[IC] cx87-88h: a multi-layout hotswap TKL PCB

[doctorboy]

ClackX cx87-88h
A multi-layout hotswap TKL PCB



Hello everyone, I'm doctorboy from Portugal and I would like to introduce my new project, a multi-layout hotswap PCB.

I'm an ISO lover and always try to build my boards with the ISO layout. It is also very normal to me that when building a new keyboard, I don't get the configuration right on the first try. I enjoy doing 2-3 different configurations to see what I prefer the most. In my point of view, this is one of the strongest use cases for hotswap PCBs. They allow one to easily change the configuration and find the right combination between plates, switches, etc. so I can then use the solderable PCB for my final build.
However, hotswap PCBs usually only support one layout, and even on very popular TKL boards, ISO layout is not available on the hotswap version. TKL layout also offers a multitude of different variations (USB port needed, USB daughterboard needed, F13 layout, 7u spacebar, etc.), which makes having the right hotswap PCB for the board that you are buying, very challenging.

So, I decided to make something about this, and I designed a multi-layout hotswap PCB.

English is not my native language; sorry in advance if some explanation or message is unclear.
I leave below the link for the IC form, where all feedback is very much welcome.

IC Form

Without further ado, I'd like to present the project more clearly.


0. Contents

• LAYOUT SUPPORT
• GEEK AREA - SPECS
• PHOTOS
• NOTES AND PRICE
• CREDITS AND FINAL NOTES

1. Layout Support




3. Geek Area—Specs

• FR4 TKL PCB with 1.6mm - with 0.25u space between the two top rows.
• Programmable via QMK/VIA/VIAL.
• Similar footprint as Hiney TKL h87/88 PCBs.
• Support of F12 and F13 layouts.
• Support of ANSI and ISO layout.
• Support of WKL/WK 7u and standard ANSI (6.25u) bottom row.
• Support of stepped Caps Lock.
• Compatible with right-side USB port (located between F12 and PrintScreen key).
• Includes JST and Molex connectors to support Unified daughterboard C and S series (JST placement is similar to h88nu board).
• Breakaway USB port for cases that use USB daughterboards.
• North-facing spacebar stab (the stab wire is located on the north side of the switch).
• Powered by STM32 MCU.
• One physical reset button in front and another on the back, for facilitating access.
• ARM debug pins.
• No RGB (underglow or per key).
• No meme or flex cuts.
• Only one led in the scroll lock key, since by supporting the stepped Caps Lock, there is no space for the Caps Lock led.
• Black colour (likely matte black) solder mask w/ white text and a cool design on the top side.

Note that compatibility will vary for this PCB. It is not a drop-in PCB for any TKL. It will be the buyer's responsibility to ensure that the PCB will work with their target case/board. As a starting point, you can consider this PCB compatible with boards that are compatible with Hiney H87/88 north spacebar versions.


3. Photos
I apologise in advance if the quality of the photos is not the best.

Prototypes




4. Notes and Price

Multi-layout support using hotswap sockets is only possible if we play with the hotswap socket position in the PCB. This means that multiple switches need to be north-facing, and some east and west-facing as well. I'm aware that this is not a perfect scenario and some issues may arise with some keycaps plus switch combinations. However, this is a common practice nowadays in many keyboards and personally, in my limited list of keysets, I never had any issues. Nevertheless, I tried to minimize the existence of "side-facing" switches at maximum and the last tests leave me to conclude that only two "side-facing" switches will be present when using ANSI or ISO layout.

I'm currently doing some internal tests with the first round of prototypes. I've already identified some areas for improvement, and I believe now is the right moment to hear more feedback from you guys. It would be wonderful if you folks could share if, first, you would like to see this going mainstream and secondly, if you would like to see anything else supported. Please also feel free to share any concerns that you may have, so I can incorporate that feedback in the next versions.

Price

For the price, I believe it is possible to achieve the target of 55€ per PCB if a MOQ of 50 is achieved. If the order number reaches 100 units or more, maybe we can drop the price to 50€. These prices aren't 100% final and are just an estimation considering prototype costs and my quotes/maths.


6. Credits and Final Notes

• Portuguese Community — always supportive, good lads.
• Others — I would also like to thank everyone who provided feedback about this project and helped me be in this position now.

I hope you found this project interesting, and hopefully, I can help the community by making this "universal" PCB. As an ISO support, it will be great to see more people playing with ISO layout and TKL boards in general, without the need to buy multiple hotswap PCBs.
I also have other small projects keyboard related (stands, stab testers, etc.) that you can find on my online store. You can also follow this and other projects I create on ClackX Instagram .
Feel free to ask questions and suggest improvements you believe would help the project.
Thanks for having me.

[doctorboy]

IC Changelog

Date	Changes
26/06/2023	Added two new questions to the IC form about the interest of a 6.25u bottom row, as discussed.

[Nascent]

As an ISO user, this is the PCB I've been looking for for a while. Count me in for at least one for my Frog. GLWIC!

[Pup]

ISO ftw! Completely support your initiative!

[Rafa_n]

Cool project, hope this hits MOQ.
 -FF

[phatmasterq]

what a great idea, and big respect for taking it upon yourself to bring this to the community. GLWIC!

[aicyborg]

Is this for sure Frog TKL compatible and with other Geonworks TKLs? I understand that the flipped HS sockets on the bottom row mean it in theory isn't.

I ran a small GB (<50 units) for a similar thing to this but ISO only in order to avoid the sideways sockets problem and we had to keep a fixed 7u (1.5, 1, 1.5, 7, 1.5, 1, 1.5) bottom row in order to be compatible with Frogs and other Geon boards. (Discord link, need to be in Geon's server.)

Regardless of the above, as an ISO diehard too I'm really happy to see this. Good luck!

[VXQN]

The specs on this PCB are really great — dual DB compatibility is remarkably considerate!

Only including the scroll lock LED is an unusual choice though, considering how deprecated that function is. If it were me, I'd either remove it, or maybe swap/add an ESC LED?

[doctorboy]

As an ISO user, this is the PCB I've been looking for for a while. Count me in for at least one for my Frog. GLWIC!

ISO ftw! Completely support your initiative!

Cool project, hope this hits MOQ.
 -FF

what a great idea, and big respect for taking it upon yourself to bring this to the community. GLWIC!

Thanks a lot for your support. It means a lot to me. 

Is this for sure Frog TKL compatible and with other Geonworks TKLs? I understand that the flipped HS sockets on the bottom row mean it in theory isn't.

I ran a small GB (<50 units) for a similar thing to this but ISO only in order to avoid the sideways sockets problem and we had to keep a fixed 7u (1.5, 1, 1.5, 7, 1.5, 1, 1.5) bottom row in order to be compatible with Frogs and other Geon boards. (Discord link, need to be in Geon's server.)

Regardless of the above, as an ISO diehard too I'm really happy to see this. Good luck!

Thanks for raising this topic. I was not aware that Frog TKL had such low tolerances in the bottom row. I do have access to a couple of Geon boards (but not Frog specifically) so I will make some tests on my side that I would share before GB moves forward (if it goes forward, of course).
It will be a shame if we reduce the allowed bottom row options because that is one of the key factors of this PCB. However, what we can do maybe is to have a variation of the PCB with a fixed tsagan bottom row.
Do you guys think that would make sense?
It will make things harder in terms of price (MOQ might be more challenging) but it is a possibility.

The specs on this PCB are really great — dual DB compatibility is remarkably considerate!

Only including the scroll lock LED is an unusual choice though, considering how deprecated that function is. If it were me, I'd either remove it or maybe swap/add an ESC LED?

Thanks for your feedback. I know LED in the scroll lock is not a very popular choice. My original plan was also to include the caps lock LED, but as I said in the original post, it is not possible due to supporting the stepped caps lock. One option is to remove the LED completely if folks think this would make more sense.

[GMKClassicRed]

Would you offer the PCB plain but solid colour, like all red?

[doctorboy]

Would you offer the PCB plain but solid colour, like all red?

Can you please clarify what you mean by PCB plain? A version without the top silkscreen and only with a solid colour? If yes, yeah, that is a possibility. If you don't mind, please add that info via the IC form (I have questions about the silkscreen design and the preferred colour), it will be easy for further analysis.
Thanks!

[aicyborg]

Is this for sure Frog TKL compatible and with other Geonworks TKLs? I understand that the flipped HS sockets on the bottom row mean it in theory isn't.

I ran a small GB (<50 units) for a similar thing to this but ISO only in order to avoid the sideways sockets problem and we had to keep a fixed 7u (1.5, 1, 1.5, 7, 1.5, 1, 1.5) bottom row in order to be compatible with Frogs and other Geon boards. (Discord link, need to be in Geon's server.)

Regardless of the above, as an ISO diehard too I'm really happy to see this. Good luck!

Thanks for raising this topic. I was not aware that Frog TKL had such low tolerances in the bottom row. I do have access to a couple of Geon boards (but not Frog specifically) so I will make some tests on my side that I would share before GB moves forward (if it goes forward, of course).
It will be a shame if we reduce the allowed bottom row options because that is one of the key factors of this PCB. However, what we can do maybe is to have a variation of the PCB with a fixed tsagan bottom row.
Do you guys think that would make sense?
It will make things harder in terms of price (MOQ might be more challenging) but it is a possibility.

For the small GB I mentioned we chose to stick to 7u/tsangan bottom row on the basis that's what other compatible PCBs are, like Gondolindrim's HS ANSI board with the long name. In my opinion not many people use 6.2u bottom row for a TKL form factor - but I appreciate that you really want tons of flexibility and compatibility options here. I'm honestly not sure about it myself. In my case I just figured since existing designs didn't support it there was probably a good reason why, though we didn't investigate specifically.

Might be worth adding an IC question to see who builds 7u vs. 6.25u bottom rows, to help inform you here?

[doctorboy]

For the small GB I mentioned we chose to stick to 7u/tsangan bottom row on the basis that's what other compatible PCBs are, like Gondolindrim's HS ANSI board with the long name. In my opinion not many people use 6.2u bottom row for a TKL form factor - but I appreciate that you really want tons of flexibility and compatibility options here. I'm honestly not sure about it myself. In my case I just figured since existing designs didn't support it there was probably a good reason why, though we didn't investigate specifically.

Might be worth adding an IC question to see who builds 7u vs. 6.25u bottom rows, to help inform you here?

Thanks again for your feedback. I tried to check if I could have only the 6.25u bottom row with the north-facing hotswap sockets, which would facilitate price-wise, but unfortunately is not possible. My temptation is to have two versions, one with a 7u bottom row only where the bottom row switches are all as south-facing, and another one with more compatibility (the 6.25u) but including north-facing switches as well. This way, the folks that are concerned about tolerances on the bottom row would have a more safe choice to go with. The main disadvantage will be affecting the price.
I've added two more questions to the IC so that people can manifest if they are interested in a 6.25u bottom row and with which boards they are planning to use this PCB.

Thanks, everyone, and let's see if we can make this happen.

[Nascent]

Filled the IC Form. I personally wouldn't mind paying a little extra to have a 7U only bottom row to avoid any possible tolerance/interference problems caused by the north facing sockets

[aicyborg]

For the small GB I mentioned we chose to stick to 7u/tsangan bottom row on the basis that's what other compatible PCBs are, like Gondolindrim's HS ANSI board with the long name. In my opinion not many people use 6.2u bottom row for a TKL form factor - but I appreciate that you really want tons of flexibility and compatibility options here. I'm honestly not sure about it myself. In my case I just figured since existing designs didn't support it there was probably a good reason why, though we didn't investigate specifically.

Might be worth adding an IC question to see who builds 7u vs. 6.25u bottom rows, to help inform you here?

Thanks again for your feedback. I tried to check if I could have only the 6.25u bottom row with the north-facing hotswap sockets, which would facilitate price-wise, but unfortunately is not possible. My temptation is to have two versions, one with a 7u bottom row only where the bottom row switches are all as south-facing, and another one with more compatibility (the 6.25u) but including north-facing switches as well. This way, the folks that are concerned about tolerances on the bottom row would have a more safe choice to go with. The main disadvantage will be affecting the price.
I've added two more questions to the IC so that people can manifest if they are interested in a 6.25u bottom row and with which boards they are planning to use this PCB.

Thanks, everyone, and let's see if we can make this happen.

Arguably at that point you may as well just split it to two SKUs: one with a fixed 7u bottom row and the other with a fixed 6.25u - it's not like someone could use a bit of one and a bit of the other.

That said I think you're right to be very price-conscious, though also think you should test with a few Geon boards. Geon makes a pretty big amount of the hobby's TKLs (at least the ones consistently in stock and thus likely for people to own). I have a Frog TKL and would be happy to test this for you but I'm in the UK, so I assume you can probably find someone closer!

[AmethystDCVR]

Arguably at that point you may as well just split it to two SKUs: one with a fixed 7u bottom row and the other with a fixed 6.25u - it's not like someone could use a bit of one and a bit of the other.

i use the outer 2 1.25u ANSI layout mods with 1.5u WK layout alts and 7u space. so for me a pcb that supports both is my pref, but my use case is a extreme minority

[ppatches24]

Such an awesome project and im ready to buy a few. I really hope this gets made as this is the perfect PCB im looking for!

Thank you for making this and I hope this becomes a product I can buy!

[doctorboy]

Arguably at that point you may as well just split it to two SKUs: one with a fixed 7u bottom row and the other with a fixed 6.25u - it's not like someone could use a bit of one and a bit of the other.

That said I think you're right to be very price-conscious, though also think you should test with a few Geon boards. Geon makes a pretty big amount of the hobby's TKLs (at least the ones consistently in stock and thus likely for people to own). I have a Frog TKL and would be happy to test this for you but I'm in the UK, so I assume you can probably find someone closer!

Thanks a lot for your suggestions. Most likely what I will do is, as you mentioned, have two different products. More likely it will be one with all the layout options and another one only with a fixed bottom row. However, it is still under analysis.

I've been testing the PCB with a couple of boards, and I'm planning to share before the GB the list of boards where I tested the PCB and where the compatibility is guaranteed.

Thanks everyone for the amazing feedback that I've received.
For everyone that did not have the chance yet to fulfil the IC form, please do. It will help me a lot to make the right decisions. Thanks in advance!

[Nascent]

Any updates?

[Applet]

Did you verify that the ISO enter stab works with that ANSI enter socket rotation?

[Flybeck]

Well done!

Would be nice to see this eventually roll as an in stock product thats available.

<3

[doctorboy]

Any updates?

Thanks for still remembering about this project. No significant progress; I’m currently testing the PCB on some keyboards (mine and from friends) to test the compatibility. We have already identified some improvements that we want to integrate into the next version.
Currently, we are in the holiday season, and I don’t have much time; I will likely pick up this in January.

Did you verify that the ISO enter stab works with that ANSI enter socket rotation?

I can confirm that this doesn’t work. There are also other things that don’t work, but everything will be adjusted in the final version.

Well done!

Would be nice to see this eventually roll as an in stock product thats available.

<3

This is definitely under consideration. If I follow that route, I will be moving forward with a much smaller MOQ, and a price slightly higher. But availability will be in stock. Something still under discussion until the final version.

[shansoft]

Does this support mini USB? It would be great to work on some older board such as Jane v2/v2 CE.

[zlobin356]

the print on pcb looks very cool, the pcb it self is very nice i think. it will be very good, if someone will make an space invader pcb for tkl.