1. A device comprising: at least one of a sensor or an actuator; a processor; a network interface coupled to the processor and the at least one sensor or actuator, the network interface adapted for connection to a network, and including circuitry to receive power from a power signal provided over the network, and to demodulate a clock signal and a data signal from the power signal; and a housing that encloses at least a portion of the at least one sensor or actuator, the network interface, and the processor, the housing formed of a biocompatible material, and shaped and sized for implantation into a body; wherein the device is physically free of a power storage element.