Lumatone mapping for porcupine
There are several ways to map porcupine temperament onto the Lumatone keyboard. This article uses the Porcupine[7] notation convention from Porcupine Notation.
The mappings pictured below are based on mapping consecutive porcupine generator steps (~160 cents) to adjacent keys going generally left-to-right across the keyboard.
A completely different approach to playing porcupine music on the Lumatone would be to use a standard mapping for some porcupine EDO (e.g. the Lumatone mapping for 22edo) and learn the shapes of porcupine scales in that layout. For example in 22edo, porcupine steps go roughly vertically rather than roughly horizontally, thus requiring a lot of "wrapping around". But if you just learn the shape of a "porcupine tetrachord" that could be a fruitful approach.
Ultra-compressed
This has the largest range of any mapping shown here (5 complete octaves), but the sequence of nearby pitches can be confusing. In particular, notes separated by the Porcupine[7] chroma (denoted by ^/v here) are not mapped to adjacent keys.
Compressed
This is a compromise intermediate between the "ultra-compressed" and "expanded" mappings. It covers 4 complete octaves, and the Porcupine[7] chroma is now mapped to adjacent keys in the "vertical" direction. The sequence of pitches is still not completely intuitive, however: the Porcupine[15] chromatic scale still zigzags back and forth leaping over keys, rather than proceeding in mostly the same direction. This is because the Porcupine[8] chroma (denoted #/b on Porcupine Notation - for example the notes A and Bv are separated by this chroma) is still not mapped to adjacent keys.
Expanded
This mapping has the smallest range of any presented here - less than 4 complete octaves - but its main advantage is mapping the Porcupine[15] scale to an intuitive zigzag pattern. In-between pitches always appear in-between on the keyboard, rather than off to the side.