Research on Smart Mattress Based on Fiber Unbalanced Sagnac Loop

Abstract

Because the contact vital sign detection system is monitored through skin contact, it affects the user’s comfort and causes inconvenience. And most of the non-contact equipment is not high precision, or the cost is too high. To solve the above problems, this article is based on the physiological activity of slight vibration in multimode optical fiber micro bending deformation which result in the change of light intensity principle, considering the structure of the optical fiber Sagnac loop sensor has simple structure, low cost, but the signal to noise ratio is poor and is not sensitive to low frequency signal, this paper designed a based on intelligent mattress of non-equilibrium sagnac loop structure. The mattress can obtain the heart impact map signal in real time by changing the small light intensity, and obtain the heart rate, respiration rate and other information through the algorithm processing the signal. Mattress in the design of the sensing optical fiber module will be connected to two different types of optical fiber of Unbalanced Sagnac loop structure, solve the balance Sagnac loop structure of optical fiber access signal noise is bigger, poor sensitivity were weakness, go through the serpentine line way of embedded mattress, and using the mattress cover material for optical fiber micro bending cycle critical mechanical adjustment cycle, the mattress is of high sensibility. Cardiac and respiratory signals obtained in the laboratory were compared with those obtained from the balanced Sagnac loop, and through the fast Fourier transform (FFT) in frequency domain signal is analyzed, the vital signs of signal more clearly this mattress stable and less noise, change the tester for many times after tests, get the signal of high accuracy, the error is very small. The experiment shows that the mattress can realize the non-sensory vital signs signal detection, convenient for users to monitor their physical conditions in real time in daily work and life, and can timely notify the family members and medical staff in emergency, to avoid the occurrence of accidents.