Fig. 2
From: Effects of core stability and feedback music on upper body mediolateral movements during cycling
Schematic diagram of the self-developed system for measuring head angles and providing feedback music. A high-resolution inertial measurement unit (IMU) sensor was embedded in a left-side wireless earbud. IMU output was transferred to a mobile app in real time via Bluetooth. The mobile app calculated the head angle based on the accelerations provided by the IMU output. When the head angle was less than the predefined threshold, participants could listen to music from both earbuds. Otherwise, the wireless earbud on the side of the head tilt was muted