TIL - Topre sliders are stabilized.

[bpiphany]

I actually hadn't thought about the possibility, 38 screws later...

Topre 2X+ stabilizer by Fredrik Atmer, on Flickr

The Caps Lock stabilizer is a bit unique. Some of the screws goes into the brass risers. Most of them however only sneaks through black plastic holes formed between the slider inserts and are mounted directly into the plate. There is one hole there between A and S. The plate is 1.3 mm thick.

Topre Caps Lock stabilizer by Fredrik Atmer, on Flickr

The mounting plate holes are actually not quite square making it impossible to put the slider inserts the wrong way.

Realforce 105U, Mounting plate by Fredrik Atmer, on Flickr

The right Shift rubber came off when I opened the board up. It's a mess fitting everything together again if the cups come off. I did this with my HHKB to scan the PCB, and it had enough of cups to keep straight.

Realforce 105U, PCB top with Rubber Cups by Fredrik Atmer, on Flickr

Nothing very surprising. I think the PCB on the HHKB is >2 layers. This one looks like ordinary 2 layers though.

Realforce 105U, PCB back by Fredrik Atmer, on Flickr

Details of the controller circuitry. I have higher res pics if anyone is interested. Today I also learned about multiplexers..

Realforce 105U, controller detail 1 by Fredrik Atmer, on Flickr


Realforce 105U, controller detail 2 by Fredrik Atmer, on Flickr

[RiGS]

I wonder why topre switches lack the annoying friction. The slider moves in that switch case in a similar fashion as the slider of cherry switches.

[redpill]

Them Topre folk know how to put a keyboard together.

[bpiphany]

Someone should put a link to this TIL in the Topre Wiki.

Otherwise it will fade away like most keyboard forum posts.

Actually, anyone feel free to add the photos or links there, I don't like messing around largely with other peoples wikis...

[bpiphany]

I wonder why topre switches lack the annoying friction. The slider moves in that switch case in a similar fashion as the slider of cherry switches.

Probably the larger area of interaction smooths over imperfections better. Also when hitting a key a bit off center, and the sliders being wider, the levering force "jamming" the slide might be smaller. Differences in materials and tolerances could surely play a role too.

[simon_C]

TIL topres are rubber dome

[Daniel Beaver]

Yep, that's why they're so damn nice. Incidentally, also why the Dell Quietkeys are so nice.

[bpiphany]

Ever wondered how large the capacitance of the Topre switch really is? Yeah, me too... This multimeter might do the trick I hope. Looks like a baseline of 5pF.

Capacitance of unconnected wires by Fredrik Atmer, on Flickr

I had to cut the traces to isolate the switch from the circuitry. I was aiming for Scroll Lock, but missed only by a hair =P Soldered in probe wires.

Close-up of Topre switch capacitor by Fredrik Atmer, on Flickr

8pF while released, minus those 5 lets say <~5pF.

Topre switch capacitance, released by Fredrik Atmer, on Flickr

14pF while pressed, so lets say ~10pF.

Topre switch capacitance, pressed by Fredrik Atmer, on Flickr

I don't really know anything about electronics, but if my measuring method is nearly okay that would mean at least a doubling in capacitance. Wouldn't be too hard to detect, would it? I need to take an electronics course...

[RiGS]

I wonder if it's possible to replace the wimpy topre springs to a stiffer custom made one. That way the all 30g topre domes with a 65g spring could be a nice linear switch combo, but without the annoying friction.

[bpiphany]

I wonder if it's possible to replace the wimpy topre springs to a stiffer custom made one. That way the all 30g topre domes with a 65g spring could be a nice linear switch combo, but without the annoying friction.

My layman answer would be that metals are all pretty much the same when it comes to affecting the gap properties of the capacitor. So yes I wouldn't see any greater problems doing it. Even if the properties are slightly different that could probably be adjusted for by changing some resistor somewhere. Didn't Topre announce a keyboard with a trim wheel? =)

[thebilgerat]

TIL people are perfectly willing to cut trace and solder leads to a 300+ dollar keyboard to double check capacitance figures.  Without much electrical experience.  Which is awesome!

[bpiphany]

I'm not completely noob with soldering and physics in general =) Just not a lot of electronics knowledge in specific. And "double check", are there numbers somewhere? And they are at least a little less than $300. I haven't done anything irreversible, yet...

[suprsmo]

Cheers for this. Found it a google search for Topre Stabilizers.