[BRLTTY] Using BRLTTY with touch screen input?

[Rich Morin]

Summary

I have some persistent notions about adding touch screen input (TSI) to Linux-based cell phones.  The motivation is to provide cheap, portable, and flexible communication and computing power to blind and visually impaired users.  I'd like some clues about whether and how to use BRLTTY as part of the stack.

Discussion

I gather that BRLTTY can accept braille input and feed it to the Linux console and that it also has some screen review and speech output capability.  Assuming that another subsystem is capable of detecting touch screen input, here are some obvious (if naive) questions:

- Is BRLTTY ever used with input-only devices (e.g., braille keyboards)?
- Is the speech output adequate to support convenient user interaction?
- What BRLTTY interface(s) would be the best (e.g., easiest) to use?
- What data formats does BRLTTY accept (e.g., ASCII, Braille, Unicode)?
- Is there a preferred software interface for control functions?
- What other software subsystems should I consider incorporating? 

The lowest level user interface I have in mind for the device would be the Linux console.  Ideally, it would support a variety of higher-level programs.

The Stack

Here is a terse summary of the sort of stack I have in mind...

Hardware - Several billion Android cell phones have been sold.  Many of these cannot run current versions of Android.  So, they are cheaply and readily available.

OS - There are several Linux variants which run on cell phones.  postmarketOS, based on Alpine Linux, concentrates on older Android devices.

TSI - This subsystem would be structured as a graph of lightweight processes (i.e., Actors) and implemented using Elixir and assorted libraries.

BRLTTY - This would accept input, hand it off to the console, and provide user feedback in the form of generated speech.

??? - higher-level programs (e.g., menu systems, note takers, shells, terminal switches, text editors)

Comments?  Clues?  Suggestions?

-r