Mechanical keyboards have risen in popularity among a variety of users due to their customization capabilities and superior level of support. A key component of these mechanical keyboards is the Printed Circuit Board (PCB), responsible for registering keystrokes and sending signal to the computer. DIY builders who are interested in constructing their own mechanical keyboards will need to have a good understanding of PCBs.
Understanding Mechanical Keyboard PCBs
The PCB is the heart and soul of a mechanical keyboard, underlain every mechanical key. It consists of thin circuit lines, where an electrical signal flows. When a key is pressed, the switch closes the circuit on the PCB, allowing electricity to flow from one end to the other. This completes the circuit and sends a signal to the computer, triggering the corresponding character or function.
PCBs are created by placing layers of copper onto a substrate material like fiberglass, then using specific processes such as etching and drilling to create the desired circuit patterns. They come in numerous varieties to accommodate different keyboard sizes and layouts, from standard full-sized boards to minimal 60% designs.
Mechanical Keyboard PCB Features and Options
There are different types of PCBs that DIY builders can choose while crafting their custom mechanical keyboard.
Hot-Swappable PCBs: These PCBs allow for easy swapping of switches without the need to solder or de-solder anything. This gives you the freedom to experiment with different switch types without committing to one in particularly. However, they tend to be more expensive and less customizable than other types of PCBs.
Pre-soldered PCBs: These PCBs come pre-soldered with all necessary components like resistors, diodes, and LEDs, and they usually support most layouts. This is ideal for beginners who do not want to solder anything.
Barebones PCBs: These are bare PCBs that will require the user to solder all the components, including the switches. They offer the greatest degree of customization and flexibility for builders willing to get their hands dirty.
PCB Layouts and Modules
When considering PCBs, determining the layout is crucial. Mechanical Keyboard PCBs come in several sizes and patterns, with the most common layouts being Full size with Numpad, Tenkeyless (TKL), 75%, 65%, and 60%. Each layout offers unique user experiences and has advantages for different situations.
Full-sized PCBs feature all keys including the number pad, function keys, and multimedia keys. TKL PCBs lack the number pad for more desk space efficiency while retaining most of the functional keys. Smaller layouts like the 60% and 65% forego some functional keys to offer extreme compactness and portability.
Builders can also opt for a split PCB for an ergonomic keyboard or a macro pad PCB that has customizable keys for specific commands.
PCB Materials and Quality
Generally, PCBs for mechanical keyboards are made from FR4 (fire-resistant) fiberglass material, known for its durability and electrical insulation properties. Some high-end PCBs may utilize materials like polyimide or PTFE for better performance and longevity.
Thickness, copper weight, and finish quality are important characteristics of a quality PCB. A thicker PCB (1.6mm-2mm) with a higher copper weight (1oz-2oz) generally means a more durable and reliable board. The finish quality, often achieved via a process called Surface Finish, impacts corrosion resistance and electrical properties.
Firmware and Programming
The firmware of the PCB governs how the keyboard interprets keypresses and sends these inputs to the computer. Some common firmware in DIY PCBs include QMK (Quantum Mechanical Keyboard firmware) and TMK. Both are open-source and fully programmable, allowing builders to customize each key action.
Compatible Connectors
It is also essential to ensure your PCB is compatible with the right type of connector. The most common connector types are Mini USB, Micro USB, USB-C, and Bluetooth. USB-C is becoming the standard due to its reversibility and high data transfer rate.
Final Thoughts
Understanding PCBs is crucial for DIY builders looking to create a custom mechanical keyboard. It’s not merely about finding a profile you like, it’s about understanding the foundation and ‘brains’ of your keyboard. With the right knowledge, builders can navigate through different PCB types, layouts, materials, firmware options, and connectors to create a truly personalized typing experience. As you delve deeper into your DIY journey, these finer details will become second nature and the satisfaction of having a keyboard tailored to your needs will be worth the effort.
