Unique activity-meter with piezoelectric poly(vinylidene difluoride) films and self weight of the sensor nodes

Hirofumi Nogami, Hironao Okada, Seiichi Takamatsu, Takeshi Kobayashi, Ryutaro Maeda, Toshihiro Itoh

研究成果: Contribution to journalArticle査読

11 被引用数 (Scopus)

抄録

We have developed piezoelectric switches for application in ultra low-power wireless sensor nodes to monitor the health condition of chickens. Using Pb(Zr0.52,Ti0.48)O3 (PZT) thin films, we have developed S-shaped PZT cantilevers with proof masses. Since the resonant frequency of PZT devices is approximately 24 Hz, we have utilized their superharmonic resonance to detect chicken movements with frequencies as low as 5- 15 Hz. By attaching sensor nodes to chickens, we successfully measured the activity of chickens. However, the PZT devices of other sensor nodes broke down. S-shaped PZT devices are adequate for low vibrations, but are beset by the structural problems of fragmentation upon impact. To address these problems, we examine a method of utilizing poly(vinylidene difluoride) (PVDF) films, which are tough and generate high piezoelectric output voltages under a large stress, as piezoelectric switches. We suggest that the self-weight of sensor nodes be used as the mass of the cantilevers of the PVDF films. One end of a PVDF film is fixed to the case of a sensor node, and the other end is attached to the sensor node. Since PVDF films are subjected to force generated by the self-weight of sensor nodes, high output voltages are expected. A result of measuring output voltages, we confirm the output voltages to be approximately the same as those of PZT devices below 15Hz at 0.5 m/s2 vibration, which is close to chicken movements. Thus, we consider that we have successfully fabricated a tough wireless sensor node for chickens, utilizing the features of PVDF films.

本文言語英語
論文番号09KD15
ジャーナルJapanese journal of applied physics
52
9 PART2
DOI
出版ステータス出版済み - 9 1 2013
外部発表はい

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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