Development of FBG pressure sensors using FDM technique for monitoring sleeping postures

Abstract There are various methods used in 3D printing technology for its molding, prototyping, and fabrication applications, but fused deposition modeling (FDM) is most famous for its customized uses. In this research work, fiber Bragg grating (FBG) based pressure sensors were fabricated by embedding FBG sensors through the FDM process and Polylactic Acid (PLA) raw material was used during the fabrication of the pressure sensor. These FBG pressure sensors were placed into the smart bed for monitoring the sleeping postures. The loading and unloading tests were conducted for validating this new FBG pressure sensor. The Calibration tests showed that the maximum applied load on the pressure sensor was categorized by a measurement pressure range of ±58−352 N and the measurement sensitivity of two FBG sensors was around 0.00053 nm/N and 0.0012 nm/N. It is found that the most significant error of the FBG sensor is 13.3 % carrying out the vertical load of 0.35 K N. The measured wavelength changes exhibit a step-by-step increase and decrease during the sleeping postures which also agrees with the calibration data, and the measurement sensitivity of both FBG sensors remained approximately 0.00315 nm/N and 0.008 nm/N. The absolute errors of the sensor were less than 4% against the applied load during sleeping postures. FMD process is a new alternative method for its fast and straightforward embedment of FBG sensors fabrication for numerous applications. It is also initiated that FBG sensors can be adequately protected with molten PLA raw materials without losing their sensing performance and damage which has the advantage of easily washing smart sensors.