## 4 Discussion and Conclusions  
The industrial safety system proposed is an efficient and innovative form of human-machine interaction, which agrees with what is proposed in Industry 4.0. It has an interface where the voice assistant can deliver information in a friendly way, more naturally and understandably for the human. In its programming, different variants can be added in the synthetic voice and the statements for the delivery of information. Therefore, it is possible to have pleasant conversations to ascertain process status, abnormal situations, and existing alarms with a simple voice command. This work demonstrates that it is possible to give voice commands to an industrial machine to control it or obtain information, such as the engine's current or temperature. In the industrial field, safety is essential. It is programmed into the Alexa skill, and the password is vocalized for the user before turning on the motor. IoT platforms today guarantee communication mechanisms between each other to develop and implement applications in which management and transfer of information, and reading and writing data are needed. The system's implementation uses Alexa devices, smart devices, Arduino modules, VoiceFlow, Node-Red, Blynk, Tuya Smart Platform, and IFTTT. The system is appropriately functioning through get, post, and update requests. But these technologies strongly depend on internet connectivity. The ESP32 microcontroller board and the Blynk platform can provide IoT features to Arduino modules, sensors, or compatible devices. It has been possible to integrate the current sensor and the vibration sensor with the Tuya Smart intelligent devices in the cloud, allowing them to manipulate and access their information. Lastly, this kind of technology provides remote access, in addition to voice control, to industrial devices to provide more intuitive and friendly work environments. This kind of technology (voice assistants) is widely used in home applications, but recently, it has been used in the health field (hospitals) and industry. Human-machine interaction represents the future through voice commands, so it is necessary to propose industrial devices and research solutions that can respond to vocal commands. There are works that involve voice assistants, such as [14; 15], that interact with an industrial robot. In the first case, the authors use Kinetic by Microsoft as the interface between the robot and the human. In the second case, the authors develop a human-robot interface based in neural network structure, but we have not found any work that operates an industrial machine with commercial intelligence, such as an artificial voice assistant like Alexa. We use this kind of technology (Alexa) to provide a voice interface between an industrial electric engine and human (operator). This interface is more easy and intuitive for the machine's operator with the novelty of providing an access code (password) for the operation of the engine. The password gives more security in the machine operation in an industrial environment. In this work, we use commercial devices (Alexa, Arduino modules, Alexa's sensor, and Alexa's relays) with algorithms that we developed to give the electric engine the intelligence for interacting with an operator. This technology gives the possibility, in the near future, that the engine's operator could work more safety and easily. In tests conducted with the voice assistant, problems were encountered in recognizing voice commands when placed in an environment with high noise intensity. Efficiency drops drastically compared to tests under normal (no noise) conditions, specifically from \begin{table}
\begin{tabular}{c c c c} \hline \hline
**No.** & **Thermometer (\({}^{\circ}\)C)** & **Temperature Sensor (\({}^{\circ}\)C)** & **Error** \\ \hline
7 & 33 & 32.70 & 0.91\% \\ \hline
8 & 35 & 34.60 & 1.14\% \\ \hline
9 & 37 & 37.50 & 1.25\% \\ \hline
10 & 39 & 39.30 & 0.77\% \\ \hline \hline \end{tabular}
\end{table} 
Table 7: _Cont._approximately 94% to 75.45%.