The document describes the design and implementation of a low-cost pulse oximeter to measure blood oxygen saturation levels (SpO2) using an Arduino microcontroller and MAX30100 sensor. Key features include using the sensor and microcontroller to process signals and compute SpO2 levels, simulating the system in Proteus, and displaying results on a 16x2 LCD screen. The device aims to provide affordable home monitoring of oxygen levels, which is important for managing COVID-19 and other respiratory conditions.