Hi Lee.

Thanks for your comments.

I actually have another project that I wrote that provides a maths interface and a diagram drawing application along the lines you suggest.

I should put it up on the Hackaday site but have never got round to it.

It uses mathjax  https://www.mathjax.org/ javascript stuff to do the equation and symbol display bits and relies on simple (one finger) keystrokes to drive both the maths and diagram drawing interface.

It was initially meant to be the display component for the light pen idea here but it turned out to work better for the intended user with just a keyboard interface.  It initially used a trained neural net to get input from things like the Light Pen but that has since been disabled because as mentioned - for the intended user the keyboard input worked better.

By mapping symbols to widely spaced keyboard letters I avoid the need for 2 key inputs or close accuracy of hitting keys (eg shift = for the minus symbol is replaced by 'p' for plus etc) and it also provides the ability to draw diagrams without using a mouse but by steering "to and from" cursors with keys.

The code for the application is at https://github.com/jonkster/mathscribe 

cheers

Jon

Have you thought about providing a dedicated maths style interface rather than a writing style one?

Take a look at the equation editor within the MS Office packages and that's the sort of thing I was thinking.  Obviously the interface would need to be made a lot chunkier to support the lack of motor skills but then, there is likely a lot of complexity that could be dropped depending on the level of the student.

There are some open source equation editors that you may be able to pick up code from:

https://en.wikipedia.org/wiki/Formula_editor