This study presents a multifunctional piezoelectric sensor with a self-adhesive multilayer nanofilm made via electrospinning for long-term biomechanical monitoring. It features an ABS/PVA self-adhesive substrate, a NiO/BaTiO₃-doped P(VDF-TrFE) layer, and PVD-deposited Au electrodes. NiO/BaTiO₃ enhances β-phase crystallinity, boosting the piezoelectric coefficient (d33) 13-fold. The sensor shows strong skin adhesion, mechanical durability, and stable, sensitive responses under bending and compression, making it ideal for wearable and bio-integrated sensing.