Overview
Atmotube PRO 2 features a Sensirion STCC4 miniature CO2 sensor, based on thermal conductivity measurement.
This technology detects changes in gas composition compared to fresh air and calculates CO2 concentration automatically.
The sensor is factory-calibrated and provides humidity and temperature compensation through the integrated SHT4x sensor.
Typical accuracy is ±(100 ppm + 10 % of reading) between 400 ppm and 5000 ppm.
Recommended Operating Conditions
Temperature: 10 – 40 °C
Humidity: 20 – 80 % RH (non-condensing)
Warm-up time: up to 1 hour after long idle or power-off (> 3 h)
Best Practices for Reliable CO2 Measurements
Let the sensor stabilize
After first activation or long storage, let the device run in continuous measurement mode for at least 12 hours in a ventilated area (fresh air ≈ 400 ppm CO2).
This stabilizes the internal Automatic Self-Calibration (ASC) algorithm.
Ensure Regular Exposure to Fresh Air
The self-calibration assumes that the device experiences air around 400 ppm CO2 at least once per week. If the device operates continuously in high-CO2 environments (e.g., indoor labs, offices), its readings may drift upward over time.
Avoid Artificial Gas Mixtures
Do not test the sensor in pure nitrogen, oxygen, or other artificial gas blends.
These gases have different thermal conductivity from normal air and can produce inaccurate results.
Operation After Long Pauses
If the device has been unused or powered off for more than 3 hours, start it and allow at least 1 hour of continuous operation for the sensor to re-stabilize.
Use Forced Recalibration When Necessary
In controlled environments where reference CO2 levels are known (e.g., 400 ppm outdoors), you can run a Forced Recalibration (FRC) to align readings precisely.
