DFRobot Gravity Heart Rate Monitor Sensor for Arduino - PPG Optical Sensor Module

The module accepts a wide input voltage range from 3.3V to 6V DC. A 5V supply is recommended for optimal performance and compatibility with standard Arduino boards. When connecting to 3.3V logic systems like Raspberry Pi or ESP32, you can power it directly from the 3.3V pin.

Use the 3-pin Gravity cable (included) to connect the module's Signal (S), VCC (+), and GND (-) pins to your Arduino. The Signal pin can be connected to an analog input (e.g., A0) for waveform reading or a digital input for pulse counting. For easiest setup, use a DFRobot Gravity I/O Expansion Shield for plug-and-play operation.

Yes. For Raspberry Pi or other 3.3V logic platforms, power the module from the 3.3V pin. The analog output can be read using an external ADC (MCP3008, ADS1115) since the Pi lacks built-in analog inputs. The digital pulse output can be connected directly to a GPIO pin for counting.

For reliable PPG signal acquisition, place the sensor on a vascularized area with minimal tissue between the skin and capillaries. Common effective locations include the fingertip, wrist (radial artery side), earlobe, or temple. Ensure firm but comfortable contact and shield the sensor from ambient light for best results.

The analog output provides a continuous voltage (0-Vin) proportional to the detected blood flow, allowing you to plot the full PPG waveform and extract heart rate variability (HRV). The digital output is a clean, squared pulse (0V/Vin) synchronized with each heartbeat, ideal for simple pulse counting and instantaneous heart rate (BPM) calculation.