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. While the latter does all the sensing, the former is an incredibly small and fast Cortex M4 processor that handles all of the algorithmic calculations, digital filtering, pressure/position compensation, advanced R-wave detection, and automatic gain control. It’s provided a Qwiic connector to easily connect to the I2C data lines but you will also need to connect to two additional lines. This board is very small, measuring at 1in x 0.5in (25.4mm x 12.7mm), which means it will fit nicely on your finger without all the bulk.
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). SpO2 results are reported as the percentage of hemoglobin that is saturated with oxygen. It also provides useful information such as the sensor’s confidence in its reporting as well as a handy finger detection data point.
Key Features
SparkFun Pulse Oximeter and Heart Rate Sensor

MAX30101 and MAX32664 sensor and sensor hub
Qwiic connectors for power and I2C interface
I2C Address: 0x55

MAX30101 – Pulse Oximeter and Heart-Rate Sensor

Heart-Rate Monitor and Pulse Oximeter Sensor in LED Reflective Solution
Integrated Cover Glass for Optimal, Robust Performance
Ultra-Low Power Operation for Mobile Devices
Fast Data Output Capability
Robust Motion Artifact Resilience

MAX32664 – Ultra-Low Power Biometric Sensor Hub

Biometric Sensor Hub Solution

Finger-Based Algorithms Measure Pulse Heart Rate and Pulse Blood Oxygenation Saturation (SpO2)

Both Raw and processed data are available

Basic Peripheral mix optimizes size and performance

Resources

Schematic

Eagle Files

Board Dimensions

Hookup Guide

Datasheet(MAX30101)

Datasheet(MAX32664)

User Guide(MAX32664)

Arduino Library

GitHub Hardware Repo

FAQs:
Q: What does this sensor measure?
A: The sensor measures both heart rate and blood oxygen saturation (SpO2) levels using photoplethysmography (PPG).
Q: Which chips are used in this sensor?
A: The sensor utilizes two Maxim Integrated chips: the MAX30101 for sensing and the MAX32664 for processing and filtering the data.
Q: Is this sensor compatible with my microcontroller?
A: The sensor is I2C-based and Qwiic-enabled, making it easy to connect to various microcontrollers like Arduino and Raspberry Pi.
Q: What is the accuracy of the heart rate and SpO2 measurements?
A: The MAX32664 provides advanced algorithms and filtering for accurate measurements, but accuracy can vary depending on factors like skin tone, motion, and ambient light.
Q: What applications is this sensor suitable for?
A: This sensor is ideal for wearable health devices, fitness trackers, medical monitoring devices, and other projects that require heart rate and SpO2 measurements.