The design of a real-time accelerometer-based sleeping position monitoring system and its application on obstructive sleep apnea syndrome

In this paper, we design and present a novel real-time sleeping position monitoring system. The sensing modules composed of 3-axis accelerometers are placed on object's forehead and chest to monitor the object's position during sleeping by calculating the angles between gravity vector and its three axes. System is driven by an inexpensive and low power microcontroller. In this system, we implement a proposed novel CORDIC-based algorithm on the embedded microcontroller so that the system is capable of transferring the raw data of the accelerometer from motion domain to angular domain in-line, and the system can provide the inclination or tilt angle information by itself in real-time. The sleeping position information is integrated into polysomnography (PSG) to cooperate the study of obstructive sleep apnea (OSA) syndrome.