BLOOD PRESSURE METER USING NEAR-INFRARED SPECTROSCOPY SENSORS.

A blood pressure meter is designed by using near-infrared spectroscopy (NIRS). Blood pressure estimations are find by recording pulse wave velocity of blood traveling from the upper arm down to one\'s index finger. The heart contracts and relaxes, it pumps blood through the body, creating the pulse felt at different parts of the body. This pulse is a brief increase in blood flow that occurs continuously and can be detected as a periodic signal. Because NIRS can detect the amount of blood flow, when the pulse wave arrives at a certain point in the body, the amount of IR light reflected back out through the skin increases. The signal output from the IR sensor is therefore the pulse signal itself, if filtered correctly. Near-infrared spectroscopy (NIRS) is chose to measuring blood pressure through collecting data on pulse transit time between two points in the body. Read in data through two analog inputs on the controller, and calculate the time at which the pulse wave reached each location mentioned.