Custom Circuit Boards

• What shape do you want your circuit board?
  • For us, we wanted a fat gator that could be a key chain
• What do you want the circuit to do?
  • For us, we wanted the eyes to light up when a switch is toggled
• Sketch your basic circuit to determine the essential components you will need to include on your board
  • For us, we wanted a switch, a resistor, a battery and battery pack, and 2 LEDs
  • There are some great programs you can use for free to test your circuits! Like tinkercad.com,

1. Take a photo of your 1:1 scaled drawing
2. Import the image into inkscape
3. Use the pen tool to draw stroke lines over the outer lines of your image, and the node tool to smooth out the lines. Make sure your fill is set to “none”.
4. Delete the image behind your lines, and resize the paper to the image size
5. Save the file as an SVG. This will be the outer edge of your custom PCB.

Begin by creating a new project in KiCad using the New Project button in the top left corner of the main window. After entering a name for the project, locate and open the file with the .kicad_sch extension to launch the schematic editor. This editor is where the basic circuit design is created and all electrical components are placed.

With the schematic editor open, components can be added to the design. In KiCad, these components are called symbols. Access the symbol library by navigating to Place → Place Symbol, which opens a searchable dialog. For this circuit, the required components include:

• Battery_Cell
• LED
• SW_SPDT (single-pole double-throw switch used as an on/off control)
• R (resistor)

After placing all symbols, use the Wire tool on the right toolbar to connect the components according to the circuit design. These wires define the electrical relationships between each part.

Pressing the R key rotates components!

Each symbol in the schematic must be assigned a footprint, which defines how the component will physically appear and connect on the PCB. The footprint tells KiCad the exact pad locations, hole sizes, and spacing required so the component can be properly manufactured and soldered onto the board. This ensures the physical component you use will match the PCB layout.

To assign a footprint, select a component and press F on your keyboard, or double-click the symbol to open the Symbol Properties dialog. From there, locate the Footprint field and click the library icon to open the footprint library. This library contains all available physical packages for components.

Once in the footprint library, enabling the following filters makes it easier to find compatible options:

• Apply footprint filters
• Filter by pin count

The library also includes a preview showing the pad layout, hole locations, and silkscreen markings, and many footprints include a 3D model to help visualize how the component will look on the final PCB.

For beginner designs, footprints labeled _THT (Through-Hole Technology) are recommended because they use larger holes and leads that are much easier to solder by hand. Footprints labeled _SMD (Surface-Mount Device) are smaller and designed for automated assembly or more advanced soldering techniques.

If the exact component you plan to use is not available in the default library, for example, a specific battery holder such as the DigiKey 3035, manufacturers and distributors often provide downloadable footprint files. These files can be imported into KiCad and used just like the built-in footprints, ensuring the PCB matches the exact physical component.

This process should be repeated for every component in the schematic to ensure the final PCB layout accurately reflects the real-world parts.

After assigning footprints to all components in the schematic, the next step is to open the PCB Editor, where the physical layout of the board is created. On the top right of the toolbar, there is a green icon that, when hovered over, says “Switch to PCB Editor”. Click this icon to open the PCB editor.

Once open, click the icon with a red arrow labeled “Update PCB from Schematic” to import all component footprints into the PCB layout. This ensures that the physical board matches the schematic design.

If you have a custom board outline, it can be imported as an SVG file by navigating to File → Import → Graphics

Make sure to import at a scale of 1 and onto the Edge.Cuts layer, which defines the physical boundary of your PCB. After the outline is imported, move your components into position within the Edge Cuts layer. Everything will start to take shape!

Once the components are positioned, the next step is routing the electrical connections, called tracks. Tracks function like wires, but are physically etched onto the board. Components can be rotated using the R key to optimize placement and reduce crossing tracks.

Tracks can be drawn on either side of the board:

• F.Cu (Front Copper) – routes on the front layer
• B.Cu (Back Copper) – routes on the back layer

For more complex layouts, it’s often helpful to split tracks between the front and back layers to avoid overlapping connections. Using through-hole components simplifies this process because connections can be made on either side of the PCB.

Some components may need to be flipped to the opposite side of the board depending on where their pads should be. In certain cases, you may also need to open the component’s properties to adjust the Net name (for example, + or -) so the routing path can be correctly etched.

Routing is complete when all connections are drawn and the Unrouted counter at the bottom of the screen reaches zero.

The same way you added the Edge Cut of your PCB, you can add ink to the front and/or back of your PCB. For us, we wanted a little mouth and nostrils, and we wanted to put the UF Makerspace Logo on the front. So we created an SVG in inkscape, and this time when we uploaded it to KiCAD, we chose the F. Silkscreen layer.

The generated Gerber zip file can be uploaded directly to JLCPCB to manufacture the board.

After logging in:

• Click Order Now
• Upload the generated .zip Gerber file
• Wait for the preview to load
• Open the Gerber Viewer to confirm the board appears correctly

For affordable shipping, select:

• Global Standard Direct Line – typically delivers in about two weeks

Most other settings can remain at their default values. Once the order is placed, the PCB will be fabricated and shipped. We were able to get our 5 pilot PCBs for $5.15, including shipping.