Proposal and Evaluation for Miniaturization and Power Saving of Sensor Network Terminals

Nose, Hiroaki; Bao, Miao; Mizuta, Kazumasa; Yoshikawa, Yasushi; Kunimune, Hisayoshi; Niimura, Masaaki; Fuwa, Yasushi

doi:10.1587/transfun.e93.a.1735

Cited by 5 publications

(1 citation statement)

References 3 publications

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“…Figure 8(b) shows the area where the sensors were inserted and the waterproof box used to store the wireless transmitter and batteries. The wireless transmitter (21,22) used a radio frequency of 429 MHz because the influence of trees on a 429 MHz radio signal is smaller than that if a higher radio frequency is used. (23) The SiO x and SiN x sensors performed measurements for around five months.…”

Section: On-site and Long-term Measurement On Slope Of Mountainmentioning

confidence: 99%

Fabrication of Impedance Sensor with Hydrophilic Property to Monitor Soil Water Content for Slope Failure Prognostics

Futagawa

Ito

Ogasahara

et al. 2021

Sensors and Materials

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To minimize the damage caused by slope failure, knowledge of the increase in water content in mountain soil is important. Our group has been studying miniaturized impedance sensors for multipoint measurements in soil. Conventional sensors with a SiN x top film sometimes cannot detect changes in the water content in soil resulting from rain. Experiments on the slide distances of water droplets were performed using SiO x and SiN x films. As the slide distance of the SiO x film was shorter than that of the SiN x film, it was confirmed that the SiO x film is more hydrophilic than the SiN x film. To improve contact characteristics between the sensor surface and free water in soil, we covered our conventional sensor chip with a hydrophilic SiO x film. As a contact property test, the sensor chip measured the impedances of model soils. The proposed sensor achieved stable contact with the free water in the soil. Moreover, the chip operated for a long period of time on a mountain slope. The sensor could measure nearly theoretical outputs in response to rainfall. Thus, we succeeded in fabricating a stable soil monitor sensor with a hydrophilic SiO x film.

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Section: On-site and Long-term Measurement On Slope Of Mountainmentioning

confidence: 99%