Recreating Engelbart’s Chorded Keyset ​

In 1968, Douglas Engelbart demonstrated a revolutionary computer system that included, among other innovations, a chorded keyset —a five-key device that allowed one-handed text input through combinations of keypresses^[1]. The keyset is an input method that never gained widespread adoption, and remain commercially unavailable.

Fascinated by this historical interface, I embarked on a journey to recreate and experience Engelbart’s chorded keyset firsthand. The project evolved through multiple prototypes, each iteration bringing me closer to understanding the unique affordances of this input method.

My first attempt used basic electronic components on a protoboard, using simple push buttons wired into an Arduino pro micro:

The next iterations improved the buttons, by using ice cream sticks and microswitches. It also included LED light indicators for different modes:

Then I built a simple enclosure and painted it:

The final design ​

While researching about the keyset, I learned that the XEROX Alto computer —developed years after Engelbart’s demo— also had a keyset^[2]:

So, I based my designs on that one. For the next prototype, I took the measurements of that version of the keyset and made a 3D model in FreeCAD:

Then, I printed it (using a 3D printer), and assembled it:

Closing Thoughts ​

The code and circuit diagram can be found on GitHub. I developed it using C++ and Ruby, with automated tests for the character entry logic.

I’ve found that recreating historical interfaces can give us the ability to experience them in a way documentation or videos can’t convey. While the chorded keyset may not have become the standard input device Engelbart envisioned, experiencing it firsthand provides valuable insights into alternative interaction patterns, and makes us think about the complex factors that influence technology adoption.