Eowave Eobody1 - Manual (Page 16)

16
IV.5. - Use eo•body Editor • user’s manual
manual ©eowave/Ircam 2003
This is one of the most important configuration parameters, since it
determines which type of MIDI message the device is going to send
in response to variations in a particular analogue input.
eo•body is
capable of generating 6 different messages:
• CC: Control number change (Control change)
• Note: Note on Trigger
• PC:
Program change
• PB: Pitch bend (Variation in pitch)
• ATp: Polyphonic aftertouch (Polyphonic pressure)
• ATm: Monophonic aftertouch (Channel pressure)
Those two parameters specify how the real range of an analogue
input can be mapped on a seven bit MIDI value. As a matter of fact, a
sensor does not necessarily have a range equal to the reference vol-
tage of the Analogue to Digital Converter. We have implemented a
custom scaled zoom on the digital value to take advantage of the 10
bit resolution of the A/D converter. First, the voltage reference has to
be set to the largest range among the sensors connected to the unit.
Then, the user can select the sensor’s range within the 10 bits dyna-
mic by specifying a window size and an offset. The selected range can
then be converted into 7 bits MIDI data without greatly increasing the
quantification step, as shown in the following illustration.
0
127
1023
Digital value
(10 bits) MIDI data
(7 bits)
MIDI conversion
zoom setting
=
real sensor range
Offset
Zoom & Offset
Zoom:
max/mid/low/off
Offset: 0 to 895
(depending on
zoom level)
Type
This is the type of message which will likely be most often
used for controlling sound parameters. The value of the ana-
logue signal acts directly upon the value of a MIDI controller, using a
MIDI controller Value Change message (control change). The number
of the controller can be set by the user. If 10 bits resolution is selec-
ted, this message will actually send two Control Change messages.
The controller specified in the val field will send the 7 least significant
bits whilst the controller specified in the prm1 field will send the 3
most significant bits, on the same MIDI channel.
Control Change
CC