Type Quickly in Comfort with This DIY Chorded Keyboard

The simplest way to construct a keyboard is to devote a key to every possible character. But that would require 63 keys just for lowercase letters, capital letters, numbers, and spaces — before including punctuation, special characters, or necessary function keys like backspace. So we use modifier keys, like shift or control, to switch to alternate layers, reducing the number of keys. We can take that approach far further if we want to, which is the idea behind chorded keyboards. If you're interested in trying a chorded keyboard for yourself, Chordie is an awesome open source option that you can build right now.

Chorded keyboards work a bit like the T9 typing that we all used to text before smartphones came along. But instead of tapping a key multiple times to switch between characters, you press key combos — similar to piano chords. Chordie uses the ASETNIOP method, which works with ten keys. You can enter those letters, which are the most common on a QWERTY keyboard, by tapping a single key. Other letters, punctuation, and so on require chords. For example, pressing A and S together produces a W. You can also type entire words using special chords.

Learning the chords well enough to type at a respectable speed isn't easy, but building this keyboard is. It's based on an Arduino Pro Micro 5V development board, two MCP23017 expanders, and Kailh Choc mechanical key switches. The key switches are plate-mounted, so you don't need a custom PCB. After you 3D print the frame pieces using the provided STL files, you can pop the key switches right in. Then you can solder the wires from the switches to the IO expanders, which connect to the Arduino. There is even an optional trackball mouse, so you have everything you need in a small package.

Chorded keyboards are only for the brave, but with enough practice you can adapt to Chordie and type in ergonomic comfort.