Thanks for sharing this. This really inspiring stuff - a step away from the norm of taking a PC/laptop and using wsjtx. A true homebrew effort. Your user interface looks great. Presumably the audio input/output is standard audio and this would work with an FT817 etc.?
There is now a fairly confusing amount of micro controller boards/families available for hobbyists. However, the Teensy seems have a lot going for it, good support and a good community. I used it earlier this year and was impressed.
That looks really good, much easier than carrying a tablet PC around.
If you get the chance can you do another video showing a successful QSO to show what the screen shows you? (does it highlight in red and does it autosequence etc.)
This is really interesting for me as I have been tinkering with a Pi 3B and 5 inch touch screen to try and get the package as small as possible. This looks to take it a little further and I have down loaded all the information and am looking at possibly building one but probably to work with a dedicated rock bound digital trx.
My pi vesion and digital trx work well as they are but power consumption of the pi and screen is quite high as I like to do multi day hiking trips and need power to run several evenings or morning sessions.