A device includes a wirelessly enabled energy harvesting device, an energy storage component, a DC-DC converter, and a functional circuit. The energy storage component is electrically coupled to the wirelessly enabled energy harvesting device for storing energy harvested by the wirelessly enabled energy harvesting device from a wireless transmitting device positioned adjacent to the device. The DC-DC converter is electrically coupled to the energy storage component for receiving a voltage output from the energy storage component and converting the received voltage output to a second voltage level to provide power to one or more components of the device. The functional circuit is for measuring a concentration of a substance in a fluid sample. The functional circuit is coupled to the DC-DC converter such that the functional circuit obtains at least a portion of the power provided by the DC-DC converter.
