Story
TCBK40 – Open-Source 40% Mechanical Keyboard (DIY Kit)
Overview
The TCBK40 is a compact, high-performance 40% mechanical keyboard designed for enthusiasts, makers, and developers who want full control over their typing experience.
Originally developed as a mechatronics engineering project, the TCBK40 combines custom PCB design, QMK firmware integration, and modular hardware architecture into a powerful and accessible DIY keyboard platform.
This project is fully open-source and optimized for DIY assembly, customization, and small-batch manufacturing, making it ideal for both beginners and advanced builders.
Key Features
⚡ Compact 40% Layout
- Minimalist design with reduced footprint
- Full functionality through programmable layers
- Optimized for efficiency, speed, and desk space
The 40% layout eliminates unnecessary keys while maintaining usability via layer-based key mapping, allowing advanced workflows in a compact form factor.
???? Powered by QMK Firmware
- Fully programmable keys
- Multi-layer support
- Macro functionality
- Custom RGB control
The keyboard uses QMK (Quantum Mechanical Keyboard) firmware, enabling complete customization of layout, shortcuts, and lighting behavior.
???? Per-Key RGB Lighting (SK6812)
- Individually addressable LEDs
- Dynamic lighting effects
- Fully customizable through firmware
The TCBK40 uses SK6812 RGB LEDs, allowing precise control of color and brightness for each key, enhancing both aesthetics and usability.
???? ATmega32U4 (Pro Micro Compatible)
- Native USB HID support
- Easy programming via Arduino / QMK
- Widely available and beginner-friendly
The design is based on the ATmega32U4 microcontroller, commonly used in Pro Micro boards, ensuring accessibility and reliable performance for DIY builders.
⚙️ Custom PCB with Anti-Ghosting
- Matrix-based key scanning
- 1N4148 diodes for each key
- Reliable multi-key input (N-key rollover ready)
Each key is protected with diodes to prevent ghosting, ensuring accurate input even during fast typing or gaming.
???? Modular & DIY-Friendly Design
- Compatible with MX-style switches
- Replaceable components
- Designed for easy assembly and modification
The PCB and structure are optimized for manual assembly, making it perfect for learning electronics and keyboard building.
???? Acrylic Case with Open Design
- Transparent acrylic switch plate
- Exposed components for a unique aesthetic
- Lightweight and durable
The open design highlights the PCB and components, creating a tech-focused, industrial look while maintaining structural stability.
????️ 3D Printable Back Case
- Customizable rear enclosure
- Easy to modify and personalize
- Reduces production cost
The back case can be manufactured using 3D printing, allowing users to create their own designs and styles.
Technical Specifications
- Layout: 40% Mechanical Keyboard
- Firmware: QMK (Open Source)
- Microcontroller: ATmega32U4 (Pro Micro compatible)
- Switch Support: MX-style mechanical switches
- Lighting: SK6812 RGB LEDs (per-key addressable)
- PCB: Custom-designed (KiCad)
- Matrix: Diode-protected (Anti-ghosting)
- Connection: USB (via Pro Micro)
- Case: Acrylic plate + optional 3D printed back
What This Product Includes
DIY Kit Version:
- PCB (TCBK40)
- Acrylic switch plate
- Required electronic components
- Assembly documentation
Files Version (Open Source):
- PCB (Gerber files)
- Schematics
- Firmware (QMK configuration)
- Case design files (3D + plate)
Who Is This For?
- Mechanical keyboard enthusiasts
- DIY builders and makers
- Electronics students and engineers
- Programmers and productivity users
- Anyone interested in custom hardware
Why TCBK40?
The TCBK40 is more than a keyboard — it is a learning platform and customizable tool.
It demonstrates how modern tools like KiCad, Fusion 360, and QMK can be combined to create a fully functional product from scratch, while remaining accessible and affordable.
This project proves that high-quality, customizable hardware can be designed, built, and shared by independent creators.
Open Source & Community
All design files are available for modification and improvement.
You are free to:
- Build your own version
- Modify the design
- Create derivatives
- Learn from the project
Final Note
The TCBK40 was developed with a strong focus on:
- Performance
- Simplicity
- Customization
- Accessibility
Whether you're building your first keyboard or refining your workflow, this project gives you full control over your hardware.
