Story: Smart city have smarter transport system, halls, shops, vehicles, buildings, parks, etc. It is necessary to be free from pollutants in the smart city in order to check the environmental conditions of the city it is better to have smart device to sense the parameters which can be helpful to the meteorologists and forecaster about the current health state of the city.
In the present project we are going to use SensorTile to monitor the environmental parameters like temperature, pressure, humidity, wind speed, direction using on-board temperature sensor, pressure sensor, humidity sensor, accelerometer, gyro, magnetometer. The following steps explain how we construct Bolloonsonde and used for environmental conditions monitoring.
Step 1: We have weather stations located at important and safety sites to monitor environmental conditions like temperature, pressure, humidity, wind speed, direction, sun radiation, rainfall. This helps to measure the conditions over a particular site and useful only for that area. For a city we need to place multiple stations network to analysis and find the city conditions. This weather station is fixed at location and upto 5m height level.
Step 2: In order to replace the fixed weather station we have used SensorTile as mobile weather station using Hydrogen filled balloons. Hydrogen gas is filled in balloon to lift the SensorTile up to 25 meters height because the range of Bluetooth is within this limit to record data in mobile app. The sensortile device is attached to balloons using kite thread, we use this as kite because the SensorTile can be lifted into space due to hydrogen filled balloon we may loss the device.
Step 3: Once the Balloonsonde is ready we switch ON the SensorTile device to connect the mobile app.
Step 4: The app is started to scan for checking the device availability.
Step 5: Once the device is identified we can establish a connection by clicking on the device from the list.
Step 6: The app open the status of the measuring sensors at initial screen. Click on the START LOGGING to log the data from sensors and store in the SD card.
Step 7: We can see the temperature recording on the app screen the graph shows how the temperature is going to change with respect to time. The sensor is still at ground level and not lifted to the required level (E.g. 5m, 10m, 15m, 20m, 25m).
Step 8: We can visualize the pressure data in the app by selecting the pressure option from the selection list.
Step 9: Slowly now lift the balloons to 5 meter height level by releasing the thread. The measurement can be carried out for the specified time foe example 5 minutes, one hour or a day as upon the user wish.
Step 10: Now the balloonsonde is lifted to a height of 10 meters to record the data over that height
Step 11: Pressure sensor record a slight change in pressure with change in altitude and the environmental conditions.
Step 12: The magnetometer shows the sensor movement in different direction due to wind direction. In calm wind the deflection is minimum, due to wind flow it shows change in direction.
Step 13: The Balloonsonde is lifted to the height of 15 meters to record data over that height.
Step 14: The magnetometer shows their are slide change in winds over that height.
Step 15: The balloonsonde is now lifted to 20 meters height.
Step 16: Balloonsonde is lifted to the maximum height to record data at that particular height.
Step 17: The data of wind speed is found from magnetometer their are some what high winds when compared to the ground level.
Step 18: Accelerometer sensor from SensorTile also confirm the wind speed and direction variations.
Step 19: The recorded data can be saved in SD card and transfer to meteorologists to have a detail analysis on the city environmental conditions.
Step 20: The recorded data is used to plot the profile from ground level to 25 meters height level. The temperature data plot is shown in the below figure.
Step 21: Humidity profile shown in the figure over the site in our campus.
Step 22: Pressure profile as move up in the sky the pressure is going to change which can be seen from this plot.
Step 23: Wind direction changing as the sensortile is fluctuated with the balloon lift. but gives about direction information.
Step 24: Finally the wind speed profile give the change in wind speed as we lift the sensor device from ground level to 25 meters.
Video shows how we measure environmental conditions using the SensorTile and Hydrogen filled balloons as a Balloonsonde.
Conclusion: The measurement are carried out at different heights using the SensorTile device. The maximum measurable height is about 25 meters from ground level we cannot go beyond due to the Bluetooth limitations. This balloonsonde is useful to the meteorologists to analysis the environment over a city and can also helpful for farmer in their crop when to using pesticides spraying. With the automated weather station this kind of feasibility is not available because it is fixed to site and height. With the environment measurement over a city we can estimate the air pollution by temperature observation and can estimate the spreading using wind data. SensorTile is useful to make our city clean and smarter.