## 3 Results
Each data point in the graph indicates the communication delay, while the master microcontroller and slave microcontrollers were at an indicated distance from each other. We assume that movement was constant, and the displacement during one communication is negligible. Figure 11 shows that 83.2% of the total transmission latency is less than the average, but increasing the distance leads to increasing latency variation and the appearance of failed attempts to transfer the data. It can also be noted that, even as the average delay increased, the mode of the delay was still around 7 ms, which is a typical delay, as previously shown in Figure 8. The measured average latency and success rate of transmitting data in a long corridor are shown in Figure 11, where the success rate represents how many  
Figure 8: Data transmission on the local ad hoc network latencies. communications out of the attempted communications were successful (communication is held to be successful if both data-gathering modules return data within the allowed timeframe after the master board sends out a request for data). Figure 11 shows a correlation between increasing delay and decreasing success rate while the distance grows. To obtain a full set of data, the master microcontroller must successfully communicate twice, once with each slave microcontroller. The master microcontroller must successfully send out both its messages (control command and request for data) and receive data messages, and this needs to happen for both slave microcontrollers. Figure 11b shows an average amount of successful communications during an attempt to obtain a full line of data during each second of the experiment, where time is proportional to the distance between the master and slave devices. Figure 10: Latency’s relationship with distance between the slave and master microcontrollers in the long corridor. Figure 9: Intervals between queuing a message to be sent and the message being received: Tx\({}_{11}\)—transmission of control command (ordering to gather data) to the left slave microcontroller, Tx\({}_{1R}\)—transmission of control command (ordering to gather data) to the right slave microcontroller; Tx\({}_{21}\)—transmission of control command (allowing to send data) to the left slave microcontroller; Tx\({}_{2R}\)—transmission of control command (allowing to send data) to the right slave microcontroller; Rx\({}_{12}\)—data message from the left slave microcontroller; Rx\({}_{2R}\)—data message from the left slave microcontroller. The corridor experiment was repeated using the alternative method of synchronization. Because the alternative method utilized one-way communication, the round-trip delay could not have been calculated. An approximate one-way delay could have been obtained by comparing the timestamp of a message being sent and the timestamp of it being received. Eventually, a more direct characteristic of obtained data points per second was chosen, the values of which are displayed in Figure 5:0  
It can be observed that throughout the majority of the experiment, the data-acquisition rate was constant, at around 20 samples per second, except for an increase to around 75 samples per second for a short duration. Having repeated the experiment multiple times, one or two spikes were observed appearing at different times during the experiment. It can thus be assumed that such a pattern is caused not by the environmental conditions of the experiment but by the interplay between the low-level implementation of the ESP-NOW communication protocol and the high-level implementation of the synchronization algorithm. More specifically, the issue is presumed to arise from received data processing and exporting being performed simultaneously with incoming data collection; meanwhile, in the proposed method, these processes are performed sequentially. Not only does the system display instability, but the data-acquisition rate at close range is lower than that of the proposed method (which is, on average, equal to 24.6 samples per second).