HalfMoon Keyboard

Finally finished my custom keyboard. My primary inspiration was the Atreus62 keyboard. I did some testing with layouts using my Prototyping keyboard and found that the offset on the Atreus keyboards seemed a bit severe to me. Maybe it's just me but my middle finger doesn't seem to need to be that much higher that my other fingers. So, I went with an ErgoDox vertical offset which is closer to straight ortho. But I didn't really want to go the split route so kept the non-split and angle of the Atreus. Eventually I saw some other custom layouts where the outside columns for the pinky fingers were offset farther down and that made some sense to me. Finally, I liked the idea of a thumb cluster so I can use my thumbs for more things. I liked the arched ones that some people have used and added that as well. Originally, I was looking at more of a 90 degree arch that I had tested with and liked. But, I like the way this layout comes together with the key in the middle and it keeps things a little more compact. I would like to make a smaller version of this keyboard that keeps the same thumb clusters. So, this was my compromise.

This was my first custom PCB. This is showing the top/switch side. I don't have anything on the bottom as I wanted to keep things as thin as possible. I also didn't want to use surface mount components as those are a little harder to deal with. In order to keep the PCB simple, I decided to use a Teensy 3.2 for my controller. But again, to keep the whole thing slim, I mounted the Teensy flush with the PCB instead of using the normal pins to connect them. I used the leads I clipped off the diodes to connect the PCB to the Teensy. Last, I tried to make the PCB universal for MX, Alps and Kailh low profile switches. I used an existing MX/Alps footprint from EasyEDA and added the additional pin locations for the Kailh including the click-bar wire that sticks through the bottom of the switch. I did make one mistake though. The Kailh low profile switches use a slightly wider spacing for the PCB supports on the side. So the switches won't fit unless you cut off the supports. I'll have to include this with a few other minor updates in my next PCB.

Switches are mounted in the plate and soldered to the PCB. Instead of using the USB header on the Teensy, I used a breakout board. The mounting holes on the breakout board give some good support to prevent pulling on the pins/wires. I also decided to try out USB-C for this board. I did a bunch of reading on what you are supposed to do when using USB-C connecting to a USB2 device. But I wasn't exactly sure what I was supposed to do. So, I kept it simple and just connected the Vcc, Gnd and D+/- straight through. I'll be using this with a USB A-C cable so none of the other pins will be used anyways. But I would be concerned about plugging this into a USB-C connector on a PC. The unfortunate thing is that this breakout board has been discontinued and can't be found anymore. So, I'll have to redesign my layout around a different breakout board for next time. None of them seem like that will work as well as this one at this point.

Added the 5.6mm acrylic middle layer with the spacers fit in there nice and tight. I'm glad everything worked without any major issues.

I'm not great at wood-working and finishing but I'm happy with the result. The plate is two layers of 1.5mm birch plywood. This actually is pretty sturdy. I made one hand wired keyboard with a 1mm steel plate that was very sturdy and one hand wired keyboard with a 1.5mm + 3mm plate that is not sturdy. This keyboard is a good middle ground. The PCB probably helps as well compared to hand wired. Switches are MOD-M that I silenced using liquid latex. I did this with some Gateron browns as well and it's held up pretty good so far with those. Although I'm excited to use Zilents for my next build. Modding these was a lot of work.

The layers are 1.5mm plywood + 1.5mm plywood + 5.6mm acrylic + 1.5mm plywood for a total of 10.1mm. I used small/thin screws as well so my feet are also very thin. The whole thing is very low profile. My original plan was to use 3mm acrylic for the bottom thinking I would need it to make it sturdier. But that was unnecessary. The bottom plate is currently just another top layer that I had around. So, you can see the PCB through the switch mounting holes. I'll have to get a new bottom plate cut at some point but it's not high on the priority list.

Here's the USB-C port which fits very nicely in through the middle layer of the case.

Here are the DXF files used for the case...

Here is the PCB layout...
Unibrow V1 @EasyEDA

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