"A macropad is the only keyboard that does exactly what you tell it to do with zero compromise.
"KaiRenner26th of April 2026
What a Macropad Is
A macropad is a small custom keyboard — typically 4 to 16 keys — programmed to send macros, keyboard shortcuts, or system commands. It runs QMK or KMK firmware that maps each switch to any keycode or action you define. Popular builds use a Pro Micro or RP2040 microcontroller, a handwired switch matrix, and open-source firmware. A 3x4 macropad takes an afternoon to build and no PCB design experience.
3x 4 Keys
1N4148
Design the Layout and Source Switches
Pick your key count, choose switches, and order per-key diodes.
Design the Layout and Source Switches
Choose your layout — 3x3, 4x4, or any grid arrangement. Source MX-compatible mechanical switches (Cherry MX Red, Gateron Yellow, Kailh Box switches are popular choices). Order 1N4148 signal diodes (one per switch), an RP2040-based controller (KB2040 or similar), a USB cable, and keycaps. A top plate of acrylic or aluminum gives the build rigidity.
Solder the Switch Matrix
Solder switches in rows and columns with diodes on each switch.
Solder the Switch Matrix
Arrange switches in your grid. Bend a diode leg around each switch pin and solder. Link diodes in rows: connect all diode cathodes (black band end) in a row with a piece of wire or by bending the legs to touch. Connect all switches in each column by soldering column wires to the remaining switch pins. You now have a row/column matrix.
Wire to the Controller
Connect each row wire and column wire to a GPIO pin on the controller.
Wire to the Controller
Connect each row wire to a GPIO pin on the microcontroller and each column wire to another GPIO pin. Note which GPIO corresponds to which row and column. For a 3x4 pad: 3 row pins and 4 column pins = 7 total GPIO pins needed. The controller scans the matrix to detect which keys are pressed by setting rows HIGH and reading columns.
Flash QMK Firmware
Configure your matrix in QMK and flash the firmware via USB.
Flash QMK Firmware
Clone the QMK firmware repository. Create a new keyboard directory with your matrix configuration (row/column pin assignments) and keymap. Define your keymap layer with keycodes for each position — standard keycodes, macros (SEND_STRING), or layer toggles. Build with `qmk compile` and flash with `qmk flash`. QMK Configurator offers a graphical interface for keymap creation without code.
Parts List for a 3x4 Macropad
12 mechanical switches (MX-compatible)
12 diodes — 1N4148
KB2040 or Pro Micro RP2040 controller
12 keycaps
USB-C cable
Acrylic or aluminum switch plate (laser cut or DIY)
Soldering iron and solder
Wire (28 AWG)
QMK Setup on Windows Requires WSL or MSYS2 QMK compilation on Windows works best through WSL2 (Windows Subsystem for Linux) or the QMK MSYS environment. Follow the QMK documentation for your OS exactly — environment setup errors are the most common beginner problem. Once compiled once, subsequent builds are straightforward.
"Twelve keys. Each one does exactly one thing. That is the entire design philosophy.
"KaiRenner26th of April 2026
