# Low-Cost Wireless Sensing System for Precision Agriculture Applications in Orchards
## 4 Conclusions  
In this study, a simple, low cost, and low energy consuming wireless sensor system was developed, deployed, and evaluated. The star communication protocol was selected as the most appropriate for the sake of simplicity in communication and programming, which facilitated low energy consumption. Using this protocol and with a communication range longer than 250 m, as measured in the experimental orchard, this system can safely cover the needs of orchards and any other agricultural fields, sized up to 36 ha, with only one network. This network can support up to seven nodes in a 30 min data acquisition cycle, or 14 nodes in an hourly cycle, both of which are adequate solutions for orchards of such size. The novelty of the developed system lies in the fact that it uses a dummy device as Coordinator which through simple but advanced programming can receive, process, and send data packets from all End-nodes to the cloud. Two Coordinator programming modes were examined, both showing reliable operation; (i) the Coordinator serving both as a central node and as End-node (receiving measurements for itself, receiving data packets from the rest of network's nodes, reforming messages and sending to cloud), and (ii) the Coordinator serving only as a central node (receiving data packets, reforming messages and sendingto cloud). The first option is suggested for small networks of up to three nodes, while the second is the ideal solution for situations where more sensing locations are required (3 to 14 End-nodes). The laboratory and in-field tests confirmed reliable, continuous, and independent operation of the developed system in agricultural environments.  
The orchard's size was typical for the southern European conditions, thus, the results of this application apply to the majority of agricultural fields. Temporally stable management zones were derived from soil field measurements. The analysis performed using a fuzzy clustering algorithm on soil ECa and elevation data acquired from the experimental orchard, providing better categorization when delineating into three management zones, which is quite common for fields of such size (4 ha). Combining management zones and 3D point cloud data derived from UAS can prove particularly handy for efficient wireless sensor nodes allocation, setting the nodes at representative locations of each subsection of the field, and improving communication.  
Conceptualization, A.C.T.; Methodology, A.C.T.; Validation, A.C.T., D.K., R.B. and D.B.; Formal Analysis, A.C.T.; Investigation, A.C.T.; Resources, A.C.T., D.B.; Data Curation, A.C.T.; Writing--Original Draft Preparation, A.C.T.; Writing--Review & Editing, A.C.T., D.K., D.B., R.B.; Visualization, A.C.T., D.B.; Supervision, A.C.T., D.B.; Project Administration, A.C.T., D.B.; Funding Acquisition, D.B., A.C.T. All authors have read and agreed to the published version of the manuscript.  
This research has been supported by the European Union and Greek national funds through the Operational Programme Competitiveness, Entrepreneurship and In-novation, under the call RESEARCH-CREATE-INNOVATE (project code: T1 EDK-03987) <<BioCircular: Bioproduction System for Circular Precision Farming>>.  
The authors declare no conflict of interest.