In Smart air control: A strategy based on IOT technology to preserve the quality of the air that we breathe, Part 1 of this blog series, NDIR sensors have been introduced as a promising application of IOT technology to preserve environments by monitoring some parameters of interest, such as the level of CO2 of the air in an open environment. The NDIR sensor basic working principle is the measure of the output voltage of a thermopile, which is correlated with the CO2 concentration (see Figure 1):
The NDIR Gas Sensor working principle (Source: TI Application Report SNAA207)
How is it possible to realize an effective control of the quality of the air through the NDIR sensors?
The sensors could be distributed in a large area, being placed at some detection points, equipped with a GSM transceiver, such as a ZigBee transceiver (see Figure 2); all of the nodes of this distributed net could be connected in a wireless mode through a WSN (Wireless Sensor Network) (see Figure 3).
The Zigbee 2.4 GHz transceiver is compliant with the IEEE 802.15.4 communication standard, the latest released communication protocol for the IOT technology communication network (Source: TI CC2520 Data Sheet)
A WSN network (Source: MDPI article)
The nodes of the WSN net communicate with each other by utilizing some integrated wireless modules; moreover, this net of distributed wireless CO2 sensors is able to communicate with a central hub. The air environment CO2 concentration data could be elaborated and stored in a surveillance control center that might monitor and record the levels. This record track could be utilized to figure out the CO2 concentration levels on different days for a specific point of interest; thus preserving the environment and the population in case of detection of high levels of this gas for a specified timeframe threshold.
It’s been demonstrated that the exposure to high levels of CO2 concentration for a specific time interval might be dangerous for human health. This control could be very important to alert, in real time, the workers of a factory production environment in case of CO2 dangerous concentration values detected in the work environment. This type of control has been implemented by the ENEA in the Mount Sinni, Sardegna, Italy, to monitor and track the levels of CO2 in an underground site previously utilized by carbon manufacturing industries. The project of monitoring the potential CO2 gas leakages was successful and it’s been realized through a WSN network of NDIR sensors distributed in a large area (see Figure 4):
What do you think of WSN networks composed of NDIR sensors? Is this a feasible solution to monitor the quality of the air of a large town?