Doug Engelbart’s Chorded Keyboard as a Multi-touch Interface
Doug Engelbart’s contributions to computing and human-computer interaction have been phenomenal. In what’s been named “the mother of all demos,” Doug and his team introduced the world to the mouse, video conferencing, hypertext, multi-pointer collaborative interfaces, and dynamic file linking (all in 1968!). If you’ve never watched the videos of the demo, definitely check them all out.
However, what’s often left out was an equally-important input device opposite the mouse, the chorded keyboard. Using this input, the user could type and issue key commands using only one hand. This left the other hand free to navigate with the mouse. Unfortunately, since there’s a pretty steep learning curve to using a chorded keyboard, it never really caught on.
HOW IT WORKS
A chorded keyboard works by using combinations of finger presses to signal a keypress (for example, pressing both the first and second finger down simultaneously might send an “A”, while pressing the first and third finger down might send a “B”). With 5 fingers, there are 32 possible binary combinations. Leaving out the rest state (all off), and a drag state (all on), we have 30 useful mappings. With 26 letters, that even leaves a few for high level text commands (such as space, delete, and enter).
As designers, we all know that on-screen soft keyboards are cumbersome and rather slow to use due to their lack of physical texture and haptic feedback. And with the continual rise of touch screens on phones, tablets, and laptops, we got excited about giving the chorded keyboard another chance!
Here’s what makes this little keyboard so exciting:
- One handed use.
- Bring it up anywhere by putting down all 5 fingers.
- Large hit area per key (since there are only 5 keys to press) allows for blind/touch-typing operation.
- Contextual feedback to make learning easier (possible letters are shown at each level).
- Drag anywhere by pressing all 5 fingers down and moving your hand.
- Cancel a mid-phase chorded keypress by pressing all 5 fingers.
- Issuing keypress on touch-up allows users to type at any speed.
TRY IT OUT YOURSELF
Ok, enough build-up. :) If you have a tablet (android or iPad) handy,
give the chorded keyboard a try here!