.

Posted: 2017-01-13 14:42
Hi Roy,

I'll check what can be done this weekend. I think a very long dash should be easy to implement as backspace. Although it's not "standard", I guess it makes sense in this case.


Posted: 2017-01-13 16:27
Of course a personal agreement will do, may be a long dash or the more usual wide spaced two characters i, or a question mark (vectorized IMI).

Realize that a stroke usually is accompanied with aphasia, that means that you can't express your thoughts in words. Or even worse spell them out in characters.

So my wife and I can order each other a cup of coffee, or whatever, just by winking in Morse code, but both of us know that it will probably not work after a stroke striking one of us.

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