I actually did film the construction of the device, but there were problems with the camera and the editing, so I decided to not publish the footage.
Here you can see the result of using the device "stand alone", I did not manage to get it working reliably using the midi port, but I may have fudge a couple solders, I'll have to revisit that later.
The device was bought from https://rarewaves.net/products/midi-narrator/
...
https://www.youtube.com/watch?v=PnBsYtFFkPQ