## 2 Technologies Involved
### Internet of Things  
The Internet was conceived as a global network to offer services such as WWW (World Wide Web) or FTP (File Transfer Protocol) to enable computers and users to communicate and exchange information. However, in recent years the storage and processing capacity of other kind of devices has improved significantly, providing them with the necessary resources for their integration into the global network. Furthermore, communication technologies are also evolving and electronic devices are becoming smaller and more affordable, making objects in our environment belong to what is known as the Internet of Things (IoT), a dynamic global infrastructure network with auto-configuration capabilities based on communication protocols and open standards, where all kinds of devices called \"things\" remain interconnected, interacting and working together to achieve common goals. Figure 1 presents an outline of the interactions that occur between the different entities of the IoT. IoT involves, in the context of wireless sensor networks (WSNs), connecting objects to the Web, allowing them communicating with other devices, objects, and people [6].  
These devices are able to communicate with their environment by exchanging data and information captured and autonomously, reacting to events in the physical world. It is referred to as smart devices or smart things [7]. When we talk about smart devices, we mean any object in our environment capable of capturing and collecting information, transmitting it through the existing network infrastructure, receiving data from the network it belongs to, and acting in certain established conditions [8].  
An IoT device generates a lot of data that must be stored and processed; however, the storage and processing capabilities of these devices are often limited. For this reason, the ability to transmit information autonomously from IoT devices through standard Internet protocols enables the storage of such data in external storage systems that provide persistence and processing capabilities. Within IoT architecture, these features belong to what are considered intermediate layers or middleware, that is, a software layer between the physical devices and applications that allow the developer to select the details of various underlying technologies and contribute to a rapid prototyping of service-oriented applications. The third layer would form the applications that consume data stored in the intermediate layer. Moreover, communication with smart devices can be bidirectional, so that some information sent to these devices may cause activation, according to established conditions.  
The main components of an IoT device are [9]:  
1. Control Unit: usually a microcontroller or microcomputer with a single integrated circuit containing a processor, memory, and programmable input/output. This input/output can be programmed to collect data from physical devices (e.g., sensors) or to control external devices (e.g., LED screens or engines).
2. Sensors: Devices responsible for measuring a physical quantity (temperature, humidity, etc.) and converting it into a signal that can be read and interpreted by the control unit.
3. Communication Module: component device consisting of an electronic module that provides independent connectivity through communication protocols by using a wired or wireless network.  
This communication module can be configured through an intermediate node or direct Internet connection nodes.
4. Power Supply: A small battery and a solar cell provided with any device for power supply loading.