So, what's a "modulable keyfeel" switch? Well, the definition of modulation is, literally, the exertion of a modifying or controlling influence on something. When we think on a normal switch, we mostly find mechanical features that delimitate a certain type of feel, that feel is an inherent atribute of the mechanism that can't be altered without any modification to the estructure of the piece, which represents quite a problem if you want to personalize your key feedback. A modulable keyfeel switch is the absolute opposite, of course, it has a mechanical nature, but the operation of it fuctions based on a phenomenon alien to its own mechanical propperties.
Enough stupid talk, let's release Cthulhu!
This cursed thing has a total of 9 parts, consisting on two housing parts, a slider, two magnets, an infrared LED, an infrared sensor and two coils. The switch operation is separated in two parts:
Keyfeel response:
A pair of electromagnets that push two center permanent magnets simulate the same interaction a spring produces in a normal switch, while also being capable of produce a difference in feedback via restricting or releasing the supplied current of the coils.
Analogic sensing:
In order for the controller to know how much current supply to a switch at a given moment, it needs an analog input. What an infrared sensor does is simply bounce infrared light into a surface and measure the result with a photodiode. The closer the surface, the stronger the measure. The square in the bottom part of the slider, which I call "reference surface" is nothing more than bare plastic with the purpose of producing such readings. For our purposes we need a high resolution proximity sensor so the switch feels smooth and not steppy.
Combining this two steps the result is a sort of Excel table we can play with, producing WHATEVER feel we want:
Not liking this one? Let's tell the controller to do something else, maybe you want to play a game and you are looking for a linear switch:
BOOM!
Now, this switch has two main issues: a whole keyboard would eat a fuckton of power, being necessary an external power supply and the controller must be way more complicated than usual, both being able to run a very large bunch of code in short time and having a massive analog GPIO. Still possible. Costs are a different situation.
I can also describe some other aspects like the fact that the switch has 8 pins, making it solid for PCB mounting, if you want a plate is meant to be screwed on the switches, not the switches to be clipped in. Anyways, I think I touched the central points quite well, thanks for making it to here!
