SparkFun CO₂ Humidity and Temperature Sensor - SCD40 (Qwiic)

The SparkFun CO₂ Humidity and Temperature Sensor is a state-of-the-art sensor that provides high-accuracy environmental readings. With the next-generation SCD40 photoacoustic CO₂ sensor, it can detect concentrations from 0 to 40,000 ppm with precision over the 400-2000 ppm range. The SCD40 uses Sensirion's PASens^® photoacoustic measurement system, which combines narrow-band IR light and a microphone within the sensor. Additionally, this sensor includes an integrated temperature and humidity CMos^® sensor to enhance accuracy. The sensor also accepts ambient pressure readings for added precision. The compact design, measuring 2.54cm x 2.54cm, allows easy integration into any Qwiic-based projects.

The SCD40 sensor includes an automatic self-calibration routine that adjusts to its environment over a seven-day period. To achieve the best results, it's recommended to take continuous readings for at least an hour a day of 'fresh air' during the calibration period.

SparkFun has developed an Arduino library to simplify reading the CO₂, humidity, and temperature. It can be easily downloaded through the Arduino Library manager by searching for 'SparkFun SCD4x'.

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, reducing the amount of required PCB space, and polarized connections mean you can’t connect it incorrectly.

The SparkFun SCD4x CO₂ Hookup Guide is available to help you get started with the sensor.

The sensor features an I²C interface and operates on a supply voltage range of 2.4-5.5V, with a typical value of 3.3V. It has a low current consumption, with a maximum of 205mA at 3.3V in normal mode, 18mA typically at 3.3V in normal mode, 3.5mA typically at 3.3V in low power mode, and 0.5mA at 3.3V in single-shot mode. The sensor has a CO₂ output range of 0-40,000ppm, a humidity range of 0-100%RH, and a temperature range of -10°C-60°C.

Documentation for the sensor, including the schematic, Eagle files, board dimensions, hookup guide, datasheet, Qwiic information page, SCD4X Arduino Library, and Github hardware repo, is readily available.