This SparkFun CO2 Humidity and Temperature Sensor features the next-generation SCD40 photoacoustic CO2 sensor for high-accuracy environmental readings. The SCD40 uses Sensirion's PASens® photoacoustic measurement system that combines narrow-band IR light and a microphone inside the sensing package capable of detecting concentrations from 0 to 40000 ppm with high accuracy over 400-2000 ppm ±(50 ppm+5%). The SCD40 has an integrated temperature and humidity CMos® sensor to improve accuracy. For additional accuracy, the SCD40 also accepts ambient pressure readings! All this functionality comes in our standard 1in. x 1in. Qwiic form factor and will seamlessly integrate into your Qwiic-based projects. However, we still routed the I2C signals out to a set of 0.1in.-spaced pins for users who prefer a soldered connection. The SCD40 includes an automatic self-calibration routine to automatically adjust to its sensing environment over a seven-day calibration period. For best results, Sensirion recommends taking continuous readings for at least one hour a day of 'fresh air' for the calibration period to complete. We've written an Arduino library to make reading the CO₂, humidity, and temperature very easy. It can be downloaded through the Arduino Library manager: search for 'SparkFun SCD4x', or it can be found in the Documents tab below. Get started with the Sparkfun SCD4X CO2 hookup guide Features * I2C Interface (Qwiic-enabled) * I2C Address: 0x62 * 2x Qwiic Connectors * Supply Voltage Range: 2.4-5.5V (3.3V Typ.) * Low Current Consumption: * Normal Mode: * Max: 205mA@3.3V * Typ: 18mA@3.3V * Low Power Mode: * Typ: 3.5mA@3.3V * Single-Shot: * 0.5mA@3.3V * Photoacoustic Measurement System * Sensirion's PASens Technology * Integrated Temperature and Humidity Sensor * Sensirion's CMOSens Technology * CO2 Output Range: 0-40,000ppm * CO2 Measurement Accuracy: ±(50ppm + 5% of reading) * Conditions: 400-2,000ppm * Humidity Range: 0-100%RH * Humidity Accuracy: ±9%RH (Full Range) * Temperature Range: -10°C-60°C * Temperature Accuracy: ±1.5 (Full Range) Resources * Schematic * Eagle Files * Board Dimensions * Hookup Guide * Datasheet (SCD4X) * Qwiic Information Page * SCD4X Arduino Library * Github Hardware Repo https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2023-07-08 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2023-12-27 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2024-09-18 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2024-11-29 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2024-11-30 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-04-10 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-04-29 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-08-05 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-09-29 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-11-28 https://elecena.pl/product/23750123/sparkfun-co-humidity-and-temperature-sensor-scd40-qwiic 2025-11-29