## 5 Conclusions  
Today, the rapid evolution of the Internet of Things (IoT), with billions of interconnected devices, is opening new possibilities for innovative services that make our lives easier, safer, and healthier. Wearable devices represent a versatile technology in the IoT paradigm, enabling non-invasive and accurate data collection directly from the human body for a wide range of applications, including health monitoring, assistance for impaired people, accident detection or prevention in industrial environments, etc. In particular, the proposed research work presents the development of a smart garment to monitor working conditions in particularly dangerous workplaces (e.g., food, chemical, and metallurgical industries). In particular, the wearable device integrates several sensors deployed in different \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Work** & **\# of Biophysical/Behavioral** & **\# of Environmental** & **Availability of** & **Invasiveness** \\  & **Parameters** & **Parameters** & **Harvesting Section** & **Invasiveness** \\ \hline
[15] & 0 & 3 & No & Medium \\  & (AT a, CO, CH4) & & & \\ \hline
[16] & 1 & 3 & No & Medium \\  & (collision) & (AT, RH b, CH4) & & \\ \hline
[26] & 1 & 2 & No & Low \\  & (HR) & (LPG and CO) & & \\ \hline
[24] & 1 & 5 & 5 & No & Low \\  & (Activity level) & (AT, RH, NO2, CO2, NH3) & & \\ \hline
[25] & 4 & 9 & & \\  & (BT c, HR, Activity level) & (UV, sound level, AT, RH, & No & Low \\  & & P d, UV e, O2, CO, O3) & & \\ \hline
[30] & 4 & 5 & 5 & No & Medium \\  & (HR, SpO2, Activity Level) & (AT, P, Altitude, Smoke, CO2) & & & \\ \hline \hline \end{tabular}  
* Air temperature; b relative humidity; c body temperature; d environmental pressure; e ultraviolet radiation.  
\end{table} 
Table 6: Comparison of our smart garment with other similar devices reported in the scientific literature considering the number of acquired environmental and biophysical parameters, availability of the harvesting section, and invasiveness. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**HR** & **HR** & **SpO2** & **SpO2** & **BT** & **BT** & **AT** & **AT** & **AT** & **At** & **AspO2** & **ABT** & **AAT** \\
**MAX30102** & **Model Check** & **MAX30102** & **CoCooBear** & **MAX30102** & **HT-820d**  
human body positions for acquiring the user's vital signs (HR, SpO\({}_{2}\), body temperature, and falls) and environmental parameters (e.g., concentrations of harmful gas species and oxygen level). The core section is represented by a custom acquisition and processing board based on the SAMD21G8A microcontroller and BLE transceiver (model JDY-23). Specifically, electrochemical gas sensing modules were developed and integrated into the wearable device for detecting the air concentrations of CO, H\({}_{2}\)S, CH\({}_{2}\)O, and O\({}_{2}\). The smart garment wirelessly transmits the acquired data to the cloud platform (IBM Cloud), where they are displayed, processed, and stored. Specifically, a custom mobile application was developed, which collects data from the wearable device and sends them to the cloud platform by the MQTT protocol, acting as an IoT gateway and, thus, enabling the system's operation in areas where a WiFi hotspot is not available. Moreover, the smart garment comprises a multisource energy harvesting system for recovering energy closely associated with the human body, such as light, body heat, and limb movements, using thin-film photovoltaic panels, TEGs, and flexible piezoelectric transducers. Field tests indicated that the harvesting section could scavenge up to 260 mW in real operating conditions, fully covering the energy requirements of the sensing and processing system in all tested scenarios. Nevertheless, the 380 mAh LiPo used to store the charge extracted from the harvesting section can ensure a lifetime of 16 days when no energy contributions are available. Finally, the characterization and tests on the sensors integrated into the garment confirm their correct operation. Conceptualization, R.D.F. and P.V.