The operation of the monitoring system is kept simple
and consists of only three simple steps. Firstly, it uses 12
FBG sensors with different Bragg wavelengths, cascaded
along a single fiber. The 12 FBG sensors are mounted on
the surface of the bed to form a 34 matrix array (as
depicted in Fig. 2), and the bed is then covered by the usual
mattress. Each FBG sensor is specially packaged into an
arc-shaped elastic bending beam using some carbon fiber
reinforced plastic (CFRP) material, which ensures excellent
sensitivity and good linear translation from a lateral
force exerted to the apex of the sensor into axial strain of
FBG when a subject is on the bed. Secondly, the optical
interrogator is turned on, and the software application is
run to acquire all wavelength data of the sensors. Lastly,
the body movement and respiration pattern will be
captured and displayed once a patient lies on the bed, and intelligent algorithms will show the pressure distribution
contour and calculate the respiratory rate. When an
abnormal fall in the respiratory rate is detected, an alarm or
SMS will be sent to notify the caregiver for immediate
attention.