The Adafruit SGP40 Air Quality Sensor Breakout is a versatile indoor air quality sensor that measures VOC compounds and hydrogen. It is based on metal-oxide (MOX) technology and includes a microcontroller that handles the heater control, signal reading and I2C interface. This makes it significantly easier to use compared to traditional MOX sensors, since you don’t need to separately manage heating and analog measurement.

The SGP40 is specifically designed to assess indoor VOC levels. It does not provide direct TVOC or eCO₂ values like its predecessor the SGP30, but produces a raw signal which is processed by Sensirion’s algorithm into a VOC index (0–500). This allows monitoring of trends and comparisons, but for more accurate results the sensor should be calibrated with known gas sources. In addition, the sensor supports humidity compensation — when an external humidity sensor value is provided to it via I2C, it can correct measurements for improved accuracy.

On Adafruit’s breakout version the SGP40 is soldered onto a custom STEMMA QT form factor PCB that includes a 3.3V regulator, logic level shifting and STEMMA QT / Qwiic connectors on both sides. This enables solderless connection to a development board or chaining with other I2C devices. All pins are also brought out to a standard header so you can use the sensor in the traditional way with a breadboard. QT cable is not included.

Features:

• VOC and H₂ detection for indoor air quality monitoring
• MOX sensor with integrated microcontroller
• I2C interface, no clock stretching
• VOC index 0–500 using Sensirion’s algorithm
• Humidity compensation support via external RH sensor input
• Compatible with 3.3V and 5V systems
• Arduino libraries available

Package includes:

• 1 × Adafruit SGP40 Air Quality Sensor Breakout

Links:

• Product page