rubber dome without membranes?

[msiegel]

hi
i thought i saw one or two rubber dome keyboards that use a pcb instead of membrane sheets... does anyone remember what they are?

[zwmalone]

Topre.

[rdjack21]

Pure junk When I get a chance to look around I will see if I can find some pictures of how they were made. You don't really see them any more in current keyboards mostly because membrane sheets are cheaper to produce and more reliable.

There are also the old capacitive boards as well Keytronic made one. I had one of those back in day and they were junk as well. I mean what were they thinking foil on foam pure junk from a typing point of view. And they wore out fairly quickly mostly because of the foam.

[rdjack21]

Topre.

LOL very true. But I think he means those junk ones where they put a conductive material on the back side of the dome. Of course the stuff would flake off and wear out and then they would quit working.

[zwmalone]

The BTC's are the junk ones with the foil, but those aren't really rubber dome, they're foam n' foil.  The capacitive keytronics supposedly feel decent and have a PCB...

[clickclack]

hi
i thought i saw one or two rubber dome keyboards that use a pcb instead of membrane sheets... does anyone remember what they are?

There are tons of them, but again usually nothing recent. The first that comes to  mind is the Dell quiet key keyboard (But only a select few have them). That board has gone through so many internal changes its hard to keep up! If I come across some of my notes and more boards I can tell you others as well if you are interested.

I have seen so many twists on capacitive pcb type boards that its hard to remember them all, but indeed most of them are just rubber domes with a tiny condutive black dot in the center.

Interestingly enough I came across a new design (new to me) today for membrane boards. the board had keys with a seperate key stem that looked almost identical to an ALPS slider and had only a spring underneath it that would smash the membrane below. Attached to the slider thingy and the boards stem wall was a little metal leaf that looked as thought it provided some tactile response yet it still felt linear (very much like a black cherry switch).

anywho sorry for blabbing on...
=P

[clickclack]

I just happened to come across a pic just now of a board that has them, but I unfortunately can't find what board it is
But here is the pic anyway-

[msiegel]

those swirly contacts are interesting

[msiegel]

the board had keys with a seperate key stem that looked almost identical to an ALPS slider and had only a spring underneath it that would smash the membrane below

haha, that's a new one

[clickclack]

Nice pic titles you perv.   But I think he meant a hard PCB board, not a membrane.  99% of TV remotes are built with a rubber dome, little black metal disk under the rubber, and a PCB underneath.
There is a BIG advantage to those PCB boards if someone can find which keyboards have them.  You can mod the hell out of them by just soldering to the pads.
ClickClack - I'm SURE you must have one in those 600+ boards with a hard PCB and rubber dome.

I have a quite a few of the pcb mounted ones too, but the majority of the capacitive contact ones are of the variety that I posted. Of the PCB mounted ones most unfortunately don't seem to have the shiny metal contacts of the one you showed. They have this rough conductive black type paint, which can't be soldered to. Hmmm... maybe that conductive glue would work those types?

haha, that's a new one

No kidding its a strange bird indeed!

[timw4mail]

No kidding its a strange bird indeed!

It's probably quite common around the time that ALPS were going out and rubber domes were really taking over. Since the keyboard OEMS would have a lot of ALPS keys, they would design rubber dome mechanisms that could take ALPS keys.

Of course this is merely conjecture...

[lowpoly]

I have an old Silitek with conductive rubber domes on pcb. I don't think these are capacitive?

[clickclack]

It's probably quite common around the time that ALPS were going out and rubber domes were really taking over. Since the keyboard OEMS would have a lot of ALPS keys, they would design rubber dome mechanisms that could take ALPS keys.
Of course this is merely conjecture...

You would think, and it makes sense to me. The problem that I would have with that though is it's not quite the same as the ALPS slider (very similar). And it did not have rubber domes, it was just the spring on the membrane. But I know what you were thinking though. In one of the Wiki entries last nignt I did find something similar but not quite the same.

I have an old Silitek with conductive rubber domes on pcb. I don't think these are capacitive?

Hmmm... why wouldn't they be? The model F's are and don't they perform the same general function? :S   (scrambles to go look stuff up...)

[JBert]

The thing is that the model F PCB has larger surfaces to detect the capacity from compared to a rubber dome.

Most of those non-membrane rubber domes instead contain a bit of graphite so you get an actual current flowing between the contacts on the PCB.