Beginning with an understanding of what mechanical keyboard hand wiring entails, it is basically a method of constructing a keyboard without the use of a printed circuit board (PCB). Instead, the keyboard enthusiasts wire each key to a companion microcontroller which receives the input and communicates it to the computer.
The first phase of getting crafty with mechanical keyboard hand wiring is gathering the necessary components. As with any craft project, you’ll need to ensure you are properly equipped before starting. Knowing the necessary components is key to understanding the process. The essentials for this project include a microcontroller, switches (one for each key), a mounting plate, diodes (one for each key), wires, a soldering iron, solder, wire strippers, and needle-nose pliers. It’s also advisable to have a layout in mind or even a custom-designed one, depending on your preference.
The microcontroller you use is of great importance. It’s the brain of the keyboard that sends each key’s input to the computer. A popular choice amongst mechanical keyboard enthusiasts is the Teensy 2.0 from PJRC. It has 25 I/O pins, uses standard micro-USB and is fully programmable, making it perfect for custom keyboard builds.
The mounting plate is also critically important since it serves as the chassis for your keyboard. It anchors down the switches and provides the overall structure. There’s a choice between plastic or metal mounting plates. Metal plates are sturdier, while plastic ones are cheaper but less durable.
Mechanical keyboard switches are the keys you’ll be pressing on the keyboard. Choose switches that suit your feel and sound preference. They are typically categorized into linear, tactile, and clicky. Linear switches are smooth and restful, tactile ones have a popcorn-like bump in the middle, while clicky ones give a clear audible sound when pressed.
Diodes play an essential role in hand wiring your mechanical keyboard. They prevent something known as “Ghosting,” where the keyboard erroneously detects a keypress. Each key will need to have a diode, so count the number of keys your layout will have.
Planning the hand wiring is the next crucial step. The matrix is the configuration in which these switches are wired to the controller. A regular keyboard has a grid of X and Y coordinates, where every key on a row shares X, and every key in a column shares Y. When a key is pressed, the controller knows which key it is by the intersection of the X and Y.
Create a spreadsheet of your layout and number each row and column. Do note that due to the limitation of the number of input/output ports on a microcontroller, rows and columns might need to be combined. As a general rule though, the number of rows/columns should not exceed that of the available pins on your controller.
Soldering is the next phase. Start by placing your switches into the mounting plate. Be mindful of orientation, as trying to rectify a mistake in this step will be bothersome. Insert the diodes into each switch, making sure they are directed in the correct orientation. Your diodes should have a black line on one end, this line indicates the direction of current flow, and it should be pointing away from the switch.
Next, connect the rows by adding a wire that span the switches, soldering where the wire intersects the unlined ends of the diode. Now it is time to build the columns. Do not cross the rows; instead, have the wire zigzag, touching the other end of each switch in that column. For each row and column, one end will be left free. This free end will be soldered to the microcontroller. Be sure to disjoin each row and column wire from touching each other before connecting to the controller.
Programming the controller is the final yet essential stage. Tools like TMK or QMK can be used and are highly adaptable for most needs. Firmware creation involves defining your matrix in code and assigning each key. Using the layout made earlier, you create a keymap where each key location correlates with the key you want the keyboard to send.
The process can be daunting, but it’s an excellent project for anyone who loves to tinker with electronics or for those who want a highly personalized keyboard. With careful planning, correct tools, a pinch of patience, and a heap of creativity, anyone can craft a keyboard that is uniquely tailored to their needs. Whether it’s for more comfortable writing, gaming supremacy, or simply the satisfaction of having a customized piece of equipment, hand wiring your mechanical keyboard opens a world of opportunities to get crafty and innovative.
