## 3 Wireless Sensor System Deployment
### WSN Deployment  
After analyzing the radio characteristics of the scenario, this section presents the deployment of the ZigBee-based WSN within the workshop. The results for both scenarios, as presented in the previous section, suggest that positioning the network coordinator in the middle of the workshop would improve the RF propagation, particularly avoiding the walls in the corners, i.e., avoiding NLoS situations. Thus reducing the low coverage areas and improving end-to-end communication within the entire scenario. The proposed locations of the coordinator (marked as 'C') and the five workstations monitored by sensor nodes are illustrated in Figure 11. Depending on the characteristics and requirements of each workstation, the sensor nodes' components differ, but in general, they consist of an Arduino UNO board, an IO Shield expansion, digital push buttons, a matrix keypad, KY-032 and KY-033 passive infrared (PIR) sensors from Joy-IT, real-time Clock (RTC) modules for synchronization, and an XBee 3c module for the ZigBee wireless communications, operating at its higher transmitted power level (i.e., 8 dBm). The difference between KY-032 and KY-033 modules is the detection distance. The KY-032 module can detect obstacles 40 cm away from the sensor, while the KY-033 module has a maximum detection range of less than 10 cm. Figure 12 presents schematically the implemented sensor nodes and coordinator/gateway, as well as a real sensor node and its encapsulation, ready to be deployed. Figure 11: Schematic view of the WSN deployment within the workshop (‘C’ represents the ZigBee-network coordinator/gateway). Five workstations have been selected for real-time monitoring due to their importance in the fabrication process of the solar curtains. Figure 13 shows the deployed sensor nodes on the five workstations. As can be seen, different number of nodes have been deployed depending on the parameters to be monitored on each workstation. The roles of the sensor nodes and the goals behind its implementation within each workstation are described below:  
* Workstation 1: The knife cutting machine (see Figure 13a). In this node, both KY-033 and KY-032 sensors have been used. IR obstacle sensor KY-033 is used to detect the passage of the cutting blade. With this, it detects the time that elapses between the different cuts. Moreover, IR obstacle sensor KY-032 detects when the fabric roll is deposited. This results in the time that elapses in the search for tissue. The green pushbutton is used to terminate each product that has been made and the red pushbutton is used to collect the time of searching for tissue scraps. Finally, the Keypad is used to enter the identification of the operator, the number of scraps that have been taken and the production order to be made. This node has been implemented with the aim of collecting the following data: Production order that is being carried out; operator identification; time at which production times are being carried out (preparation and search time for the fabric, time between each cut of fabric, collection of the semifinished product, total time). * Workstation 2: Laser cutting machine (see Figure 13b). The IR obstacle sensor KY-032 detects when the fabric roll is deposited. This results in the time that elapses in the search for tissue. The green pushbutton is used to terminate each product that has been made and the red pushbutton is used to collect the time of searching for tissue scraps. Finally, the 3 \(\times\) 4 Matrix Keypad is used to enter the identification of the  
Figure 12: (**a**) The implemented sensor nodes and Coordinator/Gateway; (**b**) Picture of a sensor node; (**c**) The node encapsulated. operator, the number of scraps that have been taken and the production order to be made. When the machine is with the laser on (cutting), the laser value is obtained directly from the PLC of the machine.