Adafruit SCD-40 CO2 SENSOR STEMMA QT

Adafruit SCD-40 is a photoacoustic "true" CO₂ sensor that measures the actual carbon dioxide concentration in parts-per-million. Unlike VOC-based sensors, it provides direct CO₂ readings, making it highly suitable for air quality monitoring, environmental studies, scientific research, and ventilation analysis.

The SCD-40 measures in the range of 400–2000 ppm with an accuracy of ±(50 ppm + 5% of reading). It communicates over I2C, and both Arduino and CircuitPython/Python libraries are available for easy integration. Compared to the larger SCD-30, the SCD-40 is smaller in size while maintaining similar measurement performance.

The breakout board features STEMMA QT connectors, compatible with SparkFun Qwiic, enabling solder-free connections and easy daisy-chaining with other I2C devices. An onboard 3.3V regulator and level shifting circuitry allow safe operation with both 3.3V and 5V logic systems.

Specifications

• Measurement range: 400–2000 ppm CO₂
• Accuracy: ±(50 ppm + 5% of reading)
• Interface: I2C, STEMMA QT / Qwiic compatible
• Operating voltage: 3.3–5 V
• Onboard 3.3V regulator and level shifting
• Compact size

Package includes

• 1 × Adafruit SCD-40 breakout (assembled and tested)
• Header strip

Links

• Product page