The Terpstra Keyboard
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The Terpstra Keyboard

A keyboard from another planet. With 280 velocity sensitive, micro-tonal keys, the Terpstra keyboard offers musicians an incredibly expanded world of sound – a liberation from the confines of the 12 note octave.


An entirely different way of understanding music

Digital keyboards with a piano-key layout cannot be used to play musical scales with more than 12 notes per octave, as the kinaesthetic mapping does not make sense across the range of the keyboard keys. Siemen Terpstra devised an innovative key layout for playing musical scales with more than the "standard" 12-notes per octave; for example, 17 notes or 55 notes per octave.

Cortex was tasked with taking Siemen's conceptual design and producing a functional mechanical design to enable expressive musical performance.

The prototype 

We completed all circuit design, analysis and firmware development to simultaneously scan 280 keys at a rate fast enough to determine each key's position and velocity in real-time. Prior to the expense of creating a full-size prototype, we developed a seven-key subset of the full-size keyboard to evaluate key design and help with firmware development and testing.   


Our task became more complex when we realized that keyboards take a huge amount of abuse during live performance. During production prototyping, we developed a precision machine that’s also built like a tank; the Terpstra keyboard can withstand the constant pounding of an energetic concert performance. 


Innovating for improved usability

The beauty behind the Terpstra keyboard is that anyone, regardless of musical experience, can play it. Through the help of various tactile and visual clues, the user faces a dramatically smaller learning curve than with a traditional keyboard, which could take well over a decade to learn.

The geometry of the keyboard layout is characterized by a vertical shift in position between the top surface of a key and the six keys adjacent to it. This results in an intuitive feel for changes in pitch as your fingers move across the keyboard.


Truth; This Keyboard is a Little Weird