r/HandwiredKeyboards

Hi All,

I feel like I've exhausted all the documentation and videos I can find on the subject and don't know where else to turn. Here's my set up

Split keyboard that is asymmetrical. Both sides have 5 rows and 7 columns. I have an pico on each side.

I used POG (shoutout to Jan Lunge) to install KMK and configure the halves. I can get both sides to work and type when they are connected independently. However, when connected together, I can only get key presses to register via Serial console for the left side, but the right side does not register key presses in the serial console.

Both sides are connected with jumper wires right now as follows on the pico

Pin 40 - VBUS

Pin 38 - GND

Pin 0 - TX

Pin 1 - RX

Here's the snippet of code for the split portion

self.split = Split(

split_side=side,

split_target_left=pog.splitTargetLeft,

split_type=SplitType.UART,

data_pin=board.GP1,

data_pin2=board.GP0,

use_pio=True,

split_flip=False,

uart_flip=pog.splitUartFlip)

https://preview.redd.it/5724gvydm61h1.jpg?width=1539&format=pjpg&auto=webp&s=e806d47f064af3bdf8072810d651bfce6bbda53a

I’ve been working on a project called QMK Nexus.

While building my own split keyboard with QMK Firmware, I kept having to jump between different tools and docs just to get a working setup. Laying out keys, building the matrix, mapping keycodes, configuring features, and generating firmware all felt more fragmented than they should have.

So I started building QMK Nexus.

The goal is to have one place to design and configure QMK keyboards, especially for hand-wired and custom builds, without having to edit firmware files every time you want to make a change.

Current features include:

• Visual keyboard layout tools
• Matrix generation and mapping
• Keycode configuration
• Support for split keyboards
• OLED, rotary encoder, and trackball configuration
• Database-first architecture that makes adding new functionality easier
• Support for many existing QMK keyboards

One part that works well is the workflow for advanced hardware features. You can set up things like encoders and OLEDs visually, instead of digging through firmware code and documentation.

This started as a tool for my own Cosmos split keyboard, but it’s grown into something bigger.

It’s still a work in progress. I’m looking for feedback from people who are deeply involved in the keyboard or QMK ecosystem.

• What part of QMK setup is most frustrating for you?
• What tools or workflows feel missing today?
• What would make this useful enough to become part of your regular workflow?

If you’re building fully custom or hand-wired boards, I’d especially like to hear from you. That’s the main group I had in mind when designing this.

You can check it out here:
QMK Nexus

If you want to test things or have feature ideas, let me know.