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

idollar · 01 Mar 2016, 14:01

For those that are not following the GB thread ... two ideas have popped up with it:

1) To insert PADs between the control and alt keys. This would allow to cut the case and insert two additional 1u keys in the middle. The barrel plate will need to be modified to host a new barrel also. I committed to check the options in the PCB to allow it.

2) To create a version of the xwhatsit controller matching the size of the original M controller. This will allow the USB cable to connect directly into it from the external side of the case.

As said, I will look at the bullet 1) above. I do not have the time to check the 2). Is there anyone willing to do it ?
I could order a test board together with the GB to check it if a potential design is done in time.

wcass · 01 Mar 2016, 16:39

Sure, i'll take a stab at that.

Do tell me what USB connector you guys want - standard B, mini B, micro B, or C. It may be possible to do all using a daughter board that adapts standard B to all of the others.

Hypersphere · 01 Mar 2016, 17:26

wcass wrote: ↑Sure, i'll take a stab at that.

Do tell me what USB connector you guys want - standard B, mini B, micro B, or C. It may be possible to do all using a daughter board that adapts standard B to all of the others.

Thanks, wcass!

There are of course pros and cons for each type of connector. Standard B is a bit large. Mini B is still used by many and everyone has a mini B cable. Micro B was supposed to be the new standard and supposedly more durable than mini B, but it seems that not many keyboard makers have adopted it. C is the latest thing, which would "future proof" (ha!) the board, but it is still relatively uncommon. Could the daughter board be installed with a removable connector so that it could be swapped out later? At the moment, all things considered, I think I would prefer mini B.

idollar · 01 Mar 2016, 19:21

wcass wrote: ↑Sure, i'll take a stab at that.

Do tell me what USB connector you guys want - standard B, mini B, micro B, or C. It may be possible to do all using a daughter board that adapts standard B to all of the others.

I have always thought that we could design a PCB allowing to solder the three types of connectors, perhaps with multiple overlapping pads/mounting-holes. I anyhow would leave the decision to you, as you will do the work.

I also found this some time ago: https://www.youtube.com/watch?v=DYIDDoRS25Y
Related to this: keyboards-f2/solenoid-in-model-m-t11683.html
And also here with pictures; https://geekhack.org/index.php?topic=69 ... msg1727558

So perhaps, the board could allow to connect the original model M membrane directly, so it could be used as a replacement for the original controller also.

All the above are my ideas ... just that.

Techno Trousers · 01 Mar 2016, 19:52

FWIW, I'd vote for a USB Type C connector. It's just starting to gain traction now, but in 10-15 years i predict we'll be hard pressed to source a replacement mini B cable, for instance. I'm hoping my FSSK will be an heirloom device for future generations.

wcass · 02 Mar 2016, 00:18

Standard USB-B plug is the closest in size to the original SDL plug, so would be the best at filling the hole in the case. The footprint pattern is very simple and much further back than the other 3 USB plug options. My original idea would be to have little daughter PCB with through holes to match the standard USB-B and convert to one of the other plugs. This would raise the plug up the thickness of a PCB, but that would actually slightly help to fill the relatively huge case hole.

I may be able to place one (or maybe two) USB connection footprint in front of the standard B on the controller PCB, but you would need to keep any unused footprints covered with Polyimide tape. If i try to wedge two footprints in there, they would be off-center of the case hole.

Let me know what you guys want.

Hypersphere · 02 Mar 2016, 00:57

@wcass: I like your first plan best -- standard USB-B. Sounds like this would be the best match to the original case opening.

vivalarevolución · 02 Mar 2016, 01:09

Hypersphere wrote: ↑@wcass: I like your first plan best -- standard USB-B. Sounds like this would be the best match to the original case opening.

I second this. Phosphorglow did this with his controller and it worked well.

XMIT · 02 Mar 2016, 07:14

Don't worry about the opening at the back of the SSK too much. I'm working on 3D printing a part to resize that opening to any connector. I don't think that should be an argument for USB Type B.

I prefer smaller connectors like micro USB as they offer more routing options.

shreebles · 02 Mar 2016, 10:12

Agree with XMIT, the size of the connector shouldn't make this decision.
USB-B was already old 4 years ago, and used only on printers and some old external drives, just let it die.
Techno Trousers' argument is also valid when looking at the future but I do believe that you can still change and adapt the connection later when type C cables are more common. When I think about which type of cables we all have lying around, and what you can get from Pexon and the like, I think USB mini or micro.

Halvar · 02 Mar 2016, 15:11

Wcass, it's great that you're planning to do that! What kind of internal connector to the keyboard pbc did you think of using? Maybe there's a better way than soldering a cable directly to the connector. There's a bit more space in a Model M after all compared to the models xwhatsit was designing for.

Regarding the USB connector, any kind is fine with me.

idollar · 02 Mar 2016, 16:13

Halvar wrote: ↑Wcass, it's great that you're planning to do that! What kind of internal connector to the keyboard pbc did you think of using? Maybe there's a better way than soldering a cable directly to the connector. There's a bit more space in a Model M after all compared to the models xwhatsit was designing for.

Regarding the USB connector, any kind is fine with me.

It would be my preference/idea to use components that a non-expert could solder in the board. So non SMT but old-fashion ones, and jumpers for the configuration/reset.
Regarding the connector, I would suggest to use a setup with a connector (I have demonstrated that a connector in the middle of the ribbon cable works) that somehow would allow the original matrix to be connected, directly or indirect like this:

Correction/Edit: Better than the above

Halvar · 02 Mar 2016, 16:56

Yes, wcass could provide holes on his pcb that you can use to solder in these membrane connectors, like on an original M controller. The membrane connectors themselves can only be used with membranes, but they have the standard pitch of 0.1'' on a Model M. Which means these same holes could, in an FSSK, be used instead to to solder in a different kind of pcb connector and avoid the need for a connector in the middle of the cable But it's important to plan which kind to use and where to place the holes for the whole assembly to fit inside the FSSK.

For example the kind of connector that was used on PC board for IDE cables would work, if they're not too high to fit. They would need a second row of holes though. Or just one row of angled standard connectors (with more pins):

In any case, this needs some planning to get the space restrictions right.

wcass · 03 Mar 2016, 00:31

idollar wrote: ↑.... So perhaps, the board could allow to connect the original model M membrane directly, so it could be used as a replacement for the original controller also....

But your design has rows left and columns right. M's have rows/columns the other way around. Also, F switch is inherently NKRO so the controller does not have anti-ghosting algorithm.

In a small batch of 3, the controllers will run about $35 each for first 3 prototypes. In larger production, the price would go down to $25-$30 each.

A question to you all about how to attach the cable between the matrix and controller; soldered or connectors? Connectors would be most convenient, but also most expensive. Connector choice for matrix side is very limited due to space and i would think it very likely any connector would pop off the matrix PCB when it is bent. We could use a connector on controller PCB, and use solder or Z-tape on switch matrix PCB. Ribbon cable directly soldered to both PCB will be least expensive but you would need to assemble your keyboard with the two parts tethered together.

"solder both sides":
Controller might ship with cable pre-attached. Someone would need to solder to switch matrix and then assemble the keyboard that way. i would use 0.1" pitch ribbon cable; three of these ... http://www.digikey.com/product-detail/e ... -ND/857692
Add about $2 for this solution

FFC connector on controller, Z conductive tape at switch PCB:
No soldering!!!! cable stuck to switch matrix, but removable at the controller. i would use 1.25mm pitch FFC (2.54mm pitch are just not available); three of these ... http://www.mouser.com/ProductDetail/Mol ... V1OcokE%3d
plus 3 of these ...
http://www.mouser.com/ProductDetail/TE- ... oPqCvPc%3d
plus some z conductive tape.
Add about $8 for this solution.

I like the FFC connector option the best for production, but it is not a good fit for this prototype as the cable pitch can't be adjusted to fit the prototype switch PCB. The ribbon cable option would be better for that. If you guys like the FFC connector option, we could try it out on a future switch matrix prototype.

I would be happy to design and assemble these prototype controllers, but will need volunteers to test them (i don't have an SSK). The volunteers must already have an idollar switch matrix PCB. Sponsors to fund the prototype development and production would also be appreciated.

Halvar · 03 Mar 2016, 04:20

I haven't used z conductive tape yet, it sounds like a cool solution, but I have trouble trusting the stability of both the mechanical and the electrical connection with the narrow strip we would be using. And, as you said, there's the pitch issue. Someone would need to test this first. Maybe I don't understand the geometry you have in mind.

The solution I would trust would be ribbon cable soldered on the matrix side and with some sort of connector on the controller side.

idollar · 03 Mar 2016, 07:16

I would be happy to design and assemble these prototype controllers, but will need volunteers to test them (i don't have an SSK). The volunteers must already have an idollar switch matrix PCB. Sponsors to fund the prototype development and production would also be appreciated

I am your volunteer

I can help with both things.
I could order some controller prototype PCBs together with the FSSK PCBs, solder the components, program the set and test it.

idollar · 03 Mar 2016, 07:28

I like the way this us going. It is becoming a true community project.

We started with just an idea, lets see where we end up

Thanks again wcass. Many thanks !

Hypersphere · 04 Mar 2016, 00:52

@wcass: Do you have all the parts for an FSSK except the SSK? If you need an SSK for the further development of this project, I might be willing to part with one for a reasonable price. Please PM me if you are interested.

There are also some SSKs currently on eBay; the ones that are in excellent shape are of course going for rather high prices, but there are some in the process of gathering bids that are still at very low prices. It will be interesting to see what the final prices are.

XMIT · 04 Mar 2016, 03:25

wcass, maybe you can do some prototyping with the FEXT (full sized cousin of FSSK). The controller board sizes in the Model M and SSK should be the same.

wcass · 04 Mar 2016, 03:32

I don't have a SSK, so didn't sign up to get a switch matrix PCB.

I really enjoy the design process. I would happily design keyboards that i would never use. I don't like sourcing vendors (i tend to pick one and stick with them) or organizing group buys (I tend to give it away rather than sell) so it is always best for me to partner with folks that have the expertise and drive to do the stuff that i am not skilled at and/or have little desire to do. When this is done, i will not be running a group buy - i'll publish and let anyone interested take it from there.

wcass · 04 Mar 2016, 03:35

XMIT wrote: ↑wcass, maybe you can do some prototyping with the FEXT (full sized cousin of FSSK). The controller board sizes in the Model M and SSK should be the same.

Good idea. I do have a few of them around the house. I even have a recent Unicomp.

idollar · 04 Mar 2016, 07:05

I have woken up with a new idea in my head:

The original M controller required lot of power. This was one of the reasons not to have a bluetooth converter inside: the battery will not last very long. If an xwhatsit is used this may not be a limitation allowing for a long lasting charge. Thus, it may be food to have an internal usb termination = pads to allow for a future evolution to add a bluetooth adapter.

I am not into bluetooth and I like my keyboards cabled, but I am sure that many people would like an FSSK/FEXT or SSK/EXT enabled with bluetooth.

What do you think ?

Madhias · 04 Mar 2016, 07:28

Then I would instantly make this mod

Halvar · 04 Mar 2016, 08:59

idollar, I don't think an internal usb termination would be the best way. What you need to add a bluetooth module would preferably be
a) a serial port (RX and TX pins of the microcontroller). Xwhatsit already leads those out as part of his ("solenoid") extension port I think.
b) pins to power the controller over an external power source,
c) pin to lead out the USB's power for charging.
d) if possible, as many GPIO pins as are left on the microcontroller to allow for battery control, a low battery LED, a switch between USB and BT and maybe other things.

We discussed this in detail in phosphorglow's controller thread.

vsev · 04 Mar 2016, 10:29

Waiting now for additional barrel plate from Muirium's Unicomp GB and will dive into the mod quickly!

Hypersphere · 04 Mar 2016, 21:35

My own preference is to keep things as simple as possible to ensure that the FSSK works. I prefer a cabled (wired) connection rather than wireless.

As a matter of fact, I am typing this on my SSK using a direct SDL to USB active converter cable. Very nice.

Halvar · 04 Mar 2016, 21:45

@Hypersphere: sure, we're talking about a full wired xwhatsit controller here, only with a Model M form factor and some additional pins that would give you the option to add wireless later if you want.

idollar · 05 Mar 2016, 11:57

I enjoy the FSSK 0001. Yes, I really do.
I have not found any other keyboard that I like that much !!

I thought about getting an F77 from Ellipse. I will not. Since this keyboard is on my desk, I have parked my "regular" Fs.

We have created what I always wanted. It is so nice that I keep moving it from the office to home and back. I will need to mod the second SSK that I also have. Fortunately enough I have enough flippers. For the time being I will need to use the extra xwhatsit controller, but once wcass comes with the new xwhatsit PCB design there will be no need to use it

I like this keyboard, yes I really do.

Hypersphere · 05 Mar 2016, 14:43

@Halvar: Thanks for clarifying things.

@idollar: Good to know! I think that many of us have wished for this -- an SSK, but with Model F switches* -- and you have made this possible!

*As per my thread back in 2014:

workshop-f7/feasibility-check-convert-s ... ml#p292490

micrex22 · 05 Mar 2016, 19:21

shreebles wrote: ↑Agree with XMIT, the size of the connector shouldn't make this decision.
USB-B was already old 4 years ago, and used only on printers and some old external drives, just let it die.
Techno Trousers' argument is also valid when looking at the future but I do believe that you can still change and adapt the connection later when type C cables are more common. When I think about which type of cables we all have lying around, and what you can get from Pexon and the like, I think USB mini or micro.

I actually have a lot of things with USB-B that are recently manufactured such as a bunch of audio-related equipment and USB hard drive 'toasters'. And a USB-B to USB-C cable could always be purchased:
http://www.belkin.com/us/p/P-F2CU035/#

Using miniaturized connectors on keyboards means they're a lot more fragile and less durable. As such, mini USB is probably the best option (especially since the cables are far more common than micro USB ones).