External diagram of the earable ZEN. The earable ZEN is used by attaching the ear sensor to the left ear and winding the neck belt around the neck. The ear sensor measures deep mouth breathing (movement simulating disturbance in breathing) and nods (movement simulating disturbance in posture). When mouth breathing or nods are detected, the actuator built into the neck belt is activated, and a light vibration is applied to the left side of the neck. This vibration communicates to the subject that “there was a disturbance in breathing or posture.” The neck belt has a two-layer structure, and the actuator is embedded within the first layer (surface layer) and the second layer. The photograph of the actuator in the figure has the first layer peeled away so the actuator can be seen. The ear sensor and neck belt can be attached while wearing a variety of clothing, such as formal zazen clothes (stole), a T-shirt, or a collared shirt.