Handwiring Mechanical Keyboards: Your Ultimate Wire Guide

Handwiring a mechanical keyboard might seem daunting, but it’s a rewarding process that allows for complete customization. While guides existed before, many early methods weren’t as efficient or robust. This comprehensive Wire Guide refines the handwiring process, offering techniques for a stronger, cleaner, and easier build. Whether you’re a seasoned DIY enthusiast or a newcomer to the world of custom keyboards, this guide will walk you through each step to create your own unique mechanical keyboard.

1. Preparing Your Plate: The Foundation

The keyboard plate is the base upon which your entire handwired build rests. Before proceeding, meticulous inspection is crucial. Any imperfections overlooked at this stage can cause issues later in the build.

Inspecting for Imperfections: Carefully examine the plate for any warping, misalignment of switch holes, excess material, or any irregularities. These flaws can hinder switch installation and overall keyboard functionality.
Material and Thickness Considerations: The material and thickness of your plate will influence switch stability. A 1.5mm steel plate, like the one used here from Lasergist, generally provides a snug fit, securing switches firmly without glue.

2. Switch Installation: Ensuring a Secure Fit

With your plate prepared, the next step is installing the mechanical keyboard switches. The fit should be secure, especially with a 1.5mm plate.

Mounting the Switches: Press each switch firmly into its designated slot on the plate. A properly cut plate should allow the switches to snap in place, requiring a bit of force to remove. If the switches are loose, consider using a plate of different thickness or explore switch films for a tighter fit.
Testing Switch Functionality: As you install each switch, press it a few times to ensure smooth actuation and responsiveness. While rare, switch defects can occur. For thoroughness, especially if you have time, use a multimeter to test each switch’s actuation for electrical continuity, guaranteeing each key will function perfectly.

3. Diodes: The Key to Matrix Magic

Diodes are essential components in a handwired keyboard matrix. They prevent ghosting and key rollover issues, ensuring each keypress is correctly registered even when multiple keys are pressed simultaneously.

Why Diodes are Essential: Diodes create a matrix circuit, allowing the controller to identify individual key presses within rows and columns. Without them, pressing multiple keys could lead to incorrect signals.
The Loop Technique for Diode Attachment: For a robust and reliable solder joint, the diode wire should form a loop around the switch pin. This mechanical connection, even before soldering, enhances joint strength. This looping method will be consistently used for all solder connections in this wire guide.
Bending and Preparing Diodes: Using 1N4148 diodes, start by pre-bending a batch. Wrap the diode wire around needle-nose pliers to create a small loop close to the diode body. Pinch the loop closed with pliers for a tighter, circular shape, and clip excess wire. This tight loop ensures good electrical contact and cleaner soldering.

4. Soldering 101: Mastering the Joints

Soldering is the process of creating permanent electrical connections. Understanding solder’s properties and applying proper techniques are key to clean and functional joints in your handwired keyboard.

The Surface Tension Advantage: Solder’s surface tension is your friend in creating clean joints. The loop technique maximizes this. Position the loop at the base of the switch pin, utilizing the diode wire’s excess length for stability.
Achieving Clean and Effective Solder Joints: Apply heat from your soldering iron to the pin and loop for a few seconds. Then, touch the solder to the iron’s tip, allowing it to flow into the loop and encase the connection. Use just enough solder to fill the loop’s interior, creating a secure joint without excess. Remove the iron and solder promptly once the joint is formed.

5. Vise Grip Magic: Wire Stripping Made Easy

Preparing wires with insulation gaps for rows and columns can be tedious. A vise grip tool offers a game-changing method for creating these gaps efficiently and cleanly.

Why Vise Grips are a Game Changer: A vise grip tool allows you to create insulation gaps in the middle of a wire run without cutting individual segments. This method is faster, cleaner, and more consistent than using razor blades or traditional wire strippers.
Step-by-step Vise Grip Technique: Measure and mark the desired insulation gap lengths on your wire. Align the wire with landmarks on the vise grip tool (like the screw protector) for consistent spacing. Clamp down firmly to compress the insulation. Since the insulation is compressed, not removed, trim the excess insulation along the wire edges to create the desired gaps.
Solid Core vs. Stranded Wire: Solid core wire is highly recommended for vise grip stripping and handwiring in general. Stranded wire is significantly more challenging to work with using this method due to its flexibility and tendency to fray.

6. Row Wiring: Connecting the Horizontal Lines

Row wires connect diodes horizontally across the keyboard matrix. Solid core wire is ideal for rows, and slightly thicker insulation provides added safety.

The Row Wiring Technique: After vise-stripping insulation gaps along a length of solid core wire to match your keyboard layout, position the wire over the row of diode wires.
Looping Diode Wires for Secure Connections: Instead of bending all diode wires over the row wire at once, bend only one diode wire at the edge over the row wire to temporarily secure it. Remember not to trim the outer edge of the diode wire until after soldering. Then, feed the diode wire back under the row wire, forming a loop around it.
Maintaining Row Wire Snugness: Solder this initial joint. Push the insulation against the joint, then loop the next diode wire around the row wire. Push the remaining insulation pieces aside as you proceed down the row, soldering each joint sequentially. This method allows for direct solder joints between the diode wire loops and the row wire without damaging insulation and keeps the row wire snug against the switch column for a cleaner and more robust build.

7. Column Wiring: Completing the Matrix

Column wiring mirrors row wiring, connecting switch pins vertically. The same vise grip and looping techniques apply.

Column Wiring Techniques: Vise-strip a wire with insulation gaps to the correct lengths. Create loops on the column wire, similar to the diode wire loops, to wrap around the switch pins.
Looping and Soldering Column Wires: Work one loop at a time, soldering each immediately after forming the loop. Place the column wire next to the switch pin, pull it tight to form the loop, remove and pinch the loop with pliers, reposition it around the pin, and solder close to the pin’s base. Ensure each wire section has enough slack to prevent stress on the row wires.
Wire Choices for Columns: Solid core wire is ideal for columns, and you can use wire with thinner insulation. Individual strands from networking cables like Ethernet or telecom cables are excellent choices due to their thin insulation and vibrant colors, as used in this example with strands from a scrap telecom cable.

8. Controller Wiring: Connecting the Brain

The controller acts as the brain of your handwired keyboard, interpreting key presses. Ribbon cable simplifies controller wiring for a cleaner setup.

Using Ribbon Cable for Clean Controller Connections: While normal wire works, ribbon cable provides a cleaner and more organized way to connect the keyboard matrix to the controller. A ribbon cable, like the pictured example (possibly this one), makes connecting to the controller pins straightforward, especially if using compatible connectors.
Pin Considerations (D6, GND, VCC Avoidance): When wiring a Teensy controller, it’s important to avoid using pins D6, GND, and VCC, as they can sometimes cause issues. Use other available GPIO pins for your rows and columns.
Controller Placement Tips: Controller placement depends on your case design. In this build, the controller is placed in a specific location due to ribbon cable length. Consider ribbon cable length and case constraints when deciding on controller placement.

9. Clean Up and Testing: Ensuring Reliability

Once wiring is complete, thorough testing and cleanup are crucial to ensure a functional and durable keyboard.

Multimeter Testing for Continuity and Shorts: Use a multimeter to test for continuity between each row start and every diode wire in that row, and similarly for columns and switch connections. Verify that no row is connected to any column (no shorts). Also, check that each controller pin connects to the correct row/column joint, and not adjacent joints. A multimeter’s continuity test (beep mode) is invaluable for this process.
Trimming Switch Pins for a Clean Finish: Use thin wire cutters to carefully trim the excess switch pins. If your soldering is neat and loops are pressed down well, you can trim pins quite close to the solder joints, ensuring they don’t interfere with the case or other components.
Inspecting Solder Joints: Visually inspect every solder joint. Ensure solder fully surrounds each loop, creating a complete and robust electrical and mechanical connection.

10. Finishing Touches: Case and Firmware

The final steps involve choosing a case and configuring the keyboard firmware.

Choosing a Case: Showcasing Your Work: Select a case that complements your handwired creation. Options range from layered acrylic cases to simple sandwich standoffs, or even running the keyboard without a case to showcase the handwiring artistry.
Firmware and Final Steps: Programming the firmware is the last critical step. QMK Firmware (http://qmk.sized.io/) is a popular and powerful choice for custom mechanical keyboards. A multimeter can be helpful in verifying pin assignments if you used a ribbon cable. Congratulations, you’ve successfully handwired your own mechanical keyboard!