# InoT Sensor Network for Wild-Animal Detection near Roads
## 2 Materials and Methods
### DSN Mounting  
The existing road infrastructure was used for mounting the DSN units. Several mounting options were considered, but, for the realization of the sensor-network installation, the designs of DSNs that do not require mechanical intervention to the roadside-marker posts were chosen. Two mounting options are presented in Figure 3. The standard unmodified roadside-marker post is shown in Figure 3a. The DSN node shown in Figure 3b is mounted on top of a standard roadside-marker post. In this case, the DSN node is incorporated into the standard roadside-marker post without significant and visible design and dimension changes of the original roadside-marker post. The mounting variant from the side of the DSN node to a standard roadside-marker post is shown in Figure 3c. It has a smaller volume of the casing which results in better sealing, the smaller mass of the DSN, and is better protected from snow plowing during the winter period and water or snow splashing from passing trucks during rain or thaw. However, mechanical intervention to the roadside-marker post is necessary during installation (drilling or gluing), and the available area for mounting the solar panel is small. The solar panel can appear in the shadow of the roadside-marker post as well. The implementation of the case (Figure 3b) does not require a change in the dimensions of the roadside-marker post (width, depth, and height). The standard shape of the roadside-marker post is maintained and visual appearance changes from the driver seat are not noticeable. This design is used for DSNs of generation 1 and generation 2. The main advantage of the (b) mounting case is simple installation to the already existing roadside-marker posts. The solar panel is mounted on the top of the DSN module where a larger area for a solar panel is available, which results in better exposure to the Sun. The DSN node sensors can be blocked by grass and bushes, and the mechanical damage risk during grass mowing, snow plowing operations, or road construction works is higher. The inclination angle of the solar panel in normal conditions is required for the best available average exposure angle to the Sun. However, in the case of the DSN installation, the inclination angle cannot be adapted to be oriented at the optimum horizontal angle. It mostly depends on the road section's orientation. For example, the best solar energy capture would be ensured in the road section which has the direction from west to east with the solar panel oriented to south. The idea of the flat top was also considered for equalizing the solar energy capture for all available road orientations, but flattening the top of the DSN case would result in a smaller area for the solar panel, which is very important for better energy harvesting. The flat top would result in water and snow deposits, and the dust could not be washed by rain and would accumulate faster on the surface of the solar panel. Therefore, a vertical angle similar to the original was chosen which allows for the achievement of a visual appearance match by sacrificing some of the energy efficiency of the  
Figure 2: DSN internal structure. solar panel due to a nonoptimal vertical angle. The optimal electricity production occurs when the solar panel faces south at approximately the angle of the location's latitude. In Lithuania, it would be approximately 54 degrees. The installed system can be used on both sides of the road. In this case, the performance of nonoptimally installed nodes could be partially backed up by those that are under better conditions, or the installation can be not performed for those road sections that appear in permanent shadow or the DSNs that have solar panels inclined to the north. Figure 4 shows a more detailed DSN 3D visualization. The body of the DSN assembly is 3D printed using white printing material. Three PIR sensors are mounted on the back walls of the DSN, facing from the road towards the forest.