Heart Rate Measurement Module

The Arduino Heart Rate Measurement Module is a practical and easy-to-use optical pulse sensor that allows you to measure a person's heart rate (pulse) in beats per minute (BPM) using just a fingertip. The sensor works on the principle of photoplethysmography (PPG) — by using an infrared LED transmitter to shine light through the fingertip and an infrared receiver on the opposite side to measure how much light passes through. With each heartbeat, blood pulses through the capillaries in the fingertip , momentarily changing the amount of light absorbed by the tissue. The IR receiver detects these subtle variations and the onboard amplifier circuit converts them into clean electrical signals. The result is a pulsing waveform that directly corresponds to the user's heartbeat — making it perfect for measuring heart rate, detecting rhythm patterns, and visualizing cardiac activity . The module provides two outputs simultaneously : AO (Analog Output): A continuous analog waveform that mirrors the actual pulse signal. When viewed on an oscilloscope or read with a microcontroller's ADC, you can clearly see the heartbeat waveform, perform peak detection, and calculate BPM in software. DO (Digital Output): A clean digital pulse signal that goes HIGH or LOW with each detected heartbeat, allowing you to count beats directly with a microcontroller's digital input pin — no analog reading required. The output amplitude is adjustable , allowing you to tune the signal up to approximately one-third of VCC for optimal compatibility with different microcontrollers. The module operates on a wide voltage range of 3.3V to 5V , making it directly compatible with Arduino UNO, Nano, Mega, ESP32, ESP8266, STM32, and Raspberry Pi . Designed with high-quality 0805 SMD resistors and capacitors , the module offers stable, repeatable performance suitable for both educational experiments and serious hobby projects . The finger-clip form factor holds the fingertip in place between the IR emitter and receiver for stable, motion-resistant readings. Whether you are building a DIY fitness tracker, a heart rate monitor display, a biofeedback meditation app, an emergency health alert system, or an educational biomedical project , this heart rate sensor module gives you reliable pulse data with minimal effort. Important Note: This module is intended for hobby, educational, and DIY use only — it is not a certified medical device and should not be used for clinical diagnostic purposes. Specifications General Sensor Type: Optical Heart Rate (Pulse) Sensor — IR Transmission Method Form Factor: Finger-clip design for stable fingertip measurement Sensing Principle: Photoplethysmography (PPG) via IR LED + IR receiver Power Input Voltage: 3.3V – 5V DC Component Quality: Built with 0805 SMD resistors and capacitors Outputs AO (Analog Output): Continuous analog waveform of the pulse signal DO (Digital Output): Digital pulse signal (HIGH/LOW with each heartbeat) Output Amplitude: Adjustable up to approximately 1/3 of VCC Compatibility Arduino UNO, Nano, Mega ESP32, ESP8266 STM32, PIC Raspberry Pi (via ADC) Any microcontroller with digital and/or analog input Documentation Schematic provided for advanced users and developers Applications DIY heart rate monitors with LCD or OLED display Fitness and exercise tracking devices for hobbyist wearables Biofeedback and meditation aids that respond to heart rate Stress monitoring projects combined with GSR or temperature sensors Emergency alert systems that detect abnormal pulse patterns Sleep monitoring devices measuring resting heart rate over time Educational STEM projects teaching biomedical signals and microcontrollers University and lab biomedical experiments for student research Smart wristbands and watches for hobby and prototyping use IoT health dashboards uploading pulse data to cloud platforms Game controllers that adapt difficulty based on player heart rate Music and art installations that respond to participants' vital signs Wearable wellness devices tracking calm, focus, and recovery Telemedicine prototypes for student and research projects Polygraph-style multi-sensor projects combined with GSR and respiration sensors Sports performance training tools for personal use Heart rate–driven LED displays and visualizations Reaction time and stress experiments in psychology research Smart home environments that adjust ambiance based on user state Pet and animal monitoring prototypes for hobbyist applications