Midi Output
The Continuum Fingerboard assigns each finger on the playing surface its own Midi channel. It tracks up to 10 fingers (if the polyphony is set to 10), and transmits on Midi channels 1-9 and channel 12. The exact pitch of each finger is encoded as the nearest Midi note number to the initial position of the finger, plus the Pitch Bend on the finger's Midi channel. Note numbers range from 15 to 109 on a full-size Continuum Fingerboard, and from 40 to 85 on a half-size Continuum Fingerboard. The default Pitch Bend range is two octaves, and is user adjustable from 2 to 96 half-steps. The pressure of the finger is encoded (by default) using Channel Volume (controller 7), and the front-to-back position is encoded (by default) using Brightness (controller 74).
Details of Midi Encoding
When a finger first touches the playing surface, the Continuum Fingerboard selects the least recently used Midi channel, and transmits a Note On:
9n rr ii Note On (hex), rr is note nearest to finger position, ii=7F or ii=velocity (configurable)
When a finger is lifted from the playing surface it transmits a Note Off:
8n rr 00 Note Off, rr and n are same value as in Note On
The following three Midi messages are used to track finger movements. These three messages are always transmitted in the same order. They are transmitted continually between Note On and Note Off, and once immediately before the Note On and immediately after the Note Off:
Bn mm kk Front-to-back position, kk=00..7F; controller number mm is configurable
Bn 07 vv Finger pressure, vv=00..7F; other options for encoding finger pressure are available
En pp pp Pitch Bend, pppp=0000..3FFF; bend range is configurable
Every 200 ms, an Active Sensing byte is transmitted:
FE Active Sensing
The polyphony determines which Midi channels are used for output. For polyphony= 1, Midi channel 1 (n= 0) is used for output. For polyphony 2, Midi channels 1 and 2 (n=0 and n=1) are used. As polyphony increases, the number of Midi channels used for output increases. With increasing polyphony, the channels are used in this order: 1,2,3,4,5,6,7,8,9,12,13,14,15,16,10,11.