Pulse Oximeter and Heart Rate Sensor - MAX30101 & MAX32664 (Qwiic)
The Sparkfun Pulse Oximeter and Heart Rate Sensor is an I2C based biometric sensor, utilizing two chips from Maxim Integrated: the MAX32664 Biometric Sensor Hub and the MAX30101 Pulse Oximetry and Heart Rate Module.
The MAX30101 does all the sensing by utilizing its internal LEDs to bounce light off the arteries and arterioles in your finger's subcutaneous layer and sensing how much light is absorbed with its photodetectors. This is known as photoplethysmography. This data is passed onto and analyzed by the MAX32664 which applies its algorithms to determine heart rate and blood oxygen saturation (SpO2).
To get the most out of the sensor Sparkfun has written an Arduino Library to make it easy to adjust all the possible configurations.
More information is available on the website of Sparkfun.