Input Interface with Touch and Non-touch Interactions using Atmospheric Pressure for Hearable Devices

A hearable device is a wearable computer that is worn on the ear. In addition to offering conventional music listening functions when utilized as earphones, a hearable device can be linked to smartphones and various onboard sensors to recognize user actions and voice assistants. Although some devices recognize command operations when the earpiece is touched with a hand directly, there are limitations related to the shape of the earpiece and the problem of false recognition that occurs when the earpiece is touched unintentionally. Hands-free input methods utilizing voice assistants and acceleration sensors that measure head movement are available, but these run into problems such as low command recognition accuracy due to noise in public spaces and low social acceptability. In this study, we implement a device that measures the atmospheric pressure in the ear canal and around the ear by installing an atmospheric pressure sensor inside canal-type earphones. We propose a method that recognizes 12 types of gesture based on the pattern of pressure change caused by pressing and releasing the earphone with a finger (touch interaction) and by covering the auricle with a hand and putting pressure on it (non-touch interaction). In our method, six types of gesture are performed with two different interaction methods. We evaluated the recognition accuracy of each gesture by having five participants perform each gesture 50 times. Our findings showed that the ``quick press and quick release'' gestures were recognized with 0.99 accuracy for touch and 0.82 for non-touch.