We present a MEMS device fabricated in the SensoNor MultiMEMS process to replicate the tilt sensing function of the human vestibular system. Our device uses opaque fluid movement within a cavity to govern the amount of light that reaches strategically placed photosensing regions. In addition to the device we have included various structures so that we can determine the performance of various photodiode structures. The photodiodes were tested both to obtain their intrinsic current-voltage relationship without optical illumination and for their photo-sensitive characteristics by providing varying levels of optical excitation. The forward bias turn-on voltage was approximately 700 mV and varied across different device doping.