An IoT Monitoring System for the Accurate Measurement of CO2 Concentration Due to Plants Photosynthesis

The estimation of the CO2 concentration variations due to plants photosynthesis has become a topic of outstanding interest in view of evaluating the carbon footprint of greenhouses and farms. In this context, distributed sensing solutions can be an alternative to expensive gas analyzers. However, gas sensing can be prone to several criticalities linked to accuracy, stability, and temperature effect. In this paper, a thorough study for the conditioning, the calibration, and the acquisition of an optical sensor for CO2 monitoring is presented. The sensor is integrated in a node thought for greenhouse monitoring and the whole system is tested during measurement campaigns in free air and in a closed chamber housing some plants. The results of calibration and tests prove that the device can detect the CO2 variation due to plants photosynthesis with a resolution of 10 ppm and satisfactory measurement accuracy, paving the way for $\text{CO}_{2}$ fluxes monitoring even with low-cost and low-power embedded solutions.