questions about keyboard internals

[Frohst]

Well after trying mx blues and blacks at a friend's house a while back, I can't get over my membrane's feel. Unfortunately I also can't type on a straight board for more than an hour without my wrists and hands getting pissy. So after seeing lanx's conversion I figured I'd try with my Logitech Wave. I would like to buy as little as possible, recycling as much as I can. Before I start putting money down on doing this figured I should probably know a bit more about hwo these things work XD

first off, are there designated output/inputs on keyboard switches, like currently my board has the 12 right traces going to the top of the membrane and the 12 left traces going to the bottom. If i were to mimic the layout on a pcb does it matter which side of the controller is tied to a pin of the cherrys.

also my board has fake switch spots, like on the plastic membrane sheets there are the contact circles but no rubber dome above them, is this just Logitech being silly? or do these things serve a purpose?

third, all of the media keys are in weird spots and/or don't depress anywhere near 4mm. Considering how these really don't affect the typing feel is there a way to integrate the existing plastic membrane sheets with a pcb. like if I were to press the sheet's traces onto copper pcb traces would there be enough signal for it to function?

fourth, similar to the above, my controller interfaces with the membrane by having the sheets' traces pressed onto black pads on the controller. If i just pressed copper pcb traces to those black areas everything should be fine right?

finally, from what I've read I should like clears (tactile and stiffer than blues), but what worries me is people saying its a long rounded bump compared to blues. What I loved about blues compared to membrane boards was the sharp distinct bump. Any input on this? should i use brown+black spring or blue+black spring instead?


Thank you! and sorry for the run-ons and speeling errors which I know are up there. Will probably edit in additional questions as they come.

[theferenc]

Welcome to geekhack!

I'll toss out answers to the ones I can.

also my board has fake switch spots, like on the plastic membrane sheets there are the contact circles but no rubber dome above them, is this just Logitech being silly? or do these things serve a purpose?

It's intentional. Just like on the IBM keyboards, a single membrane layout supports all of the national physical layouts. So rather than having a custom membrane for each layout, they just change which have keys above them.

third, all of the media keys are in weird spots and/or don't depress anywhere near 4mm. Considering how these really don't affect the typing feel is there a way to integrate the existing plastic membrane sheets with a pcb. like if I were to press the sheet's traces onto copper pcb traces would there be enough signal for it to function?

Highly unlikely. Your best bet would be something like Cherry microswitches in place of those.

fourth, similar to the above, my controller interfaces with the membrane by having the sheets' traces pressed onto black pads on the controller. If i just pressed copper pcb traces to those black areas everything should be fine right?

You will need an entirely new PCB, which feeds its own controller. See Lanx's mod for the details. It looks like an absurd amount of work, but a Topre based MS Ergo would be a nice toy. Too bad the μTRON is so damn expensive.

Hopefully that helps somewhat.

[False_Dmitry_II]

Would it be possible/easier to buy a similar sized (or smaller, maybe even tenkeyless) keyboard, then hack up its PCB in half, fit it into the other keyboard and use its actual keys in the same holes? That way you just have to solder wires to/from the parts that were broken off, and possibly even use its controller/cord. Although getting it to line up at all would likely be quite hard.

[theferenc]

That's exactly what Lanx did, isn't it?

[Frohst]

would be easier than lanx's actually since the wave's waviness is due to differing key heights, the inside is all level (except a little pop up for media funcs). I was hoping to keep the current controller so as to keep the wireless and have my mouse and keyboard on 1 usb, but if just lining it up and pressing won't conduct enough then i guess i can use a controller. I haven't bought anything yet and as far as i know cheapest way to get cherries is just buy a POS board.

other reason for keeping controller was so i could just mimic current membrane layout and not have to know how a matrix should be set up to get xKRO XD

unfortunately the keys are not in straight lines so really can't use an old pcb's traces. Was going to do something like what this guy did [/URL] http://geekhack.org/showwiki.php?title=Island:15542 to make a pcb, besides sourcing the actual corrosives doesn't seem too bad, just time consuming.

heres a pic of the board so you guys have an idea of what i'm talking about

so yeah close to straight but just curvy enough to make it surprisingly comfortable XD

[Ascaii]

Something else you should consider is doing what hoggy did.
He took two programmamble Access-Is POS boards (fully programmable) and turned them into a split, ergo board.

http://deskthority.net/viewtopic.php?f=2&t=283

[Frohst]

huh, awesome idea. too bad I am a heavy gamer so splits are out.

so on mechanicals the controller is still a separate card that can be de-soldered and transplanted right? if i were to match the old board's matrix it should work right?

If that's true will just do what false said, just with a new pcb.

more practical question, how strong a soldering iron should I be using for this? Currently have a couple year old 25w plug-into-the-wall-and-it-gets-hot kind and a 100w gun >.<