In this example, the interaction with IOT Devices counting people by using Wi-Fi and Bluetooth sniffing in its vicinity according to GDPR [GDPR], is presented.
In Figure 12, a mobile PAXCounter based on ESP32 sending messages to Snap4City via LoraWAN. see https://www.snap4city.org/drupal/node/456
Other simpler versions can be located on fixed places, and may also use WiFi to send the obtained measures including additional sensors. In the presented example, they have been used to monitor a Museum in Antwerp and many other locations. A total of 22 devices have been installed. The measured values are sent to LoraWan operator The Things Network, which does not provide a system for data analysis but only to receive and manage devices.
Figure 12: A mobile PAX counter based on ESP32.
Museum Case
Considering the example of the museum, one could be interested in monitoring the flow of entering and exiting visitors, having a history of such data and not only the realtime value. To this end, the data has to be saved permanently into time series data store, for example into MyKPI, MyPOI storage via MicroServices. This approach of Snap4City allows at the IOT Developers to create and retrieve data entities trends directly in Dashboard and for Data Analytics, as data Shadow. According to this solution, an IOT App has been created for PaxCounter to receive in Event Driven mode the new coming from The Things Network (as IOT Gateway), according to the Publish Subscribe model of MQTT, and they are saved MyKPI via MicroServices. Thus, Dashboard Wizard automatically sees the data entity on the MyKPI and allowed us to automatically create Widgets showing their trends, realtime values, etc. In Figure 13, the Dashboard presenting the time trends of the entrances and exists of the museum and derived data. All the derived values of the initial real time data can be computed in real time, saved on personal storage and shown on dashboard via the IOT Application exploiting MicroServices of Snap4City. At the same time as calculating the sums, the difference between the people entering the museum and those leaving to obtain the number of people inside the museum in another entity is also made.
Figure 13: Monitoring MAS Museum people flows.
Through the Dashboard widget and IOT App, it is possible to send commands to the PaxCounter via the IOT Gateway get the status of the device as well as to change the settings. A command that can be useful in the case of PaxCounter installed in the museum can be the one that changes the mode of counting people from cyclic to cumulative. In the cyclic mode every 8 minutes the count is reset and with it the anonymous data of the devices counted by the PaxCounter are deleted: in the next 8 minutes if a person stands near the Pax Counter is counted again. In cumulative mode the count is not reset but is increased with the new people who arrive near the Pax Counter and the duplicate count of the same person is avoided until the device is in cumulative mode.
Mobile PaxCounter for monitoring events
The mobile PAXCounter presented in Figure 12 has been used for monitoring events, sports as well as of entertainment in general. Each new measured counting is associated with a GPS coordinates and sent to the platform thus resulting in trajectories with associated values as depicted in Figure 14, exploiting the Widget tracker of Snap4City.
Figure 14: Tracking PAX Counters, measures over time and space.
Also in this cases, it could be very important to change modality for passing from Cyclic to Cumulative counting. To this end, in order to program the change of modality an IOT Applications with a dedicated Dashboard user interface has been realized as reported in Figure 15.
Figure 15: Management of the Mobile PAXCounter with the possibility of programming change of modality.
In this case, the IOT Application is more complex since it needs to (i) collect data, (ii) program the IOT devices, (iii) interact with the user to collect the data for programming, (iv) monitoring the status of the IOT device to verify if the setting has been successfully applied, (v) reporting the status of the IOT device to the user. All these functionalities have been implemented in a single IOT App as reported in Figure 16.
Figure 16: IOT App controlling mobile PAXCounter
In this case, also a custom widget has been developed to allows defining the begin and the end of the programmed period of cumulative mode. The activation of the programmed interval is performed by pressing the "Activate" button that saves the times within the IOT App. It is the IOT App that performs change of modality change at the due time since the IOT Devices are not programmable. In addition, 3 Single Content widgets to display the activated period of cumulative mode, the status of IOT App for setting data to the device, and the state of the IOT Device.In Snap4City, Custom widgets can be developed by creating them in SVG and implementing a specific process for connecting them to MyKPI of Snap4City.
Once the custom widget has been created, the IOT App has been created realizing the control logic covering all the functionalities listed above by exploiting the MicroServices for: dashboard widget, exploiting personal storage, connecting with IOT Gateway, etc.
From the point of view of the life cycle, the above presented IOT Applications can be saved into the Resources Manager, thus allowing to other users to download and install in their own resource area and use them, with their own devices.
