Let's create the FSSK/FEXT = DONE !!!!

[idollar]

---------------- Special thanks ------------

To xwhatsit for his controller and associated software. Thanks a lot !
To wcass for his help in designing the PCB. Thanks you !

---------------- Thread summary ------------

-- Last update 28.Feb.2016
-- Note: please use the links in the post to find additional information --

During 2015, we came to the idea of replacing the matrix of an IBM Space Saver Keyboard (SSK) with the technology of the F models, which is capacitive.

The work done by xwhatsit with the controller and the demonstration that a different PCB layout could be used by wcass with the xtant in the Bringing the IBM PC XT into the 21st Century thread led me to this idea.

The result of the project has been the working FSSK that I am using to type this post. The board ensures the best of the bucking spring word: the SSK layout and the F feeling that IBM decided to evolved into a membrane to save cost.

The mod will not damage any part of your SSK. Depending on the SSK model that you have, you may need to sand/cut some small parts of the barrel plate. Nothing drastic. In summary, it should be possible to revert the SSK to its original configuration (screw modded) if you keep the original parts.

A side consequence of this project has also been the so-called FEXT: a PCB that could be used to replace the membrane of the regular (and easy to find) IBM extended model M, and why not, the F122. The latest (F122) has not been started at the time that this post is written.

At the this time there are two working prototypes. We have set a "registration page" to track the future of the project.

In order to make this sophisticated mod, there is a need to have some elements:

1. A keyboard - SSK to create the FSSK or Regular Extended M to create the FEXT
   The keyboard will need to go through a screw mod (I do not recommend to use a bolt mode). A good link to post showing how to do it can be found here thanks to Madhias. Check the size and type of screws that he is using as well as the size of the bit that he used to drill the holes.
2. A controller - Refer to the xwhatsit controller above
3. F flippers - Currently, there are two sources for them: old F models (XT, bigfeet are good candidates because of the layout) or a separated project run in the forum. I would not recommend the latest as the price is too high. My recommendation is to wait until you find an F keyboard beyond the restore threshold.
4. The PCB (FSSK or FEXT)

In the this posts, you can find some pictures on the mod process. It is not very detailed, but please do not hesitate to ask for questions. We can update the posts with them.

---------------- How to source the PCB ------------

I have been using http://www.pcbway.com
The quality is excellent. Very recommendable.

(refer to workshop-f7/f-ssk-t10744-390.html#p278664)

Refer to the group buy post

---------------- Future work ------------

To create a version of the xwhatsit controller with the shape of the model M controller, suitable to replace the original controller. The design should allow to use it with the regular SSK/EXT membrane keyboard as well as the FSSK and FEXT.

---------------- Use EXT internals in a SSK (FSSK) ------------

hypkx has created this thread in which it is explained the excellent work that he has done to reuse the internals of a EXT into an FSSK !

Well done !!!

---------------- Latest PCB version ------------

FSSK v1.00
FEXT v1.00B


---------------- Additional information ------------

Write in this thread of send me a PM.

---------------- The original post starts here ----------

Hi,

I have been thinking on this project since some time already.
The idea is simple and I believe that many of you already had it, so it is time to start implementing it:

• 1.- Grab a M-SSK
  2.- Remove the rivets.
  3.- Remove the flippers
  4.- Replace them with F flippers
  5.- Design and produce a PCB matching the SSK layout
  6.- Connect it to a F xwhatsit controller.
  7.- Configure and enjoy.

Getting the parts is difficult and somehow expensive:

• 1.- Thanks to Cindy I have one for this purpose.
  2.- 3.- Here we need donors. Some time ago, is saw a guy in ebay that had parts from an XT and a Bigfoot. I asked him to sell me everything but the cases. I now have enough from these.
  5.- This is pending. We will have to do it. Experience with the Xtant shows that it is doable.
  6.- I have one of these for this purpose.

Now that I have finalised the FMK, it is time to start with this project.
I will be busy the next week, but I decided to post this to start a discussion and collect your ideas.

Note: this time there will be no poll to decide the name. It must be FSSK

i$

[seebart]

Very interesting! I am looking forward to your updates.

[Nuum]

Nice project! Do F flippers fit into M barrels? Thr spring should be no problem, but maybe the hinges?
I also think that having a plastic barrel plate might interfere with the classic Model F feel, like it does in wcass' 75% M/F hybrid..

[idollar]

Here are the parts that I have mentioned:

DSC_2857.jpg (181.04 KiB) Viewed 32803 times

[idollar]

Nice project! Do F flippers fit into M barrels? Thr spring should be no problem, but maybe the hinges?

Yes, they fit. I have not tested how good is the flipping. I wanted to test the SSK to be working before starting this new project. This is the next step to report.

I also think that having a plastic barrel plate might interfere with the classic Model F feel, like it does in wcass' 75% M/F hybrid..

This may be the case, indeed. I also have the barrels from the original keyboards. We could create the supporting metal plate with the SSK layout as an alternative. The problem is that I guess that the keys will be higher than normal. The sum of the PCB plus the barrel would be higher. I guess that a thin PCB will be similar to the original thickness.

[chzel]

Well, F flippers are nothing like M's, I don't think they'll fit. You'd need a solution like the XTant.
It's a great project, I hope it works out!

[idollar]

chzel,

It is confirmed, the F flippers flip in an M barrel board !

Pictures will follow

[idollar]

Apologies for the quality of the pictures. I do not have lot of time right now. I am posting while doing, real time:

Remove the keycaps:

DSC_2858.jpg (126.46 KiB) Viewed 32772 times

Remove the screws:

DSC_2859.jpg (132.5 KiB) Viewed 32772 times

DSC_2860.jpg (146.17 KiB) Viewed 32772 times

Replace the flippers:

You will notice that 4 of them do not fit. This can be resolved by modifying the plate or using an older one. I have to make my mind. I may use my other SSK for this project.

DSC_2861.jpg (154.53 KiB) Viewed 32772 times

DSC_2862.jpg (159.84 KiB) Viewed 32772 times

DSC_2863.jpg (164.42 KiB) Viewed 32772 times

And mount it back.

DSC_2864.jpg (134.84 KiB) Viewed 32772 times

DSC_2865.jpg (137.32 KiB) Viewed 32772 times

Conclusion: leaving aside the four flippers that can be resolved, the flippers are compatible.

[idollar]

Let me anticipate the question that all of you may have in mind:

Does it feel like the M or the F ?

It definitively fells like an F.

The answer is wirten after comparing a normal MSSK, an F-107 (the FMK) and the frankenstein.
Actually, and as the two SSK look identical I made a blind test, with the help of my wife. I could say without any doubt which one was the F.

i$

[Muirium]

Not bad. It's been so long since I was last inside a Model M that I didn't realise there was enough room to do this. Crafty!

What other layers have you got in your current test model besides the barrel plate, flippers and metal backplate? I wonder if F's foam contributes to the feel, or indeed M's mat. Have you tried simply reassembling this with Model M membranes and seeing if it just works? That'd be a crazy hybrid! And I'm not sure which it would feel more like.

I assume you're thinking of filing down the flippers so they fit in the limited space on the C, V, comma and dot keys. Annoying that Copy and Paste are affected, I use those shortcuts so often I'd notice any inconsistency every day.

You'll need a large, custom, flexible PCB, of course. Hope you're in touch with Wcass!

Incidentally: Unicomp still sells whole SSK barrel frames. Chzel and me bought two in April. A useful spare part if you do need to mod the frame instead.

[Mal-2]

Conclusion: leaving aside the four flippers that can be resolved, the flippers are compatible.

How badly would it affect the feel if you were to shave the flippers to fit the case? It doesn't look like the hinges are affected by the interference, and I think someone showed (on this forum) that even the M flippers are adequate for sensing on the F plate, though not ideal. You wouldn't be losing nearly as much surface area as that.

[Muirium]

I bet clipped F flippers would work fine. The question is whether they would feel fine.

M "hammers" though, well, I doubt it. Those are plastic. Cap sense needs a conductor. Was this claim backed up? Was it super weak signal? (They could have been sensing the spring behind the hammer.)

F flippers are actually plastic that's coated with a dark conducting compound. Just like Beamspring flyplates. This gives the cap sense pads something to see. As does Topre's conical spring.

[idollar]

Not bad. It's been so long since I was last inside a Model M that I didn't realise there was enough room to do this. Crafty!

What other layers have you got in your current test model besides the barrel plate, flippers and metal backplate? I wonder if F's foam contributes to the feel, or indeed M's mat. Have you tried simply reassembling this with Model M membranes and seeing if it just works? That'd be a crazy hybrid! And I'm not sure which it would feel more like.

Just the metal plate. The foam only ensures that the barrels sit well with respect to the top metal layer.

I assume you're thinking of filing down the flippers so they fit in the limited space on the C, V, comma and dot keys. Annoying that Copy and Paste are affected, I use those shortcuts so often I'd notice any inconsistency every day.

You assumption is correct. But let me see first my other barrel plate. I have another SSK.
I may also get an unicomp one for this purpose. I do not want to kill a "real" one.
Anyone willing to help shipping to Europe ? I just ordered so many things ... I feel stupid.

You'll need a large, custom, flexible PCB, of course. Hope you're in touch with Wcass!

We are in touch. I have the details that I need . Thanks Wcass !!!

Incidentally: Unicomp still sells whole SSK barrel frames. Chzel and me bought two in April. A useful spare part if you do need to mod the frame instead.

That's what I meant above. I will need one or two of these.
Do you have pictures with the details of the 4 flippers that do not fit ?

[idollar]

Conclusion: leaving aside the four flippers that can be resolved, the flippers are compatible.

How badly would it affect the feel if you were to shave the flippers to fit the case? It doesn't look like the hinges are affected by the interference, and I think someone showed (on this forum) that even the M flippers are adequate for sensing on the F plate, though not ideal. You wouldn't be losing nearly as much surface area as that.

Good idea. It will need to be tested once we design and get the PCB.

[idollar]

I bet clipped F flippers would work fine. The question is whether they would feel fine.

M "hammers" though, well, I doubt it. Those are plastic. Cap sense needs a conductor. Was this claim backed up? Was it super weak signal? (They could have been sensing the spring behind the hammer.)

F flippers are actually plastic that's coated with a dark conducting compound. Just like Beamspring flyplates. This gives the cap sense pads something to see. As does Topre's conical spring.

Without any metal in the foot, the capacitance will not change and therefore the controller will not see the key being pressed. This is my guess.

[hammelgammler]

WOW! If that works you are the man.
A FSSK would be even nicer than an Unsaver! Holy moly what I would give to have a FSSK!

Any plans to do more PCBs if this works? I would be definitely interested in one PCB if it works out!
Damn that's the dream right here for me.

[ramnes]

What's the point of making a PCB if it already feel like an F? The F flipper can't activate the membrane?

[chzel]

The M flipper has a small nub to push on the membrane, and besides,capsense is the point!

[Muirium]

Yup. Cap sense is nkro and Xwhatsit's controller and software is the best of the best. I wish I could use that software on my non cap sense boards too!

[idollar]

What's the point of making a PCB if it already feel like an F? The F flipper can't activate the membrane?

I could give it a try, but I guess that it won't work.
The foots are different. They hit in different places.

[idollar]

WOW! If that works you are the man.
A FSSK would be even nicer than an Unsaver! Holy moly what I would give to have a FSSK!

Any plans to do more PCBs if this works? I would be definitely interested in one PCB if it works out!
Damn that's the dream right here for me.

Step by step ... lets try a single PCB (or various prototypes if anyone is interested also) with a regular Xwhatsit. If it does work we may integrate the controller in the PCB. This will reduce the price.

Note also that if it does work, it could be applied to a regular M also.

The issue, again is the availability of the F flippers. I had to use two donors, an XT and a Bigfoot.

[Muirium]

XMIT must be sleeping. I expect him to jump in with pricing for F components soon!

Hint to XMIT: When it comes to Bigfeet all we really want are the barrels, springs & flippers and caps. (Maybe the IBM badge if it can come off nicely.) The boards themselves are hopelessly expensive to ship here. But Model F parts are good.

[ramnes]

I would be in for a F parts GB.

[Muirium]

XMIT's already hoarded the necessary boards. (He trucked to Cindy.) So it's more of a storefront than a GB!

[idollar]

The question on building the required flippers (feet) was already raised here.

Note also that this project will need some time. I am a busy person ...

[Redmaus]

sheet you guys got me really excited. I am typing on my SSK right now and having this guy feel like an F sounds great. I would be in for an F parts group buy(or storefront?). I am glad I already claimed a bigfoot from XMIT but at the same time I want to use it not scrap it for parts. I wish there was another way to get flippies. The problem I see is the flippies are capacitative so you couldn't just 3-D print them. Oh and if you aren't going to be needing those black M hammers anymore I would like them for the model W.

[seebart]

I am sceptical it will feel 100 % exactly like Model F. Sure, more like Model F. It is a great idea though. Reminds me I got plenty F flippers around, just no spare ones.

[Muirium]

I'm skeptical too. Didn't mean to indicate I wasn't, if I did. I also have my doubts about daring creations like Wcass's Model W in that respect. Only your fingers can tell you in the end. Hell, even different models of Model Fs vary in feel. Every ingredient alters the dish…

[seebart]

Very true. But it's still a good idea to try it anyhow. It might become THE Frankenstein success.

[idollar]

I am sceptical it will feel 100 % exactly like Model F. Sure, more like Model F. It is a great idea though. Reminds me I got plenty F flippers around, just no spare ones.

For the time being you will have to trust my fingers.

It is not an M for sure. It is not an metal F (107 or similar). But it is VERY close if not identical to the F122 that I worked into an ISO layout.

I will try to get the project through. I have been collecting the parts for months. Now that I have them, I must do it.

It will take some time. I will be busy during the next 1,5 weeks.