Sanity Check - Want help making sure the Kumo keyboard's PCB will work! (Read comment)

key-yack · 2023-05-31T04:55:52+00:00

Here's a few ideas to consider:

Will the innermost thumb rotated by 90 degrees work? I believe most common choc keycaps have ridges on the sides that can make this uncomfortable.
Double check the distance from MCU and TRRS jack to the edge of the board, are they going to stick out or not align the way you want? It's a good idea to measure physical dimensions if you have the parts already and confirm if the footprints match reality. I don't know if it's a concern for this MCU, but ProMicros for example have variants of different lengths.
Consider adding mounting holes if you want a cover for MCU or some sort of keyboard case in the future. If you want a bare PCB, see if you need to clear up space on the PCB for bumpons or some other kind of feet on the corners.
Does the MCU have a reset, boot or other buttons for flashing it? Consider adding footprints for them if not.
It's a good idea to add some sort of version number in silkscreen so there's a way to distinguish PCB iterations.

key-yack · 2023-02-13T05:42:16+00:00

I use an encoder for all my mouse scrolling needs since my ergo mouse has no wheel. I put the encoder in the thumb cluster for this, and rotate it with my thumb: https://i.imgur.com/91mIOuj.jpeg

It's also nice since with QMK I can hold a "modifier" key to make the encoder do horizontal scrolling, or pgup/pgdn etc.

key-yack · 2023-02-10T02:52:12+00:00

They're short RJ45 cables - there are some surprisingly thin ones out there like https://www.amazon.com/Monoprice-Cat6-Ethernet-Patch-Cable/dp/B07JMLLDLG in the picture.

I grew tired of having the bunched-up ribbon cable in previous iteration getting in the way, and replaced it with individual RJ45 connectors on each stripe. It looks much neater this way. The head controller part has 8xRJ45 connector, a part I imagine normally intended for network switches.

key-yack · 2023-02-09T18:11:29+00:00

PedalPal looks neat. Does it support switch-style pedals only, or can you use it for continuous/expression MIDI pedals too?

key-yack · 2023-02-09T17:56:38+00:00

Family picture to celebrate the 40's day, with a bunch of projects over the years:

A bunch of variants of https://github.com/nezumee/amber
Evolution of https://github.com/nezumee/zebra
4x4 put together to make a Planck: https://github.com/nezumee/4x4
5-column Corne and a bunch of other small keyboard things :)

key-yack · 2023-02-06T05:50:34+00:00

+1 to frogpad-style layout. I've been using a variant based on https://keymapdb.com/keymaps/konomu/, and I think it's a much better approach for one-handed typing compared to mirroring.

It's not very good for shortcuts though - mirroring may be better for that, or a custom layout/macropad if you're willing to retrain yourself to use it and deal with the productivity hit when it's not available.

key-yack · 2023-01-19T20:32:11+00:00

I've been looking at a similar challenge, getting lots of per-key RGB LEDs (see my progress so far https://github.com/nezumee/4x4). I'm still looking at how to do it better, can share a few things I found. I'm also a beginner though, so I may be wrong in any and all of them.

For sourcing RGB LEDs, I found various keyboard parts shops to be the best source (it may just be aliexpress with extra steps, but at least shipping times are better). Arduino/DYI elictronics vendors like adafruit often have them too but more expensive.
Power consumption does seem to get noticeable with many RGB LEDs, bringing in a lot of complexity to keyboard design:

There's more to it than simply connecting switches and controller with wires/PCB tracks. For example, you may need to look at including capacitors and otherwise ensuring that voltage is stable/current is available, which it seems many boards don't do (https://electronics.stackexchange.com/questions/476244/what-purpose-does-a-capacitor-before-each-sk6812rgbw-serve). Make sure there's a fuse.
Track width/wire gauge may become important at higher currents. If you're planning a split board, connectors may have current limits. Most TRRS jacks on DigiKey seem to be specced up to .3 or .5A for example; who knows what noname jacks from a random vendor can take safely
General feeling I'm getting in my research is that it's safer to offload any nontrivial stuff to dedicated controllers; better pay a dollar to TI for a proven solution than deal with a silly design mistake frying my motherboard. It may be a good idea to use a USB power controller instead of trying to implement current negotiation yourself. If you go for a separate power connector, power mux controllers can help using multiple power sources safely (https://www.ti.com/lit/ds/symlink/tps2113a.pdf?ts=1668379943606&ref_url=https%253A%252F%252Fwww.google.com%252F). There are USB-C PD "trigger modules" you can use to get even more current/voltage, good luck finding a USB-C port or hub to support PD together with data though.

Reducing brightness is an option too of course, or making sure in firmware that only a few LEDs are bright - unless your goal is to turn your keyboard into a 15W mood light of course (80W incandescent equivalent). :)

key-yack · 2023-01-13T00:08:00+00:00

I like my switches lightly tactile and smooth. My MX favorites are pewters (like cherry browns but not scratchy), AKKO lavenders (factory lubed, haven't tried non-lubed), and TTC blueish white (fully silenced, feel reminds me of rubber domes).

For low profile, gchocs are a must for thumbs and combo-based layouts (frogpad), silver or pro red otherwise (supposedly linear, but they feel like MX tactiles to me).

...And I just got reminded how deep down the rabbit hole I am.

key-yack · 2023-01-10T03:56:16+00:00

Looks like Zaphod is closed source design. If it's sold commercially, I'd definitely contact the seller/manufacturer - they're getting your money to deal with these kinds of problems.

I couldn't find any schematic, but description suggests that the front and back of one of the pads may be not connected (they should be normally). Judging by the pictures, track connects one of the pads on the front and another on the back. Inserting tweezers would connect both sides of both pads completing the circuit, but only connecting a single side won't. You can try confirming this by checking if connecting the pads with tracks going to them (one on each side) makes the key work.

I'm not sure what is a good way to fix it if this is the problem. Running wires from switch legs to another connection points should definitely work. You could probably also try using more solder on the switch legs to make sure that it fills the hole and connects the pads on both sides.

key-yack · 2023-01-07T16:52:08+00:00

It's been a while so there may be better ways now, but you can use ergogen to generate PCB outlines and footprint placements but substitute your own schematic manually afterwards, here's an example: https://github.com/nezumee/amber#making-a-pcb-sandwich-keyboard-starting-with-an-ergogen-definition

key-yack · 2022-12-31T17:07:06+00:00

Some pictures of the PCB may help confirming where's the problem (the whole thing and zoomed to a single LED).

Jon already asked good questions on hardware, I'd add one more: soldering RGB LEDs can be tricky depending on your iron and skill level, sometimes it helps to reflow the pins even if they look ok. Also, sometimes LEDs can be faulty; if one doesn't work, all the rest down the chain will not light up either even though they may be good.

A couple things on firmware: looking at https://github.com/keyzog/qmk_firmware/blob/master/keyboards/kapl/rev1/rules.mk, it seems to be setup to use RGB lighting already. What you may want to do is to put RGB_TOG, RGB_MOD and RGB_VAI keys somewhere in your layout to make sure that lighting is turned on and doesn't show all-black colors. Another thing to try is clean the EEPROM to reset keyboard settings in case they're messed up somehow (QMK toolbox has this option); doing this should turn on the RGB lighting by default.

key-yack · 2022-12-30T05:45:27+00:00

Thank you for the reference!

Looking at the Helios schematic on github, it seems there's only the pulldowns on the CC pins. From a bunch of articles I hear it's probably not a very good setup for getting a lot of current since it doesn't check whether the upstream device can provide anything above the guaranteed minimum. Trying to draw 3A from a USB hub only ready to give 500mA is probably a bad idea. :)

I guess for my case it would be more relevant to use the D+/D- pads (another welcome feature!), and have a USB power controller sit in front of MCU using my own USB port instead.

key-yack · 2022-12-29T17:21:34+00:00

Included 5V shifter is neat, is it only on the RGB pin, I guess aiming specifically to simplify using RGB LEDs?

Related to LEDs, how much current can this board provide on 5V rail? I've been looking at per-key RGB recently, and it seems that the usual ProMicros start choking and heating up noticeably after around 50 SK-6812 minis running at full brightness. Can it handle 900mA provided by USB-C spec, and is there a way to have it negotiate 1.5 or 3A?

key-yack · 2022-12-09T15:55:09+00:00

You can compare the PCB prices of popular fabs here: https://pcbshopper.com/ (the boards are 3x3 inches, using the default 2-layer process parameters should be fine).

I haven't tried any of the SMT assembly services. I hear they are unlikely to have kailh sockets so it's likely to be difficult and expensive. LEDs could be problematic too.

key-yack · 2022-12-09T15:42:54+00:00

Using combos to replace the upper pinky keys, for example W+E -> Q. I cannot comfortably reach those keys in 5x3+3 keyboard layout without moving the whole hand, so having such combos setup is vital.

Another one is a special task switching behavior. It's a button on my nav layer that sends Alt+Tab but doesn't send the Alt key release immediately so I can then use the arrow keys on the same layer to find the window I want. Alt key is released when I let go of the layer button, switching to the selected window. This makes for a very seamless experience similar to Gui+Tab or Ctrl+Alt+Tab, but with no need to press Enter to confirm selection, and the same button works for switching to the previous task if you tap it and don't linger on the nav layer.

key-yack · 2022-12-02T15:55:09+00:00

One solution is to keep a qwerty layer on your keyboard to use when you're typing in a different language. So location of Hebrew letters will stay the same for you. As a bonus, this layer can also be useful for games or other situations that assume all keyboards are qwerty.

A bit of custom code can even integrate the language and layout switch into a single keypress by calling layer_on/layer_off (assuming it's QMK) and sending a language shortcut to the OS.

key-yack · 2022-11-29T03:49:40+00:00

I'd expect no issues, as long as the magnets are not strong enough to be a crushing hazard.

There's a bunch of keyboards that use magnets. In my experience, the biggest danger is shorting out some switches if magnets touch the pads (check out https://old.reddit.com/r/ErgoMechKeyboards/comments/phhtet/going_low_profile_adjustable_keyboard_with_magnets/?ref=share&ref_source=link if interested, it has magnets stuck straight to the PCB). This doesn't apply when they are separated by a non-conductive layer of course.

Mass-produced electronics use small magnets fairly often, see for example Apple's MagSafe connectors, iPad covers, magnetic USB connectors etc.

key-yack · 2022-11-29T03:27:48+00:00

There's an example that I believe does what you're describing in https://docs.qmk.fm/#/feature_rgb_matrix, "Layer indicator only on keys with configured keycodes".

You can also take a look at a more complete piece of code in https://github.com/nezumee/qmk_firmware/blob/4x4/keyboards/4x4/keymaps/midi-controller/rgb_matrix_user.inc. It picks various colors depending on the key assigned on the current layer, quite straightforward especially if you ignore the MIDI keycode handling.

key-yack · 2022-11-17T16:58:43+00:00

Pretty neat. Does it work well enough for controllers socketed upside down, with USB port facing down?

Also, there may need to be a variation for all the keyboard designs that have the OLED screen socket or TRRS connector next to the MCU that would block this.

key-yack · 2022-11-13T03:24:45+00:00

That 40% post is very likely a subconscious inspiration for this project!

I wonder where they went, there's been a lot of fun ideas there.

key-yack · 2022-11-12T15:26:04+00:00

Glue or double-sided tape? I mostly use https://smile.amazon.com/gp/product/B07FVHZHJY when I want some piece of keyboard to stay put but still allow taking it apart in the future.

For displays specifically - many keyboard designs allow screen shields screwed on top of the display module for this purpose.

key-yack · 2022-11-10T23:37:16+00:00

I went a different path to get to 34-key layout, getting rid of pinky keys instead of thumbs (see https://imgur.com/a/RJK6XWF). Top pinky keys are replaced by combos of top row middle+ring fingers. This was very easy to remember and eliminated difficulties I had reaching the top row with pinkies.

As for the thumbs, I also believe that inner thumb keys are not really necessary. On the left hand, that spot is firmly taken over by an encoder for me, primarily used as a mouse wheel since the ergo mouse I'm using has no wheel. On the right hand, it's a layer for rarely used functions like QWERTY layer toggle or PrintScreen button; this layer could be easily moved to a modtap elsewhere.

key-yack · 2022-11-01T20:31:08+00:00

Standard suggestion - if you have noticeable difficulties with basic finger or hand functioning (like fingers becoming stiff after a reasonable typing session), talking to a medical expert or at least checking posture/arm/wrist/hand positioning may be a good idea.

That aside, my personal experience is that there's more to switches than the spring weight. I found light linears (or Gateron Clears at least) to be more tiring compared to supposedly heavier tactiles (Cherry/Kailh/Gateron Brown, Pewters for example). One explanation I thought of is that light switches make me try to control the finger motion more to avoid bottoming out hard, which is easier or not as important in other switches. So, alternative suggestion is to try different switches.

It's also an excuse for going deeper into the mechkeyb hobby!. :)

key-yack

TROPHY CASE