HelloWord Smart Keyboard

This is a fully customizable, modular mechanical keyboard designed as both a functional input device and an extensible platform. The main appeal is that the left side can be swapped out with different components—the default one includes a small e-ink display, a motorized rotary knob with force feedback, and programmable RGB lighting, all working seamlessly with the keyboard.

The keyboard is built from the ground up with custom circuit boards and firmware. The creator designed ten separate PCBs that handle different functions: the main keyboard input, the swappable left module, connection points for attaching modules to a dock base, USB hub expansion, USB-C charging and connection, touchscreens, and encoder feedback for the motor. Everything is wired together through small ribbon cables. The keyboard scans its keys using a clever technique with shift registers—basic chips that let one data line control many buttons at once—which keeps the circuit simple and the scanning speed fast. All the keys have individual RGB LEDs that can display custom animations.

The firmware is written in C for STM32 microcontrollers (one chip for the keyboard, another for the left module). It handles key debouncing, HID protocol communication with a computer, RGB lighting effects, motor control with field-oriented control (a technique for smooth motor operation), e-ink display rendering, and more. The keyboard communicates with a computer as a standard USB device, so it works on Windows, Mac, or Linux without special drivers. The left module can run independently or communicate with the main keyboard over serial protocol, making it modular—you could theoretically build just the rotary knob part or just the keyboard part.

This project appeals to enthusiasts who want to build or customize their own keyboard hardware and understand every layer of how it works. It's especially useful for people who want to experiment with new input methods—like using a motorized knob with haptic feedback—without designing everything from scratch. The creator has released PCB design files, 3D printable case models, complete firmware source code, and documentation so others can modify or rebuild it. A PC application for changing the e-ink display image is included, and a key remapping tool and app store are planned but still in development.