## 3 Results
#### 3.2.1.
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**ID** & \begin{tabular}{c} **Type of** \\ **Proposal** \\ \end{tabular}  & \begin{tabular}{c} **Type of** \\ **Device** \\ \end{tabular}  & \begin{tabular}{c} **Sensors/Actuators** \\ \end{tabular}  & \begin{tabular}{c} **Microcontrollers** \\ **Microcontrollers** \\ \end{tabular}  & \ \begin{tabular}{c} **Wireless** \\ **Standards** \\ \end{tabular}  & \begin{tabular}{c} **Software** \\ **Infrastructure** \\ \end{tabular}  & **Ref. ** \\ \hline
**S53** & Prototype & Aquarium & \begin{tabular}{c} Waterproof Temperature Sensor, Load \\ Cell, Servo Motor, Light Sensor, Water \\ Pump, Infrared Sensor \\ \end{tabular}  & \ \begin{tabular}{c} Arduino Uno \\ Wi-Fi 32 \\ \end{tabular}  & \begin{tabular}{c} Wi-Fi \\ WiFiNIA Library \\ \end{tabular}  & [75] \\ \hline
**S54** & Prototype & Feeder & \begin{tabular}{c} Load Cell, Servo Motor, Detachable \\ Pill Container \\ \end{tabular}  & \ \begin{tabular}{c} Arduino Uno \\ Wi-Fi 32 \\ \end{tabular}  & \begin{tabular}{c} Wi-Fi \\ WiFiNIA Library \\ \end{tabular}  & [75] \\ \hline
**S55** & Prototype & Feeder & \begin{tabular}{c} TEMF600 (Light Sensor), Load Cell, \\ RFID MFRC522, RTC DS1307, SG90 \\ Servo Motor \\ \end{tabular}  & \ \begin{tabular}{c} Arduino Uno \\ Mini \\ \end{tabular}  & \begin{tabular}{c} Wi-Fi \\ WiFi \\ WiFiNIA \\ \end{tabular}  & \beginThe heterogeneity in hardware and software used in the analyzed pet device prototypes shows a clear focus on simplicity and low cost. Some of the prototypes featured high-quality finishes, while others used lower-quality casings. In all cases, the objective of each proposal was to demonstrate and validate the designs in practical terms. In terms of the hardware, the most common microcontrollers used in the development of prototypes were ESP32, Arduino, and Raspberry Pi, which are widely valued for their affordability and adaptability. These microcontrollers allow for the integration of various low-cost sensors, such as pH, temperature, motion, and proximity sensors, which meet the basic requirements of prototypes without high precision demands. This choice of components is especially suitable in an academic context, where the goal is to investigate and experiment with reduced costs. Furthermore, the analyzed prototypes mainly included accessible and easy-to-use sensors for food dispensers, smart collars, mini pet houses, or pet robots. Low-cost sensors, such as motion sensors, cameras, temperature and humidity sensors, and GPS and weight sensors, stand out for their ease of implementation, allowing developers to focus on the functional development of their prototypes. These sensors, along with basic actuators like servo motors and gear motors, enabled researchers to build functional prototypes that adequately address basic pet care needs without the need for high-end hardware. Some of the prototypes utilized timers or counters for scheduling feeding actions. The software infrastructure also adapts to cost constraints. Many of the prototypes utilized IoT platforms, which offer tools for managing and storing data in the cloud economically and simply. This software choice allowed for the implementation of dashboards integrating functionalities such as remote control and real-time monitoring with low maintenance requirements. Messaging and notification platforms, such as Telegram (e.g., S51) and WhatsApp (e.g., S5), were also used to add alert features to the prototypes, enhancing their ability to interact remotely with users. Some of the proposals utilized assistants such as Google Assistant (e.g., S43, S47, S62, and S64) or Alexa (e.g., S1) to enable natural interaction with the prototype. Regarding cloud computing, several of the analyzed devices in this study integrated cloud computing services.