The base of the keyboard can take a variety of shapes and sizes. The one that I decided to go with is a bit of a strange design, but it is one that I was drawn to. I would recommend that you go out on a search for a design that you like and get yourself something that you would love to look at on your desk.

This is probably the most important part of the build since everything else is going to go on top of it. The design should be something that you feel will be comfortable to type on. The Dactyl design is one that I felt would be more ergonomic given how much I use my keyboard.

Aside from the design, you will want to decide now how many keys you want the keyboard to have. My choice has 34 keys on each half. A total of 64 keys will be necessary for the completed board. There are many designs out there, and each has their benefits.

I decided on the Arduino Pro Micro for this build. Between the different forums I visited, and various builds from others, it seemed that the Pro-Micro is already capable of working with QMK (Open Source Keyboard Software). Another reason for going with this microcontroller is that these are relatively inexpensive. They have been around for some time and have many documents available in case I ran into any troubles.

Thankfully, I did not run into any issues during the project even though I used a knockoff brand. That doesn't necessarily mean that you won't. I would usually go with a legitimate product but the stress in the supply chain during the pandemic made it a bit more difficult to obtain.

Assuming you get the same microcontrollers that I did, you will need to wire your own reset switch to the body of your build in some way or another. It is either that route, or everytime you need to flash the firmware, you will need to short the ground and reset pins on the MC. I would recommend taking apart your old devices that no longer work, or something you can use for parts, and get some tactile switch out of it. I have done this for most of the switches I have, but I also have some nice ones that came with an arduino uno kit. However you want to move forward, I suggest you plan for this ahead of time as I did not. I only realized after having printed my frame and gotten started with soldering. Thankfully, I did not do any damage to my parts and I was able to add a reset switch to the system.

Note: You will only need one reset switch if you are using the two in a master/slave system. This will not be sufficient and you will need one on each if you plan to work them as separate devices; each connected to the PC.

There are two different types of wire that were used in the build. The first is the obvious USB cable for connecting to the computer, and the second is used on the inside of the keyboard. The wire inside does not need to be beefy as it is not going to be carrying a lot of current. Any wire that is easy to work with and pliable is preferred. I used some 24 AWG stranded silicone wire because of the pliability and cost. I picked up some of this wire on Amazon for about 10 dollars. It came in 6 colors and 5 feet of each.

Note: I am fairly confident that any wire would do for the internal connections. I think a good place to find some would be some old networking cables that could be repurposed. Since they are typically 5 or 6 core, you should have plenty of different wires to choose from.

The next piece of the process will have us working to create the keymap.

The process for creating a new map is fairly straightforward. We need to open up a command prompt or terminal to create our new keymap, and use the following command:

qmk new-keymap

This command is all that is necessary, or you can use the following if you have multiple keyboards:

qmk new-keymap -kb <Keyboard_name>

This one allows you to specify which one you are going to be using. After the command is processed, you should see a new keymap.c file at the location provided by the CLI. Open up that new keymap.c file and take a look at its contents. The list of layers that you have on your keyboard firmware at the end of the process begins at the keymaps array. The array is of type const uint16 and has the following definition:

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS]

This is where we need to make the changes to add more layers to the keyboard. You can add many different types of actions to the array by adding in the keycodes. These can be basic codes, quantum codes, and even mouse presses. No matter what your fancy is, you are sure to find something that you like.

Note of Caution:

While you are just getting started, it would be wise to keep your changes small to minimize any errors that you may introduce.

Congrats! We have come a long way and are nearing completion. The last command needed is:

qmk compile

After the command is complete, you should see the following or similar in the window:

Linking: .build/planck_rev5_default.elf [OK]

Creating load file for flashing: .build/planck_rev5_default.hex [OK]

Copying planck_rev5_default.hex to qmk_firmware folder [OK]

Checking file size of planck_rev5_default.hex [OK]

* The firmware size is fine - 27312/28672 (95%, 1360 bytes free)

If you did not configure your environment, or you have multiple keyboards, you can specify a keyboard and/or keymap with the following:

qmk compile -kb <keyboard> -km <keymap>