## 5 Discussion  
The IoT is a hot area where scientists of significantly different origins can meet, and thus, it is important to facilitate the establishment of a common basis, alleviating misunderstanding and favoring multidisciplinary, toward scientifically sound outcomes. Consequently, there is a lot of space for works shedding light on the physical and technical challenges related to the design, implementation, and evaluation of the core elements of an IoT platform, and this knowledge is essential for any potential enhancement of its functionality. Furthermore, IoT technology is mutually related with the scientific applications it is destined to support, and the environmental/agricultural area represents a significant amount of these applications and offers excellent exemplification for understanding the ways that several technical mechanisms can be adopted to and serve real scenarios. In this context, efficiently delivering soil sensor data provides fertile ground and a paradigm for understanding many of the physical and technical challenges towards fluently working IoT solutions. On the other hand, the task of reliably gathering and reporting soil-specific information for a long period is a complex process that has to overcome a lot of challenges (such as environmental factors, sensor module diversity, microcontroller characteristics, power constraints, and communication range limitations). Consequently, it demands elaboration beyond a simple hardware/software architecture description and data report  
Figure 18: The corresponding percentage of water content in the stone wool is plotted in relation to the days passed since the wetting took place using the TEROS 10 sensor (a strong linear relation). level. In response to these tasks, the most interesting contribution points of this work are summarized below:  
* The modern market of electronics can quite easily provide the necessary equipment for fluently supporting a wide range of environmental monitoring applications. Despite this fact, the diverse cost-effective components collected should be paired in a very careful manner to anticipate manufacturing imperfections and deviations. If these modules are properly calibrated against accurate units and complemented by the necessary software, they can deliver results matching the ones of much more expensive systems and offer better flexibility and openness. * The low energy footprint of the proposed soil monitoring system, thanks to the fine-tuned sleep/active cycle operation, results in fluent operation for more than 3 months on a single-cell Li-Ion battery of the 18,650 type (and with all five sensor elements installed on the end node and a frequent measurement report pattern), consequently eliminating the need for solar panel assistance. Nevertheless, in case such photovoltaic equipment is necessary, a small unit can easily replenish the energy spent during the nights. * Apart from the older ML2 sensing module, the rest of the components required lower current to function properly and had smaller warm-up times than the 2 s required for the ML2 instrument. Consequently, a small 5 V/0.5 W solar panel (placed above the ground) was more than enough for a fully autonomous operation, even if not properly aligned with the sun. This solution, though, should be applied in a rational manner, i.e., with respect to the constraints implied by the requirements for increased protection against malicious actions or intense environmental factors. * The setup practices suggest at least burying the batteries close to the sensors in order to eliminate their fatigue from environmental temperature extremes, and this may even lead to placing the whole node system (along with its antennas) underground to reduce installation complexity and achieve better protection against environmental extremes, unattended animals, or malicious persons. * In cases where the antennas are about to be buried under the soil surface, the LoRa protocol remains able to transmit the harvested data at satisfactory signal strength conditions.