Firmware-72 Function-004

ABSOLUTE (4, 04h)

The absolute function provides a way to convert signals that vary around a center value (such as from accelerometers and physiological sensors) to a value from zero. The following methods can be selected using the FUNCTION command’s parameter values FP1 and FP2:

FP1

0xxxxxxx:

xxxxxxx = [0..127]; Offset high bits

FP2

00000yyy:

yyy = [0..7]; Offset low bits

The offset is calculated as a 10-bit value represented by xxxxxxxyyy.

Example:

In order to output the value generated by a sudden motion of a GForce3D-6 sensor as a MIDI controller 64 message, the following messages are sent (see also the EDIT CONFIG command):

|240, 125, 0 {DEV}, 8 {FUNCTION}, 0 {input}, 0 {offset least significant bits}, 4 {absolute function}, 64 {offset MSB}, 247 (F0h, 7Dh, 00h, 08h, 00h, 00h, 04h, 40h, F7h)

|240, 125, 0 {DEV}, 106 {EDIT CONFIG}, 1 {configuration number}, 0 {input}, 48 {control-change message}, 64 {controller number}, 34 {peak detection with end notification}, 1 {threshold}, 64 {top}, 0 {noisegate}, 0 {time window}, 247 (F0h, 7Dh, 00h, 6Ah, 01h, 00h, 30h, 40h, 22h, 40h, 7Fh, 00h, 00h, F7h)

The threshold value may need adjustment to properly capture the signal peaks.