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Build a Smarter Indoor Air Quality Monitor with the SGP40

The Adafruit SGP40 Air Quality Sensor Breakout - VOC Index - STEMMA QT / Qwiic is a compact digital gas sensor breakout made for indoor air quality monitoring. If you want to track changes in air freshness, detect VOC trends, or build a “digital nose” for your project, this board makes it much easier than working with raw analog gas sensors.

At the heart of the breakout is the Sensirion SGP40, a fully integrated MOX gas sensor with onboard control electronics. Instead of managing a heater and reading analog values yourself, you communicate over I2C and process the sensor data into a useful VOC index for dashboards, warning systems, and environmental logging.

Important: The SGP40 does not directly output TVOC or eCO2 readings like the SGP30. Instead, its raw readings are processed using Sensirion’s algorithm to generate an overall VOC Index from 0 to 500.

Why you'll love it

  • Indoor air quality focused: Great for tracking VOC trends in enclosed spaces
  • Digital I2C interface: Easier to use than raw analog MOX gas sensors
  • VOC index output: Convert sensor data into a more practical air-quality style reading
  • Detects VOCs and H₂: Useful for general indoor air-quality trend monitoring
  • Humidity compensation support: Can improve readings when paired with an external humidity sensor
  • STEMMA QT / Qwiic ready: Fast solderless I2C connections for prototypes and sensor chains
  • 3.3V and 5V friendly: Onboard regulator and level shifting simplify integration

What you can build

This breakout is ideal for room air quality monitors, office or classroom environmental sensors, smart home dashboards, HVAC trend tracking, indoor ventilation monitors, desktop air-quality displays, and data logging projects that watch changes in VOC levels over time.

Starter bundles

Pair it with an Arduino-compatible board, Raspberry Pi, Adafruit Feather, or another I2C-capable controller, plus a STEMMA QT cable for faster setup.

Recommended add-ons

For better compensated readings and a more complete environmental monitor, pair it with a humidity sensor, temperature sensor, OLED display, data logger, or wireless microcontroller board.

Technical specifications

Product Adafruit SGP40 Air Quality Sensor Breakout - VOC Index - STEMMA QT / Qwiic
Main Sensor Sensirion SGP40 multi-pixel MOX gas sensor
Interface I2C digital interface
Target Gases Broad range of VOCs and H₂ for indoor air quality trend monitoring
Output Style Raw sensor reading processed with software into a VOC Index from 0 to 500
Clock Stretching Not required
Humidity Compensation Supported with an external humidity sensor over I2C
Power Compatibility Works with 3.3V and 5V systems using onboard regulator and level shifting
Connectors Dual STEMMA QT / Qwiic-compatible JST SH I2C connectors
Pin Access Pins are also broken out to standard headers
Best Use Indoor air quality monitoring, environmental trend tracking, digital nose projects

Pinout & usage notes

The breakout communicates over I2C, making it easy to use with common development boards and single-board computers. Since it is a digital sensor with onboard control, you do not need to manage the heater or interpret raw analog voltages the way you would with simpler gas sensors.

For best results, treat this as a trend sensor rather than a lab instrument. Like other gas sensors, readings can vary from unit to unit, so calibration against known conditions is recommended if you need tighter comparisons or more repeatable thresholds.

What’s in the box

1 × Adafruit SGP40 Air Quality Sensor Breakout

Note: STEMMA QT cable is not included.

Frequently Asked Questions

Does this measure CO2? Not directly. This board is focused on VOC-based indoor air quality monitoring and does not output true CO2 measurements.
Does it output TVOC and eCO2 like the SGP30? No. The SGP40 is processed into a VOC Index rather than direct TVOC/eCO2 values.
Can I use this with Arduino or Raspberry Pi? Yes. It works over I2C and Adafruit provides software support for Arduino, CircuitPython, and Linux-capable systems like Raspberry Pi.
Do I need a humidity sensor? Not strictly, but adding one allows humidity compensation, which can improve measurement stability.
Is the STEMMA QT cable included? No. The board has STEMMA QT / Qwiic connectors, but the cable is sold separately.

Adafruit SGP40 Air Quality Sensor Breakout - VOC Index - STEMMA QT / Qwiic

Adafruit SGP40 Air Quality Sensor Breakout - VOC Index - STEMMA QT / Qwiic

Low stock: 1 left

Product Code

4829

₱ 1,256.00
₱ 1,256.00
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