In one aspect, the disclosure provides a pressure sensor that wirelessly provides force/pressure data to a wireless receiver. The pressure sensor includes a first fluid-responsive membrane configured to be exposed to a region, such as a body fluid, whose pressure is being monitored. A force transducer for measuring this pressure is movable toward and away from the flexible membrane and may be oscillated, either out-of-contact with the first fluid-responsive membrane or in-contact therewith, for static/dynamic pressure sensor calibration. An actuator for displacing/oscillating the force transducer is located within the internal housing. Specific pressure transducers, fluid drainage systems, implantable devices and (at least partially) external sensing devices are disclosed. Calibration techniques, including recalibration to adjust for device drift and to clear biofouling are disclosed.
