DIY Pulse Oximeter using Arduino and Pulse Sensor

This DIY pulse oximeter uses an Arduino Nano as the central processing unit to measure your heart rate and blood oxygen saturation ($SpO_2$). The system relies on the MAX30100 Pulse Sensor, which uses optical sensors containing infrared and red LEDs along with a photodetector. When you place your finger on the sensor, it shines light through your skin and measures the amount of light reflected or absorbed by pulsating blood vessels. Because oxygenated and deoxygenated hemoglobin absorb different wavelengths of light, the sensor can calculate your blood oxygen levels based on these absorption changes over time. The Arduino Nano communicates with this sensor and processes the raw optical data to determine your pulse rate. To display the results visually, the project incorporates an SSD1306 OLED display, which connects to the Arduino using I2C communication (requiring pull-up resistors like the 4.7K resistor to ensure stable signal transmission). All these components are wired together on a breadboard for easy prototyping, and the code is uploaded to the Arduino using the Arduino IDE.