Fundamental Development of Ultrasonic Information Transmission System for Wearable Devices

A wearable device is an electronic device miniaturized to a wearable size with computing and wireless communication functions. In this study, we have applied a communication system using ultrasonic waves to a wearable device. Ultrasonic waves are safe for the human body and do not cause the malfunction of electronic equipment. In addition, communication using ultrasonic waves is effective for preventing "skimming" because ultrasonic waves can transmit through the human body and have a large attenuation in air. Wearable devices can also be used in areas where electromagnetic waves are limited. We have developed an experimental prototype device. The prototype contains a one-chip microcomputer used to verify the size and battery consumption of the wearable device. As a result, the developed prototype realized bidirectional communication with a suitable device size and power consumption. The communication speed corresponds to 250 kbps. This value is equivalent to that of a conventional IC card system using electromagnetic waves. With this proposed system, we can achive various practical applications that can maintain absolute privacy while transmitting information through the human body.