Design and Implementation of Pulse Oximeter Using Fuzzy Logic

Abstract

The pulse oximeter is the most used device due to be a non-invasive method in measuring the oxygen level in blood. In the pulse oximeter, red and IR (Infrared) LEDs (light emitting diode) sent signals to the photodiode. An equation or relationship between the ratio (R) of signals (red and IR) received by photodiode with the oxygen saturation value (SpO2) needs to model the value of blood oxygen saturation. R (ratio) value is calculated according to absorption rates of signals, which are sent by red and IR LEDs in finger mounted oxygen saturation sensor. The obtained R value has been used as the input to fuzzy logic then SpO2 value has been calculated. Also, a linear relationship between SpO2 and R values has been created with absorption coefficients using linear regression method and compared with SpO2 values calculated by fuzzy logic method.