A study for the development of PVDF vibration sensor and establishment of noise removal algorithm for snoring detection pillow

Sleep diseases such as snoring and sleep apnea is physically, mentally harmful and results serious health problems. Snoring is known for breathing noise caused by coupled oscillation of the airway as the air passes through the trachea, and sleep apnea is caused by upper airway blockage. In this study, a new sensing system and analysis algorithm were developed in order to detect correct snoring sounds under various sleep environments. Sensing system includes two PVDF vibration sensors inside the pillow. First PVDF sensor detects vibration transmitted through skull caused by snoring. Second PVDF sensor detects both snoring sounds and ambient noise. Two sensor outputs went through the conditioning circuits designed in house, and acquired using data acquisition system(Biopac Co.). Three volunteers were participated for the experiment under five different sleep conditions. Acquired signals from two PVDF sensors went through the established analysis algorithm, and compared for differentiating snoring sounds and noises. The results show that the energy of snoring signal showed more than 50% of ambient noises, which proves effectiveness of sensing system and analysis algorithm. Further study would be continued for more wide clinical studies with various environment noises. Based on this study, development of anti-snore pillow and sleep monitoring system for comfort sleep could be developed.