Design of equipment for advanced PPG research

The development of a high-quality photoplethysmographic sensor (PPG) is one partial tasks of our research of telemedicine equipment. This area become very critical during recent pandemic. We have previously worked on the development of patches that monitor the temperature of people in the hospital environment. The situation came up with the idea of fitting this patch with a PPG for determining the heart pulse and the blood oxygen saturation. Unfortunately, when using a PPG, we found that it would not be such an easy task and we need an extensive optimization. Each part of the human body requires a specific geometry and combination of LEDs and photodetectors, different LED intensities etc. For this reason, we created universal and advanced PPG sensor. The device contains 15 three-color LEDs, 2 photodetectors, an ambient light sensor, an accelerometer, and wireless communication. In this article, we focus only on the hardware part.