[nyc]

The principle behind why the writing glows (i.e., totally internally reflected light from the LEDs in the plexiglass getting scattered by the ink) is also how some of the earlier multi-touch systems worked (like the one in Jeff Han's 2006 TED talk). So, with the right software, it might be possible to convert one of these DIY lightboards to support input (maybe to change slides or something).

[mncharity]

Perhaps use hand tracking[1] to get candidate finger-tip positions, to simplify using the FTIR touch blobs for contact detection and precision position?

[1] https://viz.mediapipe.dev/demo/hand_tracking Web demo - run button is top right.

[oauea]

Or just add a few special purpose physical buttons to the side.