Day 4: Finished Routing Left Half

I attempted to finish routing the row and column matrix to my MCU. I had thought that this would be the easiest part since it was already set up in rows and columns. However, I placed my components in bad spots when setting up the PCB, so I had no room to route my last few traces. I spent about an hour trying to get my last few traces done when I gave up and decided to restart, as I also had a lot of islands on my ground pour. This time, I paid attention to the ratlines to choose better spots to place my components. I began by routing the columns and rows to the MCU, then the small parts, and finally the columns and rows together. This approach was much cleaner and made it very easy to route compared to my first run. After a few hours, I finished my routing for the left half.

Day 3: Redid Everything

EasyEDA decided to delete my whole project for some reason, I'm guessing it was because I haven't worked on it for a while. I was unable to find it online or on the desktop EDA, so I just assumed it had been deleted. I decided to restart, following the ZMK design guide again. However, since I was no longer limited to the selection of parts from Grounded, I decided to make it a 60% keyboard this time to add more functionality. Most of the schematic was the same from last time, as it was just power and some selection circuits, which are generic to any keyboard. The only difference between this schematic and my old one is the number of switches and neopixels I have, as it is now a 60% split. I also decided, while placing my components, that I didn't like the mid-mount USB C, so I swapped it out for a regular top-mount USB C connector which didn't take up as much room. I also added some stabilizers for some of the larger keys that come with a 60% and 4 mounting screws. This is my final schematic for the left half:

Placing the components is what took most of the time. Usually, this part is pretty quick compared to the schematic, as I usually use separate MCU boards, which saves me most of the routing. However, this time, since I decided to use just the SoC, I had a lot more components to place and a lot more routing to do. I first placed the switches, followed by the neopixels, and then the diodes and capacitors. Then I placed all the parts for the MCU, placing the related parts together to ease routing. This process alone took me around 2 hours since the board was very small. I also made a few changes to the components I used, although the overall design is still the same (eg, I swapped a switch out for another switch). Finally, I began routing the PCB. I started with all the MCU connections, as those were the hardest and most important. One good thing about EasyEDA is that it has a differential pair routing tool, so I was able to easily make a set of well-routed data lines. Finally, I began routing the switches and neopixels, as I saved the easiest for last. I have finished routing the neopixels and need to finish the switches. This is my PCB so far:

Day 2: Added switches and RGB

Today, I added the switch matrix and RGB. I imported the marbastlib library, which I have used in the past, and used the choc and SK6812 mini footprints. I began by looking at a model of a 60% keyboard online and splitting roughly along the center. This is how I split it:

I decided to begin with the left half. I first added the 49 switches I would need and arranged them in a 7x7 matrix to save on GPIO pins, as I usually run out. However, I did realize after finishing that I would have many GPIO pins left. After making my matrix and wiring the columns and rows together, I moved on to the RGB underglow. I connected each DIN pin to the DOUT pin of the previous SK6812 until I had 49 LEDs. I then connected these to a data switch that I copied from the ZMK design Github. After I was done, this is what my schematic looked like.

I selected the footprints to get ready for PCB creation. Next, I need to place and route my components on the actual PCB and design the case once I get my main laptop back.

Day 1.5: Redid work from Grounded

I started this project back when Grounded was running and intended it to be a 40% keyboard due to parts limitations. However, now that blueprint has a very high budget, I have decided to make it a more usable 60%. In doing so, I completely scrapped my ~1 hour of work that I spent on it during grounded.

I decided to follow the ZMK design guide to get started, as I have never made a keyboard before without a pre-made MCU (like a nice!nano) and didn't want to mess it up. The guide provided clear examples and was meant for ZMK keyboards, so it fit my project well. I also decided to do it in easyEDA this time since I didn't have my personal laptop with me. I started with the USB, something that I have always had trouble with. However, the guide made it simple and I ended up with this rather hard-to-read circuit:

One of the good things about using easyEDA was its tie-up with JLCPCB, so I could easily pick parts that I could be sure were available for PCBA. Once again following the guide, I created the charging circuit and the main MCU circuit. I decided to use the HolyIot MCU since I couldn't find the other ones online. This is what I ended up with:

Now, all I have to do is the actual switch matrix as well as some small circuits for RGB.