Pitfalls
microtonal scale explorer / chord arpeggiator / isomorphic grid keyboard
item: There are pitfalls in using equal division within which
to calculate 2-interval-patterns which the unwary traveler
will most certainly fall into.
- Erv Wilson [0]

Many thanks to inspiration from Stephen Weigel, Sevish, Erv Wilson, and other explorers of microtonal/xenharmonic scales.
I’ve encoded my naïve interpretations into Pitfalls - a norns library for exploring microtonal scales and chords, and playing them via Grid as an isomorphic grid keyboard.
If there’s interest I can hone Pitfalls into a library for reuse - anywhere microtonal scale pitches are desired.
Already there are some concepts forming:
scale = Scale:new(2, 1, "LLsLLLs")
scale:set_mode(2)
intervals = ScaleIntervals:new(scale)
pitches = Pitches:new(scale, intervals, tuning = 432, midi_start = 60)
Requirements
- norns
- optional:
- grid (64 or 128 varibright)
- or midigrid (see edit settings to change grid lib)
Documentation
Explore & play your own microtonal scales.
Set interval structure as a sequence of large L, small s, and optional medium M steps.
For example, C Major diatonic scale:
LLsLLLs L: 2 s: 1 base: C
A 19 EDO, 7 note scale:
LLsLLLs L: 3 s: 2
Toggle note/chord arpeggiator to hear scales.
Pitfalls let’s you play your scales via grid as a isomorphic keyboard.
Controls:
-- E1 change cutoff filter
-- E2 change value
-- E3 select step or parameter to change
-- K1
-- K2 toggle arpeggiator
-- K3 toggle circle, original, and strings display modes.
Download
Available on maiden, or:
pitfalls v0.3.0 - in progress, may add monophonic pitch-bend live retuning to play microtonal scale pitches on external synths via MIDI.
pitfalls v0.2.0 giojoso geola - add circle/string display modes, medium M scale step, and show existing scale name if any.
pitfalls v0.1.0 einfach einem - just one octave, many scale pitfalls.
Source
References
[0] An Introduction to the Moments of Symmetry