Identifying human body states by using a flexible integrated sensor

Flexible sensors are required to be lightweight,compatible with the skin,sufficiently sensitive,and easily integrated to extract various kinds of body vital signs during continuous healthcare monitoring in daily life.For this,a simple and low-cost flexible temperature and force sensor that uses only two carbon fiber beams as the sensing layer is reported in this work.This simple,flexible sensor can not only monitor skin temperature changes in real time but can also extract most pulse waves,including venous waves,from most parts of the human body.A pulse diagnostic glove containing three such flexible sensors was designed to simulate pulse diagnostic methods used in traditional Chinese medicine.Wearable equipment was also designed in which four flexible sensors were fixed onto different body parts(neck,chest,armpit,and fingertip)to simultaneously monitor body temperature,carotid pulse,fingertip artery pulse,and respiratory rate.Four important physiological indicators—body temperature(BT),blood pressure(BP),heart rate(HR),and respiratory rate(RR)—were extracted by the wearable equipment and analyzed to identify exercise,excited,tired,angry,and frightened body states.

Fiber-junction design for directional bending sensors

Flexible sensors in wearable electronics have become increasingly multifunctional due to the development of materials synthesis and structure design.In particular,structural design can not only add capabilities to sensors fabricated from existing available and normal materials,but also offer opportunities for the fabrication of sensors with certain desired functions.Here,we designed a series of fiber-junction structure models,in which two fibers were simply hooked to each other to form a junction on a flexible printed circuit,for fabrication of directional bending sensors.The value and direction of bending angle are related to the change in electronic signal by a theoretical expression,allowing us to employ a simple and practicable method to use available conductive fiber materials to fabricate high-sensitivity,high-resolution and directional bending sensors.In addition,these models are generally applicable,which have broad combination with different conductive fiber,and corresponding bending sensors all possess capability of directional identification.Furthermore,the capability of identifying directional bending was demonstrated by human motion monitoring such as joint bending and muscle contraction.