Pulse oximetry is a standard non-invasive method of measuring blood oxygen saturation (SpO2). In developing countries, pulse oximeters are rare because of expense and electricity requirements. Our ECEM group has developed the Phone Oximeter, which uses a cell phone (widely available in developing countries) to compute and analyze information from a pulse oximeter sensor. To further reduce costs, we use the integrated flashlight of a cell phone's camera to extract SpO2 (Camera Oximeter), eliminating the need for external hardware. This study aims to calibrate the Camera Oximeter by exposing 30 healthy adult volunteers to various altitudes in UBC's hypoxia chamber.