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.