## 3 Results
An oscilloscope was utilized to determine how well synchronized are the devices of a system. In the proposed method of synchronization, it was determined to only take 1.262 ms on average for a slave board to receive a command message since the master board sent it. Thus, slave boards are considered synchronized to the master board. The time it takes for a command message to be transmitted is not constant; hence, the difference  
Figure 5:1 Data-transmission characteristics with respect to distance: (a) average latency; (b) success rate. Figure 5:2 The number of obtained data points in relation to distance. in times that both slave boards receive a command message must also be measured. The oscilloscope experiment revealed an average difference of 0.998 ms, as seen in Figure 13a. Based on this value, slave boards are considered to be synchronized with each other. Taking the results of both experiments into account, in further research, the whole system (both slave boards and the master board) is denoted as perfectly synchronized. In the alternative synchronization method, it was determined that the differences in times that both slave boards receive a synchronizing message cluster around the mean of 1.211 ms and 2.130 ms, as seen in Figure 13b, with a standard deviation of 0.279 and 0.345, respectively. Slave boards thus can be assumed to be synchronized. But, on average, they are more out of sync, and the dispersion is greater than the proposed method of synchronization. Taking the results of the long-corridor experiment and the oscilloscope experiment into account, the alternative method was declared as inferior to the proposed method, and further experiments were conducted using the proposed synchronization method. The delay and stability of communication were also evaluated by conducting an experiment in an open field along a busy road. The results of this experiment are presented in Figure 5:3 Brief drops in the success rate can be seen throughout the experiment. At an approximately 100 m distance, the connection success rate became equal to 0%, as indicated by a red zone in the average delay graph. The connection resumed shortly after, but the success rate did not rise back to prior values. Presumably, the communication failure and brief drops in signal reliability were caused by passing cars and the close presence of smart devices. The impact of obstacles on the proposed system's functionality was tested by separating the master and slave microcontrollers with a varying number of concrete walls. The connection between the slave and master devices through one solid concrete wall was stable and of low latency (Figure 15). The connection through two solid concrete walls had frequent drops in success rate (as indicated by the red zones in the average delay graph), and the overall latency was higher (Figure 16). The connection was not possible through three concrete walls. It can be concluded that, with each wall between the communicating devices, latencies increased and the communication success rate decreased. As seen in Figures 15 and 16, it was found that, with each additional wall, the quality of the connection decreased. Through one wall, the connection remained stable. Through two walls, delays and data loss were observed. Through three walls, the connection was completely absent. In comparison, communication remained stable in an open area and a long corridor at a distance smaller than 100 m.  
Figure 5:4 The difference in time of each slave board receiving a synchronization message: (**a**) using the proposed method of synchronization; (**b**) using the alternative method of synchronization. Figure 5:5 Connection-quality measurements when two walls separate the master and slave microcontrollers: (**a**) average delay (red zones indicate timeframes of 0% success rate); (**b**) success rate. Figure 5:6 Measurement latency in an open field along a busy road: (**a**) average delay (red zone indicates a timeframe of 0% success rate); (**b**) success rate.