Our project exploits the absorption spectrum of hemoglobin to calculate oxygen saturation. Oxygen saturation is defined as the amount of oxygen dissolved in the bloodstream. Two different wavelengths of light are passed through a finger, and oxygen saturation is calculated based on the absorption of the light. The absorption of light is affected by the concentration of Hemoglobin and Deoxyhemoglobin. We are using infrared(940 nm) and red (660 nm) light in our project. The absorption curves of hemoglobin and deoxyhemoglobin (shown below) differ vastly at these wavelengths which make them good choices. Our setup detects the amount of light leaving the finger at both wavelengths, and uses this to calculate absorption. Based on the amount of each wavelength that is absorbed, we use mathematical formulas to calculate the oxygen saturation.