The KY-039 Finger Detection Heartbeat Measuring Sensor Module is a basic optical pulse sensor designed to detect heartbeats using the photoplethysmography (PPG) method. It uses an infrared LED and a phototransistor to sense blood flow changes in the fingertip, producing an analog signal that can be processed by a microcontroller. This module is widely used in Arduino health monitoring projects, educational experiments, and DIY pulse rate detection applications.
Core Sensor Specifications
• Sensor Type: Optical heartbeat / pulse detection sensor
• Module Model: KY-039
• Detection Method: PPG (photoplethysmography)
• Measurement Output: Pulse waveform signal
Electrical & Interface
• Operating Voltage: 3.3 V – 5 V DC
• Output Type: Analog signal
• Interface Pins: VCC, GND, SIGNAL
• Sensor Elements: IR LED + phototransistor
• Signal Requirement: Filtering and amplification in software/hardware
Performance Characteristics
• Detects pulse changes from fingertip blood flow
• Works best with steady finger placement
• Output waveform can be used to calculate BPM
• Suitable for basic heartbeat detection experiments
Physical Characteristics
• Module Type: PCB-mounted pulse sensor
• Form Factor: Compact with fingertip sensing area
• Lightweight and easy to mount
• Best used in controlled indoor light conditions
Compatibility
• Arduino Uno / Nano / Mega
• ESP8266 / ESP32 (ADC range matching required)
• Raspberry Pi (with external ADC)
• DIY health monitoring circuits
• Educational biomedical projects
Key Advantages
• Simple and low-cost pulse detection module
• Easy to interface with ADC input
• Ideal for learning PPG heart rate measurement
• Compact and beginner-friendly design
Technical Insights
• Sensitive to ambient light and finger movement
• Requires signal filtering for stable BPM
• Not a medical-grade heart rate monitor
• Best results with consistent pressure on sensor
Applications
• DIY heart rate monitoring projects
• Arduino biomedical experiments
• Pulse waveform visualization
• STEM learning and training kits
• Educational health electronics projects
Pro Tip
• Use black tape around sensor to block ambient light
• Apply gentle pressure (avoid squeezing too hard)
• Use averaging and peak detection in code
• Keep finger steady for accurate readings
Package Includes
• 1 × KY-039 Finger Detection Heartbeat Measuring Sensor Module