[DavidVoid]

This just reminded me of the most unusual switch I've ever heard of: Smith-Corona's acoustic switch from the 80s.

There's no per-switch sensor at all!

Instead, each key-press just results in one wide metal bar being hit. And to figure out which key was pressed, there's a sensor on the right and the left side which are used to calculate what key was pressed based on how long it took for the signal (i.e. vibration in the bar) to reach the left and right sensor.

It's so clever and so ridiculous at the same time!

[1] Video presentation (Talk about acoustic switches starts at 1:46:00): https://youtu.be/AvszDsr1js8?t=6361

[2] Slides: https://docs.google.com/presentation/d/1jfWpf8cABnH54yVjPIU3...

[snori74]

Once dealt with a 2d digitising pad that worked off the audio click of a spark in a similar way. Wild.