MAX30102 Pulse Oximeter Heart Rate Sensor Module

🔍 What this module is
The MAX30102 is a biometric sensor used to measure:
❤️ Heart Rate (BPM)
🩸 Blood Oxygen Saturation (SpO₂)
It uses optical sensing (PPG – Photoplethysmography), shining light into your skin and measuring reflected signals.
⚙️ Key Specifications
Sensor type: Optical pulse oximeter (Red + IR LEDs)
Measurements: Heart rate + SpO₂
Interface: I²C (up to 400 kHz)
Operating voltage: 3.3V–5V (module), core ~1.8V
ADC resolution: up to 18-bit
Current consumption: ~600µA–1.2mA (active)
Shutdown current: ~0.7µA (very low power)
🧠 Key Features
✔️ Integrated LEDs + photodiode + ADC
✔️ High accuracy with ambient light cancellation
✔️ FIFO buffer (reduces MCU load)
✔️ Motion artifact reduction (better readings)
✔️ Ultra-low power → ideal for wearables
✔️ Built-in temperature sensor (for calibration)
🔌 Pinout (Typical)
VIN / VCC → 3.3V or 5V
GND → Ground
SDA → I2C Data
SCL → I2C Clock
INT → Interrupt (optional)
👉 I2C address: usually 0x57
⚡ Working Principle (simple)
Red (660nm) & IR (880nm) light pass through your finger
Blood absorbs light differently based on oxygen level
Sensor calculates SpO₂ + pulse rate from variations
💡 Applications
Smartwatches / fitness bands
DIY pulse oximeters
Health monitoring systems
IoT healthcare projects
Biomedical research
⚠️ Important Notes (very important)
⚠️ Finger placement matters a lot (stable contact needed)
⚠️ Not medical-grade accuracy (DIY use)
⚠️ Needs filtering + algorithm for correct BPM/SpO₂
⚠️ LEDs won’t glow unless initialized in code (common beginner issue)
👉 Many beginners think the sensor is faulty when LED doesn’t turn on—actually you must configure registers in code first (very common issue in practice).
🆚 MAX30102 vs MAX30100
Feature
MAX30100
MAX30102
Accuracy
Lower
Higher
Noise handling
Basic
Improved
Power consumption
Higher
Lower
Stability
Moderate
Better
👍 When to use this
Use MAX30102 if you want:
Accurate heart rate sensing
SpO₂ monitoring projects
Wearable / IoT healthcare systems