CO2 Sensor Sensirion STC31 – RAKwireless RAK12008

The RAKwireless RAK12008 adds a high-concentration CO2 sensing option to the WisBlock ecosystem using the Sensirion STC31. Unlike typical indoor CO2 sensors, the STC31 is designed for very high CO2 levels, covering 0 to 100 vol% and measuring CO2 based on thermal conductivity. It’s intended for applications where elevated CO2 concentrations must be maintained, controlled, or verified—not general indoor air monitoring.

CO2 concentration data is delivered over I2C, and the module includes a built-in temperature sensor. The stated accuracy is 0.5 vol% + 3% (0–25 vol%) and 1 vol% + 3% (0–100 vol%), supporting dependable readings across the full concentration range. With a compact 10×10 mm size, it’s well suited for constrained mechanical designs and tight sensor compartments.

For fast prototyping, the description mentions tutorials, example code, and a ready-to-use software library, making it easier to build a high-CO2 data acquisition setup. Mechanically, the module mounts into the sensor slot on a WisBlock Base board. To use it, you need at least a WisBlock Base (power/slot) and a WisBlock Core module.

Practical use cases include:

Process monitoring and control: maintain and verify high CO2 setpoints in enclosed systems

Test rigs and lab setups: log and validate CO2 levels across high concentration ranges

Product development: prototype CO2 control loops and high-CO2 sensing integrations via WisBlock