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In the 1980s a company called Quotron developed a contactless keyboard. The main circuit board contained a bunch of LEDs and some sort of photo diodes or photo
by litoE 1mo ago
In the 1980s a company called Quotron developed a contactless keyboard. The main circuit board contained a bunch of LEDs and some sort of photo diodes or photo cells, all arranged in a grid. The keys were simply plungers that when pressed down interrupted the light beams shining into some of the receivers. The firmware then decided which key had been pressed and generated the appropriate code. The keyboard itself was huge. Us software people used to joke that, in a pinch, it could be used as a surfboard.
One of the advantages was that you could pour a cup of coffee into the keyboard and it would just keep working.
- ebastler 1mo agoOptical keyboards are still around (although rare) and usually use some variation of Cherry MC style switches without contact pins. Newer tech also consists of magnetic designs (hall effect, tunnelmagnetoresistance or inductive). These all allow for analog input (variable user-settable actuation points for example) which makes them popular with the gaming crowd. I'm developing such a PCB for a different project at the moment. As far as I'm aware none of these are waterproof, however, as they all have exposed PCBs inside the case. I guess one could just conformally coat the circuit board, but I haven't seen that done yet for a commercial keyboard.