Cerebrospinal fluid (CSF) shunting is the principal treatment available for hydrocephalus. Although treatment efficacy is completely dependent on CSF flow through the device, current shunts do not provide any noninvasive means for monitoring the flow of CSF. To address this void in shunt technology, Eunoe is developing an implantable CSF shunt monitor that is designed to measure the rate of CSF flow noninvasively through implanted shunts. Currently, there are approximately 100,000 CSF shunts implanted or replaced annually worldwide. CSF shunts consist of an inflow catheter, most often positioned in a lateral ventricle, connected to a valve, and attached to an outflow catheter that drains into a lower body cavity, most often the abdomen. Shunts, which have a fifty-year history of use in hydrocephalus, are prone to dysfunction. In pediatric series, shunt failure ranges from 25 percent to 40 percent within twelve months of surgery, with a 4-5 percent risk for each year thereafter. Mechanical or functional failure, with inadequate CSF flow, account for the vast majority of complications. Invasive methods for assessing CSF flow through a shunt, """"""""shuntograms,"""""""" are costly, time consuming, and place the patient at risk of central nervous system infection. Shunt failure is most often detected by return or worsening of neurologic symptoms. In hydrocephalus, undetected shunt dysfunction can lead to permanent neurological damage or death. The Eunoeflow monitoring device is being designed to monitor flow both in existing CSF shunts and for incorporation into new shunt implants. This Phase 1 R&D plan focuses on development of the breadboard phase of the Eunoeflow sensor. This phase of the development cycle will be completed when a breadboard is successfully tested and found to meet the performance specifications. It therefore incorporates the design, fabrication, and validation of all test systems necessary to validate this performance. The performance specifications are a subset of the operational engineering specifications related to device performance, exclusive of issues associated with size, or materials.