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Quaero

Created by [AlwaysLearning on Slack] • Started on June 22, 2025

A sleek low-profile split keyboard featuring a touchpad module.

Retro Journaling

Similar Keyboards and Useful Resources

Brainstorming and Design Constraints

What I need: - Detachable number row. I want to use either mouse bites or v cuts to make a detachable number row. This way the PCB can be used by people who do not want to use a number layer (like my Dad). - Trackpad. This is a must for Dad, an optional nice (though expensive) feature for me. I do want trackpad support nonetheless. - Optional wireless support. Even though the original build with a trackpad can't use ZMK, I want to make a second smaller one using the remaining PCBs that is wireless. - Low profile. The handwired WordSplitter I'm currently is too clunky for my taste. I want a keyboard I can travel with, one that's sleek. What I want: - Maybe make it so I can add a magnetic plate that unifies the two halves and that can like snap on the top of my thinkpad keyboard, using small extruded rows that match the outline of the thinkpad's keys to reduce wiggling/movement. - Minimal yet sleek design. I really like the Torn and Totem keyboard's designs. Hillside's layout is also very nice, but I do not like the shape of its PCB at all. It just doesn't fit - Probably a vertically positioned USB-C receptacle, so I can potentially bring the splits close together. That will be difficult though, seeing the orientation of the MCU.

BOM

PCB

Example: The Totem's Schematic image This is a great reference. Simple and to the point.

Positioning in KiCAD is hard. Really hard. The best way I've found to move items to create stuff such as column stagger is select a whole column, right click, positioning, position interactively. Then you can select like two identical corners on let's say the pinky column and ring column and create an y offset between them. Work outwards or inwards relative to the middle finger column: so first to create the ring finger column stagger for example set the reference point on the top right corner of the top most switch, and then the relative reference corner on the top right corner of the top most switch from the middle finger column, and then set the offset to like -8.5mm as on the Totem and then move onward. To measure the offset and splay and all of all the different columns and thumbkeys, what I did was import the Totem case top .step file into Onshape, and then I selected two of the vertices of adjacent columns: so like the top right corner of the top switch of the pinky column and the top left corner of the ring finger column. Onshape then has this nice little popup measure menu down at the bottom which tells you the angle, x, y, and z distances between your two selections. You can do something in OrcaSlicer/other slicer programs as well, albeit in a more difficult way (harder to select edges and vertices).

image

Once you have your layout (of the switches) determined in KiCAD, you can start working on the rest of the PCB, as well as the schematic. First, assign to each switch a reference, as shown here. By default, if you haven't already made a schematic (might be easier to just make the switches and the matrix first and then do this, but this is useful if you are using ergogen), make one and start making your matrix. I used Snumber for my reference, as that's the default generation reference that Scotto's placeholder switch uses. It would be better to name them SWRnumber/SWL_number as GeistGeist does in his Totem schematic though, as that way it will be easier to discern. Though that way you might have to manually rename everything in the schematic as well.

image

For the USB-C receptacle I'm using the 4085 THT one. KiCAD has these in it's default libraries, so that's great. It also has the 3D model for it. Speaking of 3D models: instead of using a diode from like ScottoKeebs library, if you use the DO-35 THT 7.62 mm pitch (just like the ammo lol) footprint which is part of KiCAD's default libraries then you don't have to manually assign a 3D model. Here's a great schematic I found on the Scottokeebs Discord. Credit Ben Park. image

After some more research and trying out to figure how to connect both a battery and a usb c to the nrf52840, my dumb ass realized that it doesn't matter because QMK does not support the nrf52840 chip, so I can't make it wired. And as ZMK trackpad support is a mess and terribly complicated, I guess I'll just swap the supermini for a pico, and that's that. I could try and make compatible with both the supermini and the pico, but I'm complicating things too much and I don't have that much time left, so yeah.

Okay did some more research and talked to some guys on the Discord, and turns out that some RP2040 boards (which are compatible with QMK) have the same layout/similar pinout to the SuperMini NRF52840 such as these: keycapsss, aliexpress (tenstar), and keeb.io. I'm worried about the pins needed for I2C though, as their placement might differ between the two if they are placed at the very bottom. Oh by the way, I got this from bkendall's repo for RP2040 MCUs, which he kindly shared with me on Discord. Power Switch options Also the battery pins in the upper left corner seem to be joined in the marbastlib footprint for the nrf, but they aren't for the rp2040 pro micro, so that might be an issue. I think that I'll have to remove the pin header for the second pin for the rp2040 to prevent any issues.

image image

Rough Estimated Time: 30h Researching every part was a pain.

4/07/2025

Time Spent: 3h 10m image

Redid the board routing. I used 15.75 mils trace width for the power, and even though I tried to avoid it I had to use one via on the trace from the +3.3V from the OLED to the MCU. For some reason the outlines of the teardrops used in my past version of routing are still there (look right beneath the MCU), but I can't seem to remove them and they dont't seem to do anything so I'll just ignore them. I now realize that instead of spending time adjusting the column and row pins in the schematic it would have been much easier to just not assign any pins of the MCU, route the matrix, and then assign the pins depending on how and where I could draw the traces. I also re-adjust the cutouts a bit, and did research on those as well as asked in the Keyboard Atelier server. Unfortunately, there aren't many keyboards with these kind of cutouts. I did find some in the Corne v4 and Hillside (admittedly for columns, not rows, but it should be pretty much the same thing). Someone on the Discord reminded me that if I plan to cut the material between the cutouts out with a Dremel than I need to make said distance at least as large as the disc of the Dremel, which I did not think about before. So I double-checked the distances to make sure there isn't anything that would be too difficult to cut. You'll notice that for I left the gaps between cutous larger in two spaces. This is because I want to see if bigger pieces are that harder to cut. If they aren't, I'll use a similar distance in the future because I have more space to route stuff + the PCB will be stronger. Speaking of the PCB, the same person who reminded me of the disc size also told me that dust from cutting PCBs is toxic, which I had totally forgotten, so I'll have to make sure I remember to use a mask when doing so.

image I've also started messing around with ground fills, but I have absolutely no idea what I'm doing. DRC error check says something about thermal relief, so I'll have to check that in the future.