# IoT-Ready Temperature Probe for Smart Monitoring of Forest Roads
## 4 Simulation and Experimental Result Comparison and Discussion
This phenomenon is expected and arises primarily due to the parameters of the probe installation environment, e.g., subsoil. Analyzing the results of the temperature probe 1 (Figures 19-21) and probe 2 (Figures 22-24) sensors, it is clear that the transport delay between the individual sensors is approximately 120 s (Probe 1) and 480 s (Probe 2). Considering the heat transfer rate in the ground (asphal road, construction materials, subsoil) in Figure 26, where the delay among sensors is from 4 to 6 h, the own transport delay of the temperature probe is negligible. the number of sensors used in the probe grows due to the need for individual cabling for each installed sensor. Cabling then represents a significant parameter affecting the probe measurements--due to the amount of wire metal used. There is a considerable degree of influence on the installed sensors and subsequent measurements. Presented solution uses a custom PCB design with glass-laminate backing and conductive copper connections. Due to the usage of DS18B20 digital thermometers, the copper used is optimized for only 2 conductive paths. Therefore, we were able to reduce the metal used significantly and thus reduce the parasite influences. Another benefit is the possibility of deploying sensors at precisely defined distances. This is ensured by the PCB design, where in the case of our experimental probe we used a 50 mm pitch, which defines the maximum density of sensors placement. This pitch can be modified to other values such as 10 mm by simply changing the PCB design. The modularity of the probe is ensured by the usage of several PCB modules, which can be connected by jumpers and, if necessary, shortened at designated locations, which are indicated on the PCB silkscreen in front of the installed sensor. We have designed the probe housing in two versions using two different materials. Both designs are applicable to forest road environments. The difference is perceived mainly in terms of practical installation in the forest road, taking into account the need to drill a hole with the least possible diameter in order not to disturb the subsoil and thus affect the measurements significantly. The probe uses 1-wire technology, which is widely known and often directly used in a number of available IoT solutions. This solution therefore allows the probe to be connected to data loggers, measurement control panels, stand-alone data acquisition solutions as well as online connectivity via communication converters or IoT solutions, making the probe a rather versatile device. Furthermore, in our opinion, this is a new solution for forest roads, as the forest road area, although similar in nature to the general road area, has specific requirements for the equipment used. In our case, we have started to design a solution for the measurement of the vertical temperature profile of forest roads as part of a research project to gather information on subsoil freezing progress. In addition, the solution for the measurement of the horizontal temperature profile has already been validated from previous activities [40; 41]. The said solution also uses 1-wire technology. Figure 12:0 Vertical temperature measurements during one week. In additional support of our novelty claims, we note that the novelty of our solution may also be supported by the granted utility model number SK122021U1 [42]. The measured data, once processed, will enter the forest road management system, where it should be part of a predictive model for preventive maintenance and repair planning. The predictive model will have a higher relevance after the addition of other parts of the measurement system and the measurement of more annual cycles. However, this activity is not part of our temperature probe design and is beyond the scope of this manuscript. Although the proposed probe is suitable for its intended use in the management of forest road environments, we see further opportunities for modifications and improvements in order to maximize the range of its applications.