{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T18:00:03Z","timestamp":1773856803943,"version":"3.50.1"},"reference-count":29,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2017,3,12]],"date-time":"2017-03-12T00:00:00Z","timestamp":1489276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We present here the design and fabrication of a self-powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor\u2019s capacitance (measured in a laboratory prototype) increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of     S = 15.5     pF per unity change. Repeatability tests for capacitance measurement showed that the     \u03b8 v     sensor\u2019s root mean square error is 0.13%. The average current consumption of the system (sensor and signal conditioning circuit) is less than 1.5    \u03bc   A, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC\/DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested.<\/jats:p>","DOI":"10.3390\/s17030575","type":"journal-article","created":{"date-parts":[[2017,3,13]],"date-time":"2017-03-13T10:26:18Z","timestamp":1489400778000},"page":"575","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["A Self-Powered and Autonomous Fringing Field Capacitive Sensor Integrated into a Micro Sprinkler Spinner to Measure Soil Water Content"],"prefix":"10.3390","volume":"17","author":[{"given":"Eduardo","family":"Da Costa","sequence":"first","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nestor","family":"De Oliveira","sequence":"additional","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fl\u00e1vio","family":"Morais","sequence":"additional","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"},{"name":"Faculty of Science and Engineering, S\u00e3o Paulo State University J\u00falio de Mesquita, Tup\u00e3, SP 17602-496, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pedro","family":"Carvalhaes-Dias","sequence":"additional","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"},{"name":"Department of Electrical Engineering, Paran\u00e1 Federal University of Technology\u2014UTFPR, Corn\u00e9lio Proc\u00f3pio, PR 86300-000, Brazil"},{"name":"Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Barcelona 08930, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7794-6003","authenticated-orcid":false,"given":"Luis","family":"Duarte","sequence":"additional","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"},{"name":"Department of Electrical Engineering, Paran\u00e1 Federal University of Technology\u2014UTFPR, Corn\u00e9lio Proc\u00f3pio, PR 86300-000, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreu","family":"Cabot","sequence":"additional","affiliation":[{"name":"Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Barcelona 08930, Spain"},{"name":"Instituci\u00f3 Catalana de Recerca i Estudis Avan\u00e7ats (ICREA), Pg. Llu\u00eds Companys 23, Barcelona 08010, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J.","family":"Siqueira Dias","sequence":"additional","affiliation":[{"name":"Department of Semiconductors, Instruments and Photonics, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP 13083-820, Brazil"},{"name":"Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Barcelona 08930, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,3,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Rivers, M., Coles, N., Zia, H., Harris, N.R., and Yates, R. (2015, January 13\u201315). How could sensor networks help with agricultural water management issues? Optimizing irrigation scheduling through networked soil-moisture sensors. 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