From a thought experiment to a journal paper. Problem: the light sources in oximeters burn a lot of power. Crazy idea: what if we don’t use those light sources, and use ambient light instead. Turns out you can measure oxygen saturation using ambient light. Find out more about our project:

Paper title: Pulse Oximetry Using Organic Optoelectronics under Ambient Light

Abstract: Light absorption in oxygenated and deoxygenated blood varies appreciably over the visible and near-infrared spectrum. Pulse oximeters use two distinct wavelengths of light to measure oxygen saturation SpO2 of blood. Currently, light-emitting diodes (LEDs) are used in oximeters, which need additional components to drive them and negatively impact the overall size of the sensor. In this work, an ambient light oximeter (ALO) is demonstrated, which can measure photoplethysmography signals and SpO2 using various kinds of ambient light, avoiding the use of LEDs. Spectral filters are combined with organic photodiodes to create the ALO with sensitivity peaks at green (525 nm), red (610 nm), and near-infrared (740 nm) wavelengths. Finally, the wearable ALO is used to measure photoplethysmography signals and SpO2 on the index finger in different indoor and outdoor lighting conditions and the measurements are validated with commercial pulse oximeters under normal and ischemic conditions.

Publication:

  1. Pulse Oximetry Using Organic Optoelectronics under Ambient Light Donggeon Han, Yasser Khan, Jonathan Ting, Juan Zhu, Craig Combe, Andrew Wadsworth, Iain McCulloch, and Ana C. Arias Advanced Materials Technologies, 2020 n/a, n/a. [Abstract] [Bibtex] [PDF]