A system includes bio-medical units and an electromagnetic signal generating unit. A bio-medical unit includes a power harvesting module, a wireless communication module, a processing module, and a functional module that performs physical therapy function and generates physical therapy data. The electromagnetic signal generating unit that includes at least one signal generating module and a plurality of near field communication (NFC) modules. The signal generating module generates one or more signals and an NFC module converts the one or more signals into a component of electromagnetic signal, which the power harvesting module converts into a supply voltage that powers the other modules of the bio-medical unit.
