Firmware-72 Function-010

ABS-BPM

The ABS-BPM function, when used together with the Peak feature that can be set using the EDIT CONFIG command, measures the frequency in beats per minute (BPM) of successive peaks as defined in the EDIT CONFIG command. The offset value is subtracted of the sensor value, after which the absolute value is taken, and after which smoothing can be applied. If the Peak feature is then enabled using the EDIT CONFIG command the frequency of peaks is measured in BPM. The ABS-BPM function has the following parameter values FP1 and FP2 that can be set with the FUNCTION command:

FP1

0xxxxxxx: xxxxxxx: [0..127]; Offset

The offset MSB is multiplied by 8 and subtracted from the sensor value represented as a 10-bit value.

FP2

0m00yyyy:	yyyy: 0; No smoothing
	yyyy: [1..15]; Smoothing
	m = 0; Monitor off
	m = 1; Monitor on

When the monitor is enabled, the sensor value is output as a separate MIDI message after the smoothing function (if enabled) but before being processed as configured by the EDIT CONFIG command. The MIDI message is the same as set by the EDIT CONFIG command but, if note or controller messages are used, the note or controller number is incremented by one. If another MIDI message is used the MIDI channel is incremented by one.

Example:

In order to output the frequency in BPM of a BioVolt sensor connected to input 1 of the USB-microDig (in stand-alone mode with USB-microMIDICable and battery-powered so as to prevent electrical shock) as MIDI controller 64 messages, the following messages are sent (see also the EDIT CONFIG command):

240, 125, 0 {DEV}, 8 {FUNCTION}, 0 {yyy = 0}, 100 {smoothing}, 10 {biobeat function}, 64 {offset}, 247 (F0h, 7Dh, 00h, 08h, 00h, 64h, 0Ah, 40h, F7h)

240, 125, 0 {DEV}, 106 {EDIT CONFIG}, 1 {configuration number}, 0 {input}, 48 {control-change message}, 64 {controller number}, 34 {peak detection and smoothing}, 64 {threshold}, 127 {top}, 0 {noisegate}, 0 {time window}, 247 (F0h, 7Dh, 00h, 6Ah, 02h, 00h, 30h, 40h, 22h, 40h, 7Fh, 00h, 00h, F7h)

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