Mechanical Keyboard PCB: DIY Custom Keyboard Tutorial

After customizing the circuit layout, the next step is to create the traces that connect all the components. These traces are the conductive paths on the circuit board that allow current to flow between different components, so the design should provide smooth current flow without any interference or noise.

To achieve this, it is recommended to follow these guidelines:

• Shortest path principle: When laying out traces, ensure that these lines are the shortest possible, and check if there is a shorter route available. This helps to improve signal transmission speed and reduce signal distortion.
• Avoid cross-interference: Line crossing can cause interference problems on the board, especially between digital and analog signals. To prevent this, keep the traces as far apart as possible, or use a ground plane to separate them.
• Wider traces: Using wider traces with larger cross-sections in keyboard circuits reduces resistance, allowing circuits to handle more current flow and reducing the risk of overheating. A good rule of thumb is to use a trace width at least equal to the drill size of the via being used.
• Signal direction: Ensure that the output direction of the signal is consistent during the design process to avoid any potential signal flow issues.

Mechanical keyboard casings can be manufactured from a variety of materials and sizes, including plastic, metal, acrylic, and wood, and are available in various styles and colors.

• Plastic casings: Are produced using an injection molding process, where molten plastic is injected into a mold and then cooled and hardened to form the final keyboard case. The shape of the mold determines the final shape of the keyboard.
• Metal casings: Can be created through stamping or milling processes, where a metal sheet is formed into the required shape and size. Machine tools are then used to weld or glue the individual parts together, creating a complete keyboard enclosure.

• Keycap Profile: Refers to the shape and contour of the keycap, It can vary in height, curvature, and angle. The most common profiles include OEM, Cherry, SA, and DSA. Each profile has its own unique feel and aesthetic appeal, and it is important to choose the right profile for your custom keyboard based on your personal preference and typing style.
• Keycap Color: It can significantly enhance the appearance and visual appeal of your custom keyboard. You can choose a single color for a minimalist look, or mix and match colors to create a more unique and eye-catching design. It is important to consider the color scheme of your keyboard PCB and the surrounding environment to ensure that the keycaps blend in harmoniously.
• Keycap Legends: Refer to the labels or symbols that are printed or engraved on the keycaps. You can choose to have legends that match the standard layout, or customize them to suit your specific needs, such as including additional function keys or symbols. The keycap legends should be clear and easy to read, and they should not wear off easily with prolonged use.

To incorporate LED functionality into a keyboard, two methods can be utilized, namely surface mount and through hole, both of which are applied to the PCB board.

• Surface mount: Involves soldering the LED directly onto the circuit board’s surface via SMT assembly, typically utilized for RGB backlight effects. This method requires wiring to connect the LEDs to the microcontroller or firmware for programming to produce different lighting patterns. While wiring, it is essential to ensure proper polarity and resistance matching to prevent overcurrent damage to the LED.
• Through-hole:  Is accomplished by inserting the LED into a metal socket with pre-drilled holes, requiring holes to be drilled in the PCB to fit the metal socket. This method is usually used to realize single-color LEDs and backlight strips.