Block diagram of the earable ZEN. The earable ZEN is comprised of an earphone-type ear sensor, an actuator attached to a neck belt, an embedded microcomputer programmed in the C language, a start/stop button, and a threshold adjust knob. An optical sensor (LED and phototransistor) and weight are attached to the ear sensor. The microcomputer, based on the principles shown in Figure 3
, where the variation in the measured values received from the ear sensor is greater than the threshold
stated in Section 2.2
, judges that “there was a disturbance in the breathing or posture” and activates the actuator attached to the neck belt. Threshold
is obtained using the method described in Section 2.2
, and this can be finely tuned using the threshold adjust knob. The earable ZEN can also start and stop operation using the start/stop button.