Stations are boxes containing sensors and IT technologies to monitor and measure specific physical and environmental parameters. They are located in specific points of cities.
During the Cagliari2020 project, three kind of stations have to be realized: fixed stations, mobile stations and aerial stations.
Sensors represent the core of the stations: they are specific devices able to measure a physical quantity and its variations and to sent its corresponding value to a control system.
The characteristics of each station are illustrated below.
Fixed stations work in specific points of the city and allow to constantly measure and monitor all environmental parameters but only in the area where they are located.
Fixed stations are made up with:
– GPS sensor for the location of the station;
– optic sensor for the measurements of the concentration of PM10 and PM2.5 particulate in the air;
– electrochemical sensor for monitoring the gas concentration in the air. In particular, stations measure the concentration (in μg/m³) of carbon monoxide, nitrogen dioxide, sulphur dioxide and ozone;
– sensors for measurements of environmental parameter as temperature, pressure, relative humidity etc…
Stations are also equipped with internal power supply (UPS system) and all the electronic components (including ADC converters) for the conversion of the analog signal acquired by the sensors to a digital signal that can be read by a computer system that stores, processes and communicate the data to an external device such as the cloud.
The stations designed for the Cagliari2020 project have low construction costs: for this reason, the computer equipment provided in each station is based on Raspberry Pi3 modules, real computers that, using Linux work environments, process the data received by sensors through particular scripts based on codes written on Python programming language.
In order to process and store the data on which measurements, monitoring process and forecasts are performed, the data acquired by the stations must be sent to external units on which software and programs for the analysis and study of data are implemented. Therefore, the stations must communicate with servers (and the cloud): this is done through an LTE modem equipped with a SIM. Stations communicate with servers similarly to most modern cell phones do.
Below you can see the results of some test measurements performed by the fixed station. All the measurements show values below the threshold for all the parameters detected.
Mobile stations are designed and built in analogy with fixed stations. They are made up of the same sensors, have the same technical and operational characteristics. Mobile and fixed stations just differ on their size: being designed for installations in different places, they must be practical and easy to transport.
Their size and weight is 37 x 45 x 15 cm and 2.7 kg, respectively.
Due to their versatility, mobile stations detect and send data in different ways and in real time: they can be installed on public transport buses or on suitable cars going around cities.
GPS sensor gives the location of stations and it is possible to monitor, locally, all the environmental parameters as desired.
A great number of mobile stations spread all along the streets of a city allows the creation of a detailed environmental map of the city itself.
Aerial mobile station
The aerial mobile stations are installed on drones. Their task is to measure and monitor environmental parameters at different altitudes with respect to the ground.
In this way it is possibile to obtain a three dimensional environmental map of the city.
At the moment, researchers have realized their design and they are in preparation.