Near-Ultrasonic Communications for IoT Applications using Android Smartphone

Conventional wireless communication means for Internet of Things (IoT) devices and smartphones mostly rely on electromagnetic waves as the carrier of the information. Typical wireless communication protocols for IoT devices and smartphones include Wi-Fi, Bluetooth, NFC and other radio frequency enabled technologies, which may require additional dedicated transceivers and/or a dedicated router to establish the communication. An alternative method to communicate between two IoT devices is by establishing data transmission through acoustic waves. By utilizing ultrasound or near ultrasound acoustic waves for wireless communications, it allows data transmission between nearby devices without the need of a router or a coordinator. In this study, we explore and seek alternative solutions for IoT devices to communicate using near-ultrasonic waves between two typical Android smartphones. This paper focuses on presenting the feasibility of such a system with Android smartphones as transceivers for near-ultrasonic data communication using their built-in microphones and speakers. Different techniques on encoding, transmitting, receiving and decoding basic text messages are presented by verifying the frequency response of the devices and achieving the communication via Amplitude-Shift Keying (ASK) and Frequency-Shift Keying (FSK) modulation methods.