Adafruit SGP41 Multi-Pixel Gas Sensor Breakout - VOC & NOx Index - STEMMA QT / Qwiic

The SGP41 provides two separate digital index values. The VOC Index represents the concentration of volatile organic compounds, while the NOx Index represents nitrogen oxides. Both are output on a relative scale from 1 to 500, allowing for independent tracking of these two major air quality parameters without requiring calibration to absolute units like ppm.

Connect the breakout's VIN pin to the Arduino's 5V output. The onboard 3.3V regulator will step this down to power the sensor safely. For I2C communication, connect the SDA and SCL pins to your Arduino's corresponding I2C pins. The built-in logic level shifting ensures the 3.3V sensor signals are compatible with the 5V Arduino logic. You can also use the STEMMA QT/Qwiic connectors for a solderless connection if your main board supports them.

While the SGP41 can operate without one, using an external humidity and temperature sensor (like Sensirion's SHT4x) is highly recommended. The sensor's internal algorithm uses this environmental data to compensate for the effects of humidity and temperature on the MOX sensor response, significantly improving the accuracy and long-term stability of the VOC and NOx index values.

Adafruit provides comprehensive, open-source libraries for both Arduino and CircuitPython. The 'Adafruit SGP41' library handles all communication, including sending the correct conditioning commands, reading the raw signals, and calculating the standardized index values. Example code is included to get started quickly with reading both VOC and NOx indices.