Abstract: An implantable fluid operated device may include a fluid reservoir configured to hold fluid, an inflatable member, and a pump assembly configured to transfer fluid between the fluid reservoir and the inflatable member. The pump assembly may include one or more fluid pumps and one or more valves. One or more sensing devices may be positioned within fluid passageways of the fluid operated device. The electronic control system may control operation of the pump assembly based on fluid pressure measurements and/or fluid flow measurements received from the one or more sensing devices. The pump assembly may include a piezoelectric pump. The one or more sensing devices may include one or more pressure transducers positioned in the fluid passageways, one or more strain gauges measuring deflection of piezoelectric elements, voltage input/output at one or more piezoelectric elements, and other types of sensing devices.