{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T16:46:24Z","timestamp":1768409184098,"version":"3.49.0"},"reference-count":56,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,1,20]],"date-time":"2022-01-20T00:00:00Z","timestamp":1642636800000},"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>Multi-converter piezoelectric harvesters based on mono-axial and bi-axial configurations are proposed. The harvesters exploit two and four piezoelectric converters (PCs) and adopt an impinging spherical steel ball to harvest electrical energy from human motion. When the harvester undergoes a shake, a tilt, or a combination of the two, the ball hits one PC, inducing an impact-based frequency-up conversion. Prototypes of the harvesters have been designed, fabricated, fastened to the wrist of a person by means of a wristband and watchband, and experimentally tested for different motion levels. The PCs of the harvesters have been fed to passive diode-based voltage-doubler rectifiers connected in parallel to a storage capacitor, Cs = 220 nF. By employing the mono-axial harvester, after 8.5 s of consecutive impacts induced by rotations of the wrist, a voltage vcs(t) of 40.2 V across the capacitor was obtained, which corresponded to a stored energy of 178 \u03bcJ. By employing the bi-axial harvester, the peak instantaneous power provided by the PCs to an optimal resistive load was 1.58 mW, with an average power of 9.65 \u03bcW over 0.7 s. The proposed harvesters are suitable to scavenge electrical energy from low-frequency nonperiodical mechanical movements, such as human motion.<\/jats:p>","DOI":"10.3390\/s22030772","type":"journal-article","created":{"date-parts":[[2022,1,20]],"date-time":"2022-01-20T22:51:06Z","timestamp":1642719066000},"page":"772","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Wearable Ball-Impact Piezoelectric Multi-Converters for Low-Frequency Energy Harvesting from Human Motion"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2387-0397","authenticated-orcid":false,"given":"Alessandro","family":"Nastro","sequence":"first","affiliation":[{"name":"Department of Information Engineering, University of Brescia, 25123 Brescia, Italy"}]},{"given":"Nicola","family":"Pienazza","sequence":"additional","affiliation":[{"name":"Department of Information Engineering, University of Brescia, 25123 Brescia, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5696-4138","authenticated-orcid":false,"given":"Marco","family":"Ba\u00f9","sequence":"additional","affiliation":[{"name":"Department of Information Engineering, University of Brescia, 25123 Brescia, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3197-6009","authenticated-orcid":false,"given":"Pietro","family":"Aceti","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, Politecnico di Milano, 20133 Milano, Italy"}]},{"given":"Markku","family":"Rouvala","sequence":"additional","affiliation":[{"name":"Huawei Technologies Oy, 00180 Helsinki, Finland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4271-9190","authenticated-orcid":false,"given":"Raffaele","family":"Ardito","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, Politecnico di Milano, 20133 Milano, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3310-7715","authenticated-orcid":false,"given":"Marco","family":"Ferrari","sequence":"additional","affiliation":[{"name":"Department of Information Engineering, University of Brescia, 25123 Brescia, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1285-2724","authenticated-orcid":false,"given":"Alberto","family":"Corigliano","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, Politecnico di Milano, 20133 Milano, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3949-9975","authenticated-orcid":false,"given":"Vittorio","family":"Ferrari","sequence":"additional","affiliation":[{"name":"Department of Information Engineering, University of Brescia, 25123 Brescia, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,20]]},"reference":[{"key":"ref_1","unstructured":"Grand View Research (2022, January 13). 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