A Contactless Operating Method for a Smartphone by Irradiating Resonant Frequency Sound to a Built-in Capacitive Accelerometer

Accelerometers built into devices, such as smartphones and smartwatches, are used for applications including activity tracking and health management. A method has been proposed that intentionally modifies sensor output by irradiating sound waves, and research exists that applies this technique to embed arbitrary bit sequences into capacitive accelerometers. This paper proposes a method for real-time analysis and identification of bit sequences embedded in acceleration data. The proposed method enables contactless control of smartphones through the use of sound wave irradiation. In the evaluation experiment, the success rate of correctly launching the appropriate application for 4 to 8-bit sound wave patterns was measured. While Devices 1 and 3 achieved 100% accuracy under all conditions, Device 2 showed a tendency for the success rate to decrease as the number of bits increased.