{"title":"Adafruit SCD-40 - True CO2, Temperature and Humidity Sensor","handle":"adafruit-scd-40-true-co2-temperature-and-humidity-sensor","url":"/products/adafruit-scd-40-true-co2-temperature-and-humidity-sensor","description":"The Adafruit SCD-40 is a photoacoustic true CO2 sensor that directly measures carbon dioxide concentration in ambient air, rather than estimating it from volatile organic compounds. It also includes integrated temperature and humidity sensing, providing comprehensive environmental data from a compact module.\n\nCompared to the larger NDIR-based SCD-30, the SCD-40 uses a different measurement technique that allows a much smaller form factor while delivering similar data quality. Data is read over I2C with Arduino and CircuitPython libraries available for quick setup.\n\nKey Features\n\n\nTrue CO2 Measurement – Photoacoustic sensing, not VOC-based estimation\n\nMeasurement Range – 400 to 2,000 ppm CO2\n\nAccuracy – ±(50 ppm + 5% of reading)\n\nIntegrated Temperature & Humidity – Built-in environmental sensors for compensation and standalone readings\n\nI2C Interface – STEMMA QT / Qwiic connectors for solderless hookup and daisy-chaining\n\n3.3 V / 5 V Compatible – Onboard 3.3 V regulator provides clean, low-ripple power for accurate readings; level shifters for 5 V logic\n\nCompact Form Factor – Significantly smaller than NDIR-based CO2 sensors\n\n\n\nTip: The SCD-40 (400–2,000 ppm) is optimised for indoor/outdoor air quality monitoring. For industrial or scientific applications requiring wider range (400–5,000 ppm) and better accuracy, consider the SCD-41.\n\n\nAlso Consider\n\n\nSCD-30 NDIR CO2 Sensor – Larger NDIR-based sensor with 400–10,000 ppm range and ±(30 ppm + 3%) accuracy\n\n\nIdeal For\n\nIndoor air quality monitoring and ventilation studies\nSmart building and HVAC systems\nClassroom and office CO2 monitoring\nEnvironmental sensing and scientific experiments\n\n\nPackage Contents\n\n1× Adafruit SCD-40 True CO2, Temperature & Humidity Sensor Breakout\n\n\n\nNote: STEMMA QT / Qwiic cable is not included. Use a compatible JST SH cable for solderless connection, or solder directly to the header pads.\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":2938,"title":"Default Title","sku":"AF-5187","price":91.16,"on_sale":false,"in_stock":true,"available_quantity":100,"option1":"Default Title"}]}