ESP32 series microcontrollers have become an essential component for creation and control of smart devices and robots. They offer good performance, balanced power consumption, compactness, ease of application and affordability. In this study, the device, architecture, parameters, and numerous studies and systems based on the ESP32 microcontrollers are discussed. A functional analysis of the reviewed publications was made, classifying categories and areas of application of microcontrollers. The advantages and disadvantages of these microcontrollers are presented, and directions for future applications and development are set. In addition, a comparative analysis of ESP32 microcontrollers and Raspberry Pi Pico microcontrollers, all based on ARM architecture, is done. The results obtained show improved performance on the ESP32, while lower power consumption is reported on the Raspberry Pi Pico. An example of implementing firmware to process data from a sensor and connect to a data collection and management system has been proposed. The data processing capabilities of microcontrollers are shown in order to achieve the concept of edge computing. This experiment shows the wide application of controllers and possibilities for working with real-time processes.