PCB Guide Part 2 - Beginning the project
By this point, you should have a repository readied for the project.
Step 3. Creating the KiCad project
The previous page's setup should have created a folder in your home/Documents/GitHub folder with the project name.
We will be doing all work here.
Launch KiCad, and you will be greeted with the main menu.
From the options, select New Project.
Browse to your repository directory.
Make sure to uncheck "Create a new directory for the project". Otherwise, you will have your project in a useless subdirectory.
KiCad will generate the basic project files.
The default project only has two files:
- The .sch file - Contains the schematic, or the electrical layout. This is where you will add the parts and wire them together, so KiCad knows what you're trying to accomplish.
- The .kicad_pcb file - Contains the physical layout. This is where you take the data from the schematic, and position and connect them all together for production.
The basic workflow is to create the schematic first so that the electric side is all set, then to lay it out on a physical PCB based on that.
At this point, let's commit our changes.
Give the commit a name, commit, and push the changes.
This guide will occasionally remind you to commit after large milestones; however, it is recommended to do so often. Losing work is not an enjoyable experience.
Step 4. Add local libraries
KiCad is built around libraries - A collection of footprints, and often schematic components bundled with it.
Footprints are the building blocks of PCBs - The sets of copper pads that the components attach to.
KiCad ships by default with support for common electrical components, such as resistors, capacitors, microcontrollers, etc.
It does not ship with exotic things, such as Cherry MX footprints, very specific USB connectors, etc.
Let's take care of that.
KiCad supports two library install types:
- Global - The library is added to the computer. This means you only have to install the library once.
However, this has the massive downside of requiring that the library be installed to view the project on another computer. This can be a hassle, especially if having the project checked by others
- Local, or Project-Specific - The library is added only for the specific project. This means you will have to install the library each time; however, the project can be shared instantly without any worry about compatibility or missing libraries.
We will be using project-specific libraries.
First, we will need to pick which footprint libraries to use.
In this guide, I will be making use of the following repositories:
- My MX-Alps hybrid footprint library - For switches.
- My random keyboard parts library - Mainly for the USB connector.
We will be adding these to our project as Git Submodules - This allows us to pull new changes from them without having to manually download and overwrite the existing files.
Since the GitHub desktop application is fairly awful at managing submodules, we will opt for using the shell instead.
Then, run the following command:
git submodule add URL-OF-REPO
In this case, I will add the two repositories linked earlier.
The GitHub desktop GUI seems to have issues with committing submodules, so let's do it from the command line:
git add *
git commit -m "Add submodules"
The commands adds the new submodules to the commit, creates a commit with the given name, and pushes it to GitHub.
After the push finishes, you can see that the library repositories are linked in your GitHub repository.
Now that the files are there, let's add them to the project.
First, open up your schematic file,
Select Preferences -> Manage Symbol Libraries,
Select the Project Specific Libraries tab, select Browse Libraries (Folder icon),
And select the .lib files in each of the added libraries.
After checking that both are added, confirm the changes by pressing OK.
Close the schematic editor for now.
Open the PCB file,
Go to Preferences -> Manage Footprint Libraries, switch to Project Specific Libraries, and browse for the added .pretty folders.
For this guide, I will be using the MX_Alps_Hybrid style footprints.
Again, click OK to confirm changes, then close the PCB editor.
Commit these changes, and push the commit.
If both the fp- and sym-lib-table files are not showing up, make sure you hit OK when adding the libraries rather than simply closing the dialog.
Now you're all prepared for making your first keyboard!
Time to begin the schematic.