[ebalit]

There was a HackadayPrize 2023 competitor that worked on this [0]. He had to rethink the way those devices are built to bring the cost down.

That would be interesting to know if his solution could match the 4k$ in term of usability or if there is some issue like refreshing rate that make the piezo based system necessary for a good user experience.

[0] https://www.youtube.com/watch?v=BXi1tG78AW4

[K0balt]

That looks like a great project. I share your curiousity regarding the user experience of this vs the piezo units. Looking at it, it should be in the 50-100mS range for refresh times, maybe that is too slow? It seems like it would be plenty fast? I wonder if there are other haptic factors with the piezo, like vibration?