The Adafruit SGP40 is a next-generation MOX (metal-oxide) gas sensor from Sensirion for indoor air quality monitoring. Unlike its predecessor the SGP30, the SGP40 outputs a raw signal that is processed through Sensirion's VOC algorithm to produce an overall air quality index from 0 to 500 — rather than separate TVOC and eCO2 values.

The sensor combines multiple metal-oxide sensing and heating elements on a single chip with a built-in microcontroller that manages the heater, reads analog voltages, and provides an I2C interface. No I2C clock stretching is required.

Key Features

• VOC Index Output – Processed air quality score from 0 to 500 via Sensirion's algorithm
• Wide VOC Detection – Detects a broad range of volatile organic compounds and H2
• Humidity Compensation – Accept external humidity data over I2C for improved accuracy
• I2C Interface – No clock stretching required; STEMMA QT / Qwiic connectors for solderless hookup
• 3.3 V / 5 V Compatible – Onboard 3.3 V regulator and level shifting
• Next Generation – Successor to the SGP30 with improved sensing architecture

Also Consider

• SGP30 Air Quality Sensor – Previous generation with direct TVOC and eCO2 output values
• SCD-40 True CO2 Sensor – Direct photoacoustic CO2 measurement (400–2,000 ppm)

Ideal For

• Indoor air quality monitoring and trend detection
• Smart ventilation triggering
• Environmental sensing projects
• VOC detection in homes and offices

Package Contents

• 1× Adafruit SGP40 Air Quality Sensor Breakout

Resources

• Arduino Library (GitHub)