An Intro to KiCad – Part 1: How PCBs Are Made | DigiKey

Getting Started with KiCad: Creating a Custom PCB

Introduction to the Project

• Shawn Hymel introduces the video series focused on creating a custom PCB, specifically a badge that features pulsing LEDs and space for customization using a Sharpie.

• The badge can be personalized and worn at events, with the option to erase Sharpie marks using rubbing alcohol. Collaboration with DigiKey is mentioned for sourcing components.

Historical Context of PCBs

• Discussion begins on the evolution of PCB technology, starting from wire wrapping techniques used in telephone crossbar switches during the 1960s.

• Wire wrapping was an art form that created visually appealing patterns but was costly and time-consuming despite being automatable.

Transition to Surface Mount Technology

• The rise of surface mount technology (SMT) in the 1980s led to faster and cheaper electronics production compared to traditional through-hole technology.

• Explanation of plated-through holes (PTH), which enhance connections by adding conductive material inside drilled holes.

Understanding Printed Circuit Boards (PCBs)

• Definition of PCBs as boards that electrically connect and mechanically support electronic components via conductive tracks or traces made typically from copper.

• Description of PCB layers, including substrate materials like fiberglass and epoxy resin, emphasizing flame resistance standards (FR4).

Layers and Manufacturing Processes

• Overview of single-layer vs. multi-layer boards; two-layer boards will be used for this project due to their balance between complexity and cost.

• Process details on creating plated-through holes through drilling and electroplating, allowing electrical connections between different copper layers.

Finalizing PCB Design Features

• Explanation of etching processes that remove excess copper while retaining designed traces and pads for functionality.

• Importance of applying a solder mask layer for protection against short circuits; traditionally green but purple in this case due to OSH Park's specifications.

Additional Protective Measures

• Discussion on Solder Mask Keepout areas where soldering is desired; these are critical for ensuring proper connectivity without oxidation issues affecting soldering quality.

• Mention of surface finishes like electroless nickel immersion gold (ENIG), which enhances solderability and protects underlying copper traces.

Silkscreen Layer Utilization

Understanding PCB Design and KiCad

Overview of PCB Structure

• The bare substrate of a PCB is typically brown or tan, with exposed copper finished in gold, green solder mask, and white silkscreen.

• A Raspberry Pi PCB features six layers of copper, indicating a complex design compared to simpler boards.

Designing PCBs with CAD Software

• Most modern PCBs are designed using computer-aided design (CAD) software; each program has unique functionalities but follows a similar workflow.

• The initial step involves designing the circuit, which can be based on online resources or simulations. Circuit design is not covered in this series.

Creating Schematics and Footprints

• Custom schematic symbols may need to be created if they are unavailable in KiCad or DigiKey libraries before drawing the circuit in eeschema.

• The term "footprint" refers to the configuration of pads and holes for component attachment on the PCB; creating custom footprints may be necessary.

Generating Net Lists and Board Layout

• In eeschema, a net list is generated to document electrical connections between pins in the circuit.

• After importing the net list into pcbnew, parts are arranged, and copper traces are drawn to connect necessary pins.

Finalizing Designs and Ordering Components

• Gerber files representing various board layers are generated for manufacturer review; these can be examined using gerbview.

• A Bill of Materials (BOM) is created for ordering components from DigiKey after all parts arrive for assembly.

Learning Resources for KiCad Users

• Chris Gammell's tutorials titled "Getting to Blinky 4.0" provide additional insights into using KiCad effectively.

• The KiCad forums at forum.kicad.info offer community support for troubleshooting and learning more about PCB design.

Getting Started with KiCad Installation

• To begin designing PCBs, download KiCad from kicad-pcb.org according to your operating system specifications.