Overview

Easy Pulse is a DIY pulse sensor that can be used for detecting the cardio-vascular pulse wave from a fingertip. It is designed for hobby and educational applications to illustrate the principle of photoplethysmography (PPG), which is a non-invasive optical technique of retrieving vital information about the cardiovascular system from the skin surface. It uses an infrared light source to illuminate the finger on one side, and a photodetector placed on the other side measures the small variations in the transmitted light intensity. The variations in the photodetector signal are related to changes in blood volume inside the tissue. The signal is filtered and amplified to obtain a nice and clean PPG waveform, which can be thus used to derive the instantaneous heart rate. The Easy Pulse sensor also provides a digital pulse output which is synchronous with the heart beat.