# Monitoring Perishable Commodities Using Cellular IoT:
## 3 Results and Discussion
### Autonomy  
The evolution of current consumption of the datalogger over the entire autonomy test is illustrated in Figure 10, after conversion from voltage to current. This graph highlights the three main operating states of the datalogger, each with distinct current requirements. The current consumption in each state was analyzed in detail by zooming into the representative sections marked with red boxes, with current peaks highlighted during periods of activity with wireless communication (Figure 11), activity without wireless communication (Figure 12a) and accelerometer-triggered events (Figure 12b). In Figure 10, the maximum current consumption is observed during active wireless communication, which are the widest sections of the graph, around minutes 21 and 106, where the datalogger reaches its highest current peaks. During these periods, wireless transmission demands higher power than other operations, resulting in these peaks. Meanwhile, the shorter, lower sections of the graph correspond to activity without wireless communication, which draws less current than transmission phases. Additionally, small, sharp peaks indicate accelerometer events, representing minimal consumption as the system briefly wakes to record a vibration and then quickly returns to Deep Sleep mode. In between these operations, the datalogger remains in Deep Sleep, drawing almost no current. In Figure 11, which zooms into the activity with wireless communication, fluctuations and peak values are explained by specific stages of the datalogger's operation. The system first wakes up, initializing its modules, reflected as an initial rise in the graph. Following this, it measures and stores sensor data, causing a second rise, slightly higher than the first. The highest current peak of this stage, around 440 mA, corresponds to the establishment of the wireless connection, a task that requires significant power. Subsequently, as data from the flash memory are transmitted in packets, three oscillations appear, with each spike representing the power draw from transmitting one packet. Finally, an increase and then a decrease in current consumption follows as the entire system powers down and re-enters Deep Sleep. This section presents an average current of 113.42 mA. Figure 10: Evolution of the current consumption of the datalogger. Figure 11(a) shows a segment of activity without wireless communication, where consumption is notably lower than in the communication phase. Here, the datalogger wakes up, represented as an initial rise in the graph, measures and stores sensor data, causing a second, higher rise, and returns to Deep Sleep. This mode conserves energy by omitting the power-intensive communication tasks, leading to a more moderate current draw. These periods have an average current of 77.16 mA. Finally, Figure 11(b) zooms into accelerometer events, the smallest and shortest peaks in the overall test. In these instances, the datalogger wakes briefly, records vibration data and returns to Deep Sleep, a minimal operation that keeps power use low. These events have an average current of 13.18 mA. For the calculation of the average current \(I_{avg}\) during a period \(T\), Equation (10) was used, where \(i(t)\) is the continuous-time instantaneous current value, \(i_{k}\) is the discrete-time instantaneous current value during sampling, \(T_{s}\) is the sampling period and \(N=T/T_{s}\) is the number of samples during that period. \[I_{avg}=\frac{1}{T}\int_{T}i(t)dt\approx\frac{1}{T}\sum_{k=1}^{N}i_{k}T_{s}= \frac{1}{N}\sum_{k=1}^{N}i_{k} \tag{10}\]  
Table 6 shows the most representative values of the consumption, including the values mentioned so far, such as the average current, the maximum current, the average currents during the activity, the Deep Sleep and the accelerometer event. The system had an average current consumption (\(\overline{I}\)) of 7.91 mA with a maximum value in the test of 436.21 mA.