Rubber dome over membrane

[Daniel Beardsmore]

I finally got around to completing my rubber dome over membrane diagram:

Rubber dome over membrane, exploded.png (329.75 KiB) Viewed 1660 times

I've created a page on the wiki for it, in the new switch designs category:

[wiki]Rubber dome over membrane[/wiki]

I've also updated the [wiki]key[/wiki] page with a simpler version of the diagram, presently without annotations as they make the image too wide (I aim for 650 px maximum width).

Now there is no excuse whatsoever for people being unable to tell the difference between "membrane" and "rubber dome", and finally we have an official resource that explains what is actually inside a typical computer keyboard and how it works. (Someone else gets the fun of extending this via CAD to cover scissor! Also, on the [wiki]key[/wiki] page, I left the keycaps blank as there's no way I can put any other legends on them! "F1" was fairly easy as it's all straight lines — the above image is pure Inkscape SVG with an axonometric grid, not CAD. Hence why the wiki version has really grainy text.)

[002]

Nice work, man!

[Vierax]

Wow ! very understandable and complete. Only one thing, the integrated slider is a bit hidden by the top cap : It can be improved with reducing the size of the side of the cap or increasing the length of the slider. It's a cheat but the goal is to show all pieces, no need to be accurate

[photekq]

Wow. Really great work, Dan.

[Jmneuv]

Good style.

[Muirium]

Now that's a diagram! Sadly, I can't even picture how to add scissor switch to it without messing it up! Naturally, this exposes the real problem: I don't actually know enough about that mechanism, just the overview.

[Daniel Beardsmore]

Wow ! very understandable and complete. Only one thing, the integrated slider is a bit hidden by the top cap : It can be improved with reducing the size of the side of the cap or increasing the length of the slider. It's a cheat but the goal is to show all pieces, no need to be accurate :)

I've already cheated with the measurements as much as I'm comfortable. That integrated slider is annoying, and I made it as visible as I could. To be fair, it's one of the least significant parts of the image, and one that anyone who's afraid/unable to take a keyboard apart, can see for themselves.

Now that's a diagram! Sadly, I can't even picture how to add scissor switch to it without messing it up! Naturally, this exposes the real problem: I don't actually know enough about that mechanism, just the overview.

I did have a go at drawing a plan of one, but it's not terribly clear:

[wiki]Scissor switch[/wiki]

The easiest way to think of it is a boxing glove that comes out on a scissor arm. The boxing glove's orientation remains constant despite the motion of the linkage.

The simplest version of that concept is a diamond pantograph on a tram. Scissor switches are the same thing, but 1/2 a diamond along, with one side supported by guides instead of being hinged:

Scissor switch diagram.jpg (142.04 KiB) Viewed 1576 times

I've learnt that scissor keycaps are pretty easy to remove and reattach, so it's easier to examine one for real.

An animated GIF would be of good use here.