Piezoelectric Energy Harvesting System to Charge Batteries with the Use of a Portable Musical Organ. - Vega-Ávila, Josué Esaú; Anaya-Ruiz, Guillermo Adolfo; Román-Godínez, José Joel; Esquivel-Barajas, Gabriela Guadalupe; Ortiz-Marín, Jorge; Gudiño-Valdez, Rogelio; Aguilar-Rodríguez, Hilda (Energies (19961073), 2025)