The implemented sensors, here assigned as S025 and S050, havea total length of 5 m of optical plastic fiber, essentially composed bypolymethylmethacrylate. The sensing portion starts on one end ofthe fiber and has 2 m in length, with groves spaced at every 0.2 m.The diameter of the fiber employed was 1 mm (Avago TechnologiesHFBR-RUS100Z) and the groves had a depth of 0.25 mm in sensorS025 and 0.5 mm in sensor S050. The opposite extremity of the fiber(without grooves) was connected to the data acquisition system.