Research On The Weaving Method Of Photoelectric Sensors In Smart Wearables

With the change of lifestyle and the progress and development of science and technology,people pay more and more attention to health,so intelligent textiles emerge as the times require that physiological monitoring can be integrated.Such as real-time monitoring of ECG signal,heart sound signal,temperature and other physiological indicators,in order to timely report the disease to patients and their families.Firstly,the conductive silver-plated nylon yarn was used as the basic material,and five kinds of fabric electrodes were woven by weaving process,including electrode size,electrode structure,electrode thickness,electrode weft density and electrode shape.The AC impedance,open circuit voltage,static ECG signal,dynamic ECG signal and signal-to-noise ratio are tested and analyzed.The results show that when the diameter of the fabric electrode is 4cm,the weave structure is 12 / 5 weft satin,the weft density is 460 pieces / 10 cm,the thickness is single-layer fabric,and the shape is circular,the AC impedance of the fabric electrode is the smallest and the ECG signal quality is the best.According to the results,the integrated molding of wearable breast belt fabric electrode was realized by using semi-automatic jacquard machine.Without clipping,the accuracy and integrability of ECG signals are improved,and the roundness is corrected.Secondly,fiber Bragg grating cylindrical temperature sensor and fiber Bragg grating circular heart sound sensor are implanted into the fabric to ensure the comfort of the fabric and the accuracy of the measurement signal.With regard to fabric comfort,the effects of fabric weave,weft material and warp density are discussed by orthogonal experiment.The results show that the comfort parameters of the fabric are 3 / 1 Twill,polyamide / spandex coated yarn and 240 warp density / 10 cm.On the premise of ensuring comfort,the cylindrical temperature sensor is implanted into the designed cylindrical double-layer hollow fabric.In the weft at the sensor position,1:0,1:1,1:2and 1:3 super shrinkage polyester yarns are introduced to heat treat the fabric.With the increase of the proportion of super shrinkage polyester,the coverage rate of the fabric increases from 81.2% to 98.7%.When the coverage ratio is 94.1%,i.e.,the ratio of polyamide spandex coated yarn to super shrinkage polyester yarn is 1:2,the measured temperature is closer to that measured by bare sensor.At the same time,using jacquard textile technology,the circular heart sound sensor is implanted into the designed circular double-layer hollow tissue,and the heart sound signal is monitored.The results show that the positions of the first and second heart sounds measured by the sensor are basically the same before and after the fabric implantation,and the heart sound signal only decreases slightly after the fabric implantation.The wearability of hard sensor is realized,and the accuracy and stability of measurement are also ensured.