Designed by Siemen Terpstra in the late 1980s, based on Erv Wilson's microtonal keyboard designs (1967-), inspired by R.H.M. Bosanquet's Generalised Keyboard (1873) and Ivo Salzinger's Tastatura Nova Perfecta (1721).
Initial development by James Fenn with additions and modifications from Brandon Lewis, Bo Constantinsen, Chengu Wang, Ashton Snelgrove. Sampling credits to Scott Thompson, Tim Kahn, Carlos Vaquero, Dr. Ozan Yarman, Lars Palo, Soni Musicae.
MIDI version designed and programmed by Marc Sabat. Current version 3.0.0 (2026), released as Free/Libre and Open Source Software under GPL-3.0. Code on github: https://github.com/PLAINSOUND/hexatone.
The Music Notation Project Wiki
Version 1 : 2016- [Terpstra Keyboard] (http://terpstrakeyboard.com/) hexagonal keyboard proof of concept
Version 2 : 2022-26 Marc Sabat: Added MIDI input and output, developed Lumatone plug-and-play compatability and built-in presets, MTS output
Version 3.0.0 : 2026- Added scala/json IO, user presets, polyphonic aftertouch response with built-in sounds