# A Novel Intelligent IoT System for Improving the Safety and Planning of Air Cargo Operations
## 2 System Description
### Hardware  
In this paragraph, the elements that form the INTELLICONT system are presented, alongside their main features. Figure 2 illustrates the various components of the system in block diagram form, as well as the way the various subsystems communicate and exchange data. Figure 1: The remote monitoring and control system architecture. Sensors: Four different types of sensors are mounted on the ULD, for measuring various parameters of the ULD's locking state and status during flight, as presented in Table 1.  
In each corner of the ULD's baseplate, which is mainly used for moving the ULD around and locking it in place inside the cargo compartment of the aircraft, there is a box of contact switches and position/magnetic sensors for monitoring the ULD's locking pins position and, via this, whether the ULD has been successfully locked in place. The ULD's locking pins comprise a ferromagnetic material, able to cause excitation to the magnetic sensors and, of course, push the contact switches inside the locking pin box. Each box contains two (2) contact switches and two (2) position sensors, for detecting the position of the locking pin. A pair of sensors consisting of a contact switch and a magnetic sensor is placed near the spot in which the ULD's baseplate comes into contact with the aircraft's cargo compartment baseplate so that the magnetic sensor can be excited and the switch can be pushed once the locking pin has been released from its box and locks the ULD securely onto the cargo compartment baseplate. The other pair is located deep inside the locking pin box and its sensors can be triggered only once the locking pin has been fully withdrawn, the ULD has been released from the cargo compartment baseplate and it can move. There are four locking pin boxes inside the ULD's baseplate, guaranteeing the ULD's secure locking during flight, and eight (8) contact and position sensors in them, ensuring proper monitoring of the locking state of the ULD both during the loading/unloading processes and during flight. Each ULD also incorporates three piezoelectric sensors that can monitor any impact on the container. The arrangement of the piezoelectric sensors on the ULD is as follows: one sensor is placed on the horizontal structural beam of the long side of the ULD, one is placed on the horizontal structural beam of the shorter side of the ULD, and one on the vertical structural shaft of the container. This placement provides better monitoring of the stresses which the container may suffer due to an impact. The smoke detector is placed on the container's ceiling, where smoke is quickly concentrated in case of fire. Table 2 presents the three types of sensors mounted on the ULD, along with their technical specifications. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Type** & **Use** & **Sensors per ULD** \\ \hline Piezoelectric sensors & Structural health monitoring (SHM) & 3 \\ Smoke detector & Fire, temperature, humidity & 1 \\ Contact switches & ULD lock status indication & 8 \\ Position sensors & ULD lock status indication & 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Type of sensors mounted on ULD. Figure 2: The INTELLICONT system hardware architecture, its main components, and the communication between them. RMC mainboard: The mainboard of the RMC is the cornerstone of its architecture and every peripheral component (piezoelectric sensors, smoke detector, contact switches, and position sensors) is connected to it. The board also undertakes the monitoring and control of their operations, along with data collection and its processing. It is powered by the power supply board, providing the necessary voltage levels for its operations. Lastly, the mainboard includes a USB port and a Wi-Fi communication module enabling the transmission of the received data to the HMI. Figure 3 demonstrates the utilized RMC mainboard. Microcontroller: The mainboard includes an ultra-low-power microcontroller, the MSP430F5359 by Texas Instruments.