Research on intelligent mattress based on improved SMS structure sensing fiber

The contact-type vital signs detection system affects the user's comfort and causes inconvenience due to its monitoring through skin contact. And most of the non-contact equipment precision is not high, 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 results in the change of light intensity principle, considering the singlemode-multimode- singlemode(SMS) fiber of the structure of the sensor has simple structure, low cost, high sensitivity, but get the signal to noise is bigger, the accuracy is not high, this paper designs a kind of intelligent mattress based on modified SMS sensing optical fiber. The mattress can obtain ballistocardiogram signal in real time by changing the small light intensity, and obtain the heart rate, respiration rate and other information through the algorithm processing signal. In this design, the sensing fiber of the mattress is embedded in a small core fiber to solve the shortcomings of signal noise interference and instability obtained by the SMS structure fiber, and then it is embedded in the mattress by means of serpentine routing, and uses the covering material of the mattress adjusts the micro-bending period of the optical fiber to reach the critical mechanical period, so that the mattress has high sensitivity. Through in the laboratory and SMS type sensor for heart and breath signal are compared, and contrast and by Fast Fourier Transform (FFT) in frequency domain signal is analyzed, the vital signs of signal more clearly this mattress stable noise smaller, replace 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 detect non-sensory vital signs, facilitate the user to monitor his/her physical condition in real time in daily work and life, and timely inform the family members and medical staff in case of emergency, so as to avoid the occurrence of accidents.