Real Time Perspiration Measurement using a Hetero-Core Structured Fibre Optic SPR Sensor

Masahiko Shiraishi, Michiko Nishiyama, and Kazuhiro Watanabe


Noninvasive measurement, Optical fibre sensor, Surface plasmon resonance, Perspiration measurement


We have proposed perspiration monitoring application of hetero-core structured fibre optic Surface Plasmon Resonance (SPR) sensor that can detect refractive index changes transformed as optical power changes. This sensor has sensitivity of refractive index from air to water and capability of measuring relative humidity. In the experiments, the sensor was settled in a small space of 10 ml and used to measure level of human perspiration in the small space. The palms were set on 1cm2 square hole of the small space, as a result, the sensor caught the sweat of the examinee that got through the small space. Furthermore, four subjects were tested for perspiration monitoring from the subject’s palm. The sensor could detect difference of sweat level. The optical loss changes of subjects -A, -B, -C and -D were 1.201, 0.837, 0.980 and 0.949 dB, respectively. Additionally, perspiration was measured in conditions of before and after running in the same subject. The optical power losses of before and after running indicated to be different of 1.201 and 1.364 dB, respectively. Additionally, releasing the palm from the square hole caused air infiltration in the small space, therefore, the perspiration sensor could be repeatedly used in daily activity.

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