The overall project involves the development of a miniaturized measuring device, the photo-pllethysmograph (PPG), which allows the measurement of heart rate by pulsatile pathways and the observation of cardiovascular signals in order to improve patient management. The idea is to have a measuring device that continuously and accurately monitors patient constants. In particular, our device should be non-invasive. Indeed, our project responds to a need on the part of caregivers to replace the catheters used in the operating room because they are sometimes responsible for post-operative complications as well as disturbances during care. Our miniaturized sensor will therefore be in the form of a ring that will collect information on beats per minute, oxygenation rate and pulse wave characteristics (systole, diastole).