Figure 2.

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.