{"title":"Adafruit SGP40 Air Quality Sensor Breakout - VOC Index - STEMMA QT / Qwiic","handle":"adafruit-sgp40-air-quality-sensor-breakout-voc-index-stemma-qt-qwiic","url":"/products/adafruit-sgp40-air-quality-sensor-breakout-voc-index-stemma-qt-qwiic","description":"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.\n\nThe 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.\n\nKey Features\n\n\nVOC Index Output – Processed air quality score from 0 to 500 via Sensirion's algorithm\n\nWide VOC Detection – Detects a broad range of volatile organic compounds and H2\n\nHumidity Compensation – Accept external humidity data over I2C for improved accuracy\n\nI2C Interface – No clock stretching required; STEMMA QT / Qwiic connectors for solderless hookup\n\n3.3 V / 5 V Compatible – Onboard 3.3 V regulator and level shifting\n\nNext Generation – Successor to the SGP30 with improved sensing architecture\n\n\n\nNote: The SGP40 does not output TVOC or eCO2 values like the SGP30. Instead, it provides a VOC index (0–500) processed through Sensirion's algorithm. Like all VOC/gas sensors, calibration against known sources is recommended for precise measurements. Arduino library available; Python support is not yet available.\n\n\nAlso Consider\n\n\nSGP30 Air Quality Sensor – Previous generation with direct TVOC and eCO2 output values\n\nSCD-40 True CO2 Sensor – Direct photoacoustic CO2 measurement (400–2,000 ppm)\n\n\nIdeal For\n\nIndoor air quality monitoring and trend detection\nSmart ventilation triggering\nEnvironmental sensing projects\nVOC detection in homes and offices\n\n\nPackage Contents\n\n1× Adafruit SGP40 Air Quality Sensor Breakout\n\n\n\nTip: STEMMA QT / Qwiic cable is not included. Pair with an external humidity sensor (like the SHT40 or SHT45) for humidity-compensated readings and improved accuracy.\n\n\nResources\n\nArduino Library (GitHub)\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":3609,"title":"Default Title","sku":"AF-4829","price":30.03,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":3,"option1":"Default Title"}]}