Development of pulse oximeter by using 32-bit arm based microcontroller

Pulse oximeter is medical equipment that is using non-invasive method for the calculation percentage of oxygen concentration in human blood. The technique used is based on the transmission of light through the finger and the calculation of the light intensity passing through the finger. The device uses red and infrared light - emitting diodes (LEDs) to transmit red and infrared lights and a photodiode for the receiver. The light pass through the finger is absorbed by hemoglobin in the blood vessel. The absorbance of the light by hemoglobin is calculated due to existence of AC and DC component from both red and infrared. The ratio of the AC and DC component then get to use for determining the percentage of oxygen concentration. In the thesis, pulse oximeter has been designed and realized. The design based on 32-bit ARM based microcontroller STM32F103c6. Also, developed pulse oximeter consists of LCD, basic electronic components, and red and IR sensor as MAX 30100. After obtaining the schematic drawing of the design, printed circuit board (PCB) drawing was completed and produced. After the mounting of the circuit elements on the PCB, embedded software developed with the C programming language has been downloaded in the chip. The results obtained from the tests have showed the success of the design. Both the heart rate and the oxygen concentration in the blood are displayed on the LCD. Normally, the oxygen level in the blood should be between 95% and 99%.