As an imbitious project I had decided to construct my own miniature single-handed keyboard from scratch with hand-wired/soldered parts, 3d printed keycaps and a pro-micro controller. The concept of this design was to have a keyboard and mouse setup in which you wouldn't have to remove your hand from the mouse, allowing for steady workflow in mouse-heavy programs such as 3D design software or CAD.
Design
A simple grid design was decided on, in which the vertical and horizontal keys are connected in a grid structure creating a unique set of "coded outputs" that correspond to each key. This saves a bunch of wiring when compared to direct wiring of each key to the microcontroller.
As this was my first ever keyboard build, so I took heavy inspiration from those already online, namely the Corne keyboard (crkbd). However, adjustments were required for hand-wiring (as apposed to using PCB) such as reshaping the casing to allow for more space, and relocating the casing screws.
3D Printing
Casing, keyplate and keycaps were all 3D printed to fit specifications and mx switches.
Programming
Programming was arguably the most difficult part of this process as I wanted to design a system of single-handed typing of which the keyboard could have a different keyset when states were toggled by the thumb keys. In theory, this would allow seamless typing while still allowing access to the mouse but intuitive design proved difficult. My final approach consisted of 3 states:
- Left side of standard keyboard letters
- Right side of standard keyboard letters
- Numbers and special characters
Relearning to type on this layout is difficult, however, given the time I believe this device could be of use within the design industry.
Soldering
Soldering the grid system and zener diodes was simple and by the end of this project I was far more comfortable with soldering.
Conclusion
In conclusion, the handwired keyboard build was a success and I believe I created a relatively unique device, as well as learned important skills of part choice, software/flashing and improved my soldering.