This paper presents a comprehensive review of bending sensors and their classifications. The main focus is on advancements in the design of optical fibre bending sensors based on fibre Bragg gratings (FBGs). Various measurement principles employed in optical fibre bending sensors are analysed, highlighting their respective advantages and limitations. Particular attention is given to sensors utilising long period gratings (LPGs), Tilted fibre Bragg gratings (TFBGs), and multicore (MCF) fibre structures, which demonstrate significant potential for the development of highly sensitive and compact bending sensing systems. 

This publication investigates the influence of external factors on the readings of heat flow sensors located at different distances from the heat source. ARIMA models with Gaussian distributions and t-distribution were used for the analysis, as well as Quantile-Quantile plots to assess the appropriateness of the distribution of model residuals. It was found that the influence of external factors varies significantly depending on the distance of the sensor to the heat source, which is confirmed by the results of the analysis. Sensors located closer to the heat source showed greater sensitivity to environmental changes, while sensors at a greater distance showed more stable readings. The obtained results emphasize the importance of taking into account external factors during the placement and operation of heat flow sensors to ensure maximum measurement accuracy.