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 above.

The SparkFun Qwiic Connect System is an ecosystem of I²C sensors, actuators, shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong.

• 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)

• Schematic
• Eagle Files
• Board Dimensions
• Hookup Guide
• Datasheet (SCD4X)
• Qwiic Information Page
• SCD4X Arduino Library
• Github Hardware Repo