Smallest keyboard layout

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Learn about the smallest keyboard layout, a 40% keyboard with 40 switches, and how to build one using a microcontroller like STM32F103.

intermediate Published 6 Apr 2026
Action Steps
  1. Research the 40% keyboard layout and its components.
  2. Choose a microcontroller with HID capabilities, such as the STM32F103.
  3. Hand-wire the keyboard switches to the microcontroller.
  4. Program the microcontroller to recognize keyboard inputs.
  5. Test and refine the custom keyboard layout.
Who Needs to Know This

Hardware enthusiasts and DIY keyboard makers can benefit from this article, as it provides insight into building a custom keyboard layout.

Key Insight

💡 A 40% keyboard layout can be built using a microcontroller with HID capabilities, such as the STM32F103, and hand-wiring keyboard switches.

Share This
🖥️ Build your own 40% keyboard with just 40 switches! 🤯 Learn how to use a microcontroller like STM32F103 to create a custom keyboard layout. #DIY #keyboard #hardware

Key Takeaways

Learn about the smallest keyboard layout, a 40% keyboard with 40 switches, and how to build one using a microcontroller like STM32F103.

Full Article

Title: Smallest keyboard layout

URL Source: https://dev.to/fallingdowncat/smallest-keyboard-layout-3m77

Published Time: 2026-04-08T16:06:07Z

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Posted on Apr 8 • Originally published at [fallingdowncat.com](https://www.fallingdowncat.com/smallest-keyboard-layout/) on Apr 6

# Smallest keyboard layout

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Smallest keyboard layout possible is called 40% keyboard. It has about 40 switches, and those are all letters and couple of necessary keys for writing, like space, enter, backspace... In order to make something like that keyboard, a microcontroller with HID capabilities is required. In my case i used STM32F103 aka Bluepill.

It's possible to just buy one of those development board really cheap from China, and hand wire all the
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