Another keyboard build!
This time its Bluetooth with an integrated macropad.
Why you may ask? Well I’m returning to campus Fall 2021, and I want a portable keyboard that feels as good as my recently build ROMEO 40%. Best part? Since it’s Bluetooth maybe I can connect it to my iPad!
First I’d like to thank Hadi and their great series on making a mechanical keyboard from the ground up!
https://www.youtube.com/watch?v=BhFqkVggv8Q
Step 1: Layout! What kind of board are we making??
I’m starting with a modified Planck layout, excluding the normal layer shifts for a split style space bar (for later macro functionality if needed) and an integrated macropad. I’ll use this for my SSH & login macros, as well as some commenting macros I for block comments in C.
The board will be built on the BTE enabled development board based on the Micro-Pro pinout, the nice!nano: https://docs.nicekeyboards.com/#/nice!nano/, and configured through ZMK
http://www.keyboard-layout-editor.com/ is a FANTASTIC layout tool for this. When combined with my next listed tool, we can easily create custom PCBs without measuring and designing our actual layout by hand.
I discovered this tool when creating the template for my (WIP) macropad.
Step 2: Starting the schematic
To get an actual layout from keyboard-layout-tool, I copied the raw data (which you can see in the pic above) into http://builder.swillkb.com/ , which is another fantastic tool.
From this, we get not only the layout for the eventual metal plate, but also the basis for our PCB. No more handwiring! Just copy the above raw data into the “plate layout” section and select switch type. Since I plan on using normal switches, I just went with MX {_t:1}.
We want to download the DXF here to use in Autodesk (thank you academic licenses).
After about 30 minutes in Autodesk, we have a calibrated layout with center pinholes to import into Eagle. We’re about to start the actual PCB!
Step 3: Soaring like an Eagle (through PCB Layout)!
Now we’re getting into the real fun part! This may take a bit more work and planning now instead of hand-wiring, but not only is the method easier to plan out, we can also make a lot more of these boards (not that I foresee demand, but who knows?).
Now with switches placed we can lay down the diodes and connect the nets:
First we need to add the switch layout. The assorted macrokeys are labeled with M# for now.
I’m not sure on the PCB design itself yet. I will be using a transparent acrylic case, so the design has to be clean and interesting. I’m thinking classic black PCB with golden inlay. Red could also be interesting though.
Step 3 (again): Big update!
After running the PCB design through JLCPCB, the cost to do SMD diodes was too prohibitive, so I’ve redesigned the board for through-hole diodes.
To accommodate, through-hole diodes, the board’s size was increased slightly on all sides.
This allows for a neater diode-nest, which can be seen in the bottom right.
A refinement for the future (probably next update) would be to reverse the order for diodes. The path routing here was fairly convoluted, save for the last row which was reversed. Reversal allows for the rightmost key to be associated with the leftmost diode, enabling very short routes without blocking the remaining routes.
In the upper right, you can see the pin sockets for the nice!nano, which uses the pro-micro pinout.