## 4 Implementation and Testbed  
This section presents the proposed solution as deployed and validated in a farmhouse that covered a large set of different agricultural activities using flying IoT. The low-cost proposal platform was considered for comprehensive monitoring of environmental parameters using both under- and aboveground sensors. Field experiments were carried out from March 2020 to March 2021 at Medenne, Tunisia; some background information about this region, such as geographic location, soil property, and climate can be referred to the map of world climates.  
The proposed system can be explained in five steps, as Figure 9 shows. S-THB-M008 refers to temperature/humidity sensor, S-RGB-M002 refers to rain gauge sensor, S-LIB-M003 refers to solar radiation sensor, and S-SMC-M005 refers to soil moisture smart sensor. First, both under- and aboveground sensors collected relevant data from the farm every 1 h. Second, these data were stored temporarily on an embedded Secure Digital (SD) card in the wireless server gateway. Third, the drone flew and collected data from various wireless server gateways located in the farm every 12 h. Fourth, the drone sent the data to the cloud. Fifth, automated and human-made sets of actions could be taken to apply smart actions for precision agriculture, which, in turn, dramatically boost crop productivity, and help in saving natural resources. These actions could be obtained from the cloud into the user interface smart device. However, a decision support system could be introduced in a future study to link the farm's smart devices together to achieve an autonomous system.  
Figure 10 shows the sensor placement that was considered in our practical experiments. In total, there were 4 HOBO U30 Weather Station Kits deployed in the field in various experimental parcels from our farm. Each Station Kit had one temperature/humidity sensor (Ref: S-THB-M008), one rain sensor (Ref: S-RGB-M002), two soil moisture sensors (S-SMC-M005), and one solar radiation sensor (S-LIB-M003). This layout of the farm was divided into four sections according to its current layout, where each HOBO Weather Station Kit was placed in every section with a distance of about 0.5 km between each other. Each HOBO Weather Station was powered with renewable energy from the sun via solar panels, while smart sensors to measure temperature/humidity, rain, and solar radiation were linked to this kit. This means the lifetime of these sensors are very long and sufficient, due to rechargeable battery using solar panels.  
For UAV setup, the DJI Quadcopter drone was used for the testing scenario. All hardware modules for the sender were mounted on the drone including, the LoRa transceiver. The considered drone was a fixed-wing type, which enabled coverage of large geographic areas with low energy consumption. For the sake of improving energy utilization efficiency, the flight path of the drone was planned previously using Strip's approach, as Figure 11 demonstrates, using freeware Mission Planner software calibrated by remote control [40]. The considered drone was equipped with a rechargeable battery with a flight time of about 30 min, where the drone fle every 12 h to collect data from four server ground gateways that linked to HOBO, before transmitting it to the cloud for storage and analysis.  
Figure 9: Five steps of executing the proposed model.  
Figure 11: Drone path planning of topographic map in four zones using Mission Planner software.  
Figure 10: Topographic map of HOBO U30 Weather Station Starter Kit in four zones.