Electronic Product Design Progress Report: Week 2

Schematic

This week, I decided to focus on drawing a schematic in KiCAD so that I can design a printed circuit board.

Annotation 2019-02-10 123607.jpg

Due to the amount of input required for the keyboard, two MCP23017 integrated circuits were added to acomodate up to 32 extra GPIO ports on the Feather board. The MCP2307 was chosen due to my preference of working with !2C devices.

PCB Design

After completing the schematic, the PCB was laid out and designed.

PCB Front Copper Layer

PCB Front Copper Layer

PCB Back Copper Layer

PCB Back Copper Layer

PCB Front Silk Screen Layer

PCB Front Silk Screen Layer

During the creation of the PCB, I decided to utilize some surface mount components in order to keep the size of the board as small as possible. Also, I had to reduce the number of notes as the number of buttons in the original design would not fit on the size of circuit board that I chose.

I purchased 12x12mm buttons with plungers (stems) for the keys as they supported key caps that would protrude through the final case.

The footprint for the surface-mounted on-off switch that I purchased were not included with KiCAD or could be found in the Digikey or Adafruit libraries. Therefore, I had to make a custom footprint in order to create the pads in order to solder the part to the board (SW15).

3D Render of the Front of the PCB

3D Render of the Front of the PCB

3D Render of the Back of the PCB

3D Render of the Back of the PCB

Ordering PCBs

After checking my design for any mistakes, I uploaded the KiCAD file to OSHPark and placed an order for 3 PCBs.

Order confirmation from OSHPark

Order confirmation from OSHPark

The schematic and PCB files can be found on the GitHub page for this project.