# InoT Sensor Network for Wild-Animal Detection near Roads
## 4 Experiments
Tests have confirmed that LED flashing in the mod does not trigger the PIR sensor;
* The photoresistor for determining the dark time of the day is abandoned, using a modified solar battery voltage measurement circuit solution for this purpose;
* Two options for installing the DSN on the roadside-marker post were proposed: by cutting off its upper part (visually more solid) or by screwing it on and fixing it on the upper part of the unmodified roadside-marker post. It was decided to use a thermal imaging camera (Hikvision DS-2 TD2617-6/PA). The thermal images taken for visual reference are of relatively low resolution (160 \(\times\) 120) for identification of the presence of wildlife and classification of the source of the triggering instead of a hunting camera with night illumination to check the reasons for the activation of the second generation DSN sensors (Figure 12). The IoT network changed after starting to use the second generation of DSN sensors. LoRa gateway stores triggering data received  
Figure 11: Photos of the installed first generation of DSN nodes with various types of optical contamination: (**a**) Raindrops on the sensor opening; (**b**) Organic particles and raindrops on the sensor opening with the installed canopy. Figure 12: The second-generation DSN mounted on a roadside-marker post. from the DSN sensors. The same gateway is used to control and store data received from the thermal camera. Both data sets' pictures and triggering logs are sent to the cloud server using a 4G modem once per day. It is possible to configure the LoRa gateway to send all the data (photos and logs) immediately, but, at the experiment site, the 4G network is unstable. Therefore, it was decided to store all data locally and send it to the cloud periodically. It was decided to use a thermal imaging camera instead of a hunting camera with night illumination to check the reasons for the activation of the second series ASM sensors. After analyzing the thermal imaging cameras available on the market, the original idea of using a battery-powered camera was rejected due to the relatively short operating time of the camera (depending on the model, lasting from a few to a dozen hours). After consultation with the customer and after obtaining permission from the Road Directorate, it was decided to install a thermal imaging camera (160 \(\times\) 120 pixels) fed from the network. Photo cameras used near the Road Directorate on a roadside-marker post are located at km 41. The data-collecting device with a camera was installed on the roadside-marker post. The thermal imaging camera can record both photos and thermal imaging images. For data-protection purposes, only the thermal images are recorded. The data acquisition during the system research duration is continuous (24/7). The photographing and data-saving period of the data-acquisition system was set to 10 s. The selected setup and sampling period allows identification of the false activations of DSN sensors in those cases when the DSN sensor was activated, but no wild animals were photographed in the investigated area. These cases, when an animal was photographed in the investigated area, but the sensors were not activated, can be identified as well. Tests of the second-generation DSN with modified data registration and verification nodes with a thermal imaging camera were installed and tested from October 2021 to February 2022. On 4 December 2021, the sensors stopped sending signals. After checking, it was noticed that their fastening part was broken, and the DSN was lying on the side of the road. While observing the snow-clearing works on the road, it was noticed that the clearing truck shook the roadside-marker posts quite strongly while clearing the snow. In the case of negative temperatures, this could have been the reason for the breakdown of the fasteners. It was also noticed that one of the PIR sensors of one DSN was turning on significantly more often than other DSNs. It was found that it was reacting to passing cars.