Please note: This is a Citizen Science project for demonstration purposes only
The RAK7204 is an indoor environmental monitoring station and can measure changes in temperature, humidity, gas pressure and provide an indoor air quality index.
The gas sensor used in this IoT device is the Bosch Sensortec’s BME688 4-in-1 gas sensor with artificial intelligence (AI) and integrated high-linearity and high-accuracy pressure, humidity, and temperature sensors. It is specially developed for applications where size and low power consumption are critical requirements. The gas sensor can detect volatile organic compounds (VOCs), volatile sulphur compounds (VSCs), and other gases such as ethanol, alcohol, carbon monoxide and hydrogen in the parts per billion (ppb) range.
The ideal location for these sensors are in an indoor situation and so the sensors were located across the City of Port Adelaide Enfield catchment at our Port Adelaide, Parks and Greenacres Libraries. These sensors are on display to the public and mounted on a board and placed on a bookstand.
The graphs below, are an example of real data from air-quality sensors at each library. Over the past months the average temperature is 21C, Humidity at 50% and IAQ Index is below 40.
These sensors are connected to the LoRaWAN Network and data is sent wirelessly using the Australian public class licence radio spectrum on (915Mhz) which is received by LoRaWAN Gateways dotted about Adelaide.
LoRa Devices use a specially encrypted machine code that can be accessed and decrypted over the internet by registered users of The Things Network.
This can then be used by other software applications, in our case, an application called NodeRED to process the data into actions, messages or to store it in a database for later use. The database we are using, in this case, is InFluxDB which can be used by a website application called Grafana to display data in a more human-friendly graph on a website.
The flow diagram below is a quick overview of how data flow from the sensor to a graph on Grafana.