That’d be easy enough…
The Keys: The 24 keys (not including the Aux button on the far left) transmit “note on” messages. The leftmost key uses note number 60 (“middle C,” or “C3” in most MIDI systems), and the rightmost key uses note number 83 (“B4”), with all keys in between following this scheme. When a key is pressed down, a “velocity” of 100 is transmitted. When a key is released, a “velocity” of 0 (zero) is sent.
The Knobs: Knobs 1, 2, 3, and 4 transmit “control change” messages using controller numbers 21 , 22 , 23 , and 24 , respectively. The full range of controller values (from 0 to 127 ) is utilized.
The Aux Button: The Aux button transmits momentary “control change” messages using controller number 25 . When the button is pressed down, a controller value of 100 is transmitted. When the button is released, a controller value of 0 (zero) is sent.
The Pedal Port: A pedal connected to the Organelle’s Pedal port transmits two sets of “control change” messages.
Controller number 64 transmits a controller value of 0 (zero) for any received signal below 64 , and a controller value of 127 is sent for any received signal of 64 or above. This discrete, threshold behavior is particularly good for sustain-/damper-style pedals.
Controller number 26 transmits continuous values. While the general range would be from 0 (zero) to 127 , the exact range of values may vary based on the pedal connected. This continuous behavior is ideal for an expression-type pedal.