[ge96]

What about those beam breaker strips you could put on x/y axis, maybe multi-touch/item placement would be problematic.

[snide]

Yep. That's what IR frames do, and that's exactly the problem. What I've built actually works really well, it's just hard to justify that pricing.

[pjc50]

Long ago I did semiconductor work for https://www.flatfrog.com/flatfrog-board , which uses the beam principle combined with in-surface refraction, and I see they're still pretty expensive. You do get an awful lot of little DSPs around the edge for that price, though.

[ge96]

I wonder if you had a big table maybe you could use a camera looking upwards and see the dark spots covering the board that's semi-transparent.