SparkFun Pulse Oximeter and Heart Rate Monitor Hookup Guide
Elias The Sparkiest 
Hardware Overview
Power
You can provide 3.3V through the Qwiic connector on the "MAX32664 Side" of the board or through the 3V3 and GND labeled pins on the through hole header.
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| MAX30101 Side | MAX32664 Side |
Qwiic Connector or I2C Pins
There are two Qwiic connectors on the board to easily get data from the sensor via I²C. Another option is to solder directly to the I²C plated through holes on the side of the board. Unfortunately, this board requires additional pins to function, see section below Additional Required pins.
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| MAX30101 Side | MAX32664 Side |
We have many Qwiic sensors and Qwiic enabled microcontrollers. Check out our Qwiic Ecosystem page to get a glimpse of what else we have to offer.
Additional Required Pins
This board has two additional pins on it's header: the RESET and MFIO pin. These pins are required for the board to function because they determine if the board enters data collection mode or not. The Hardware Hookup section below will walk you through how to connect this board properly.
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| MAX30101 Side | MAX32664 Side |
MAX30101 - Pulse Oximeter and Heart Rate Monitor
The MAX30101 gets your heart rate (BPM) and blood oxygen levels (SpO2) through the process of photoplethysmography, which is the process of obtaining the aforementioned biometric data with light. The SparkFun Pulse Oximeter works by placing your finger gently on the sensor in which it shines red, infrared, and sometimes green light through your skin. The capillaries filled with blood under your skin will absorb this light, or not, and the MAX30101 sensor will read which light comes back. This light data will then be sent back to the Biometric Sensor Hub which handles all the calculations to determine heart rate and blood oxygen levels. Simple right?!
MAX32664 - Biometric Sensor Hub
The MAX32664 Biometric Sensor Hub is a very small Cortex M4 micro-controller dedicated to receiving the data it receives from the MAX30101 and running the calculations to determine heart rate and blood oxygen. When you're interfacing with the SparkFun Pulse Oximteter and Heart Rate Monitor, you are in effect interfacing with this wicked fast microcontroller. There are a multitude of settings to tailor the sensor to the persons you'll be monitoring made available through the Arduino Library we've written for it. Check the Arduino Examples below for more info!
Jumpers
There a single set of jumpers on the MAX30101 side (non Qwiic connector side) of this product. This triple jumper labeled I2C connects pull-up resistors to the I²C data lines. If you're daisy chaining many I²C devices together, you may need to consider cutting these traces.
Dimensions
This board is very small, measuring at 1.00in x 0.5in (25.4mm x 12.7mm), which means it will fit nicely on your finger without all the bulk.
