# Real-Time Human Activity Recognition on Embedded Equipment: A Comparative Study
## 4 Implementation on Embedded Equipment
### Difference between Architectures  
The selection of devices aims to represent a diverse set of edge computing platforms, each with its unique strengths and use cases. The Raspberry Pi was selected for its versatility and computational power. As a single-board computer, it provides a Linux-based environment and is well-suited for running complex algorithms and applications. Its support for a wide range of peripherals and connectivity options makes it a popular choice for various IoT and edge computing projects. The STM32 microcontroller represents the category of microcontrollers commonly used in embedded systems. The STM32H753 ZI microcontroller features 3 user LEDs, 2 user and reset push-buttons, and a 32.768 kHz crystal oscillator. The board connectors include SWD, ST Zio expansion connector with ARDUINO(r) Uno V3 compatibility, and ST morpho expansion connector. Flexible power-supply options encompass ST-LINK USB VBUS, USB connector, or external sources. It offers comprehensive free software libraries and examples through the STM32 Cube MCU \begin{table}
\begin{tabular}{c c c} \hline \hline  & **String Datetime** & **Datetime Object** \\ \hline MicroPython on ESP32 & 16 octets & 16 octets \\ \hline MicroPython on STM32 & 16 octets & 16 octets \\ \hline Python on Windows machine & 68 octets & 48 octets \\ \hline C language on STM32 & 20 octets & 36 octets \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Measurement of in-memory size of string datetimes in Aruba dataset (obtained results). Package and supports a wide range of Integrated Development Environments (IDEs) such as STM32 CubeIDE. Various USB modes are supported such as USB Devices. Board connectors may include MIPI20 compatibility, USB with Micro-AB or USB Type-C\({}^{\circledR}\), and Ethernet RJ45. Furthermore, on-board ST-LINK (STLINK/V2-1, STLINK-V3E, or STLINK-V3 EC) debugger/programmer with USB re-enumeration capability facilitates mass storage, Virtual COM port, and debug port functionalities, enhancing the development process. Its real-time capabilities and low power consumption make it suitable for applications where resource efficiency is critical. The architecture of the Espressif ESP32 DevKit V4 centers around its core component, the ESP32-WROOM-32 module. This module integrates essential features such as the EN reset button and boot download button, which initiates firmware download mode for serial port firmware downloads. The board is equipped with a USB-to-UART bridge chip, enabling high-speed data transfer of up to 3 Mbps through the micro USB port. A 5V Power On LED indicates when the board is powered either through USB or an external 5V power supply. The board's I/O functionality is extensive, with most pins broken out to pin headers, allowing for versatile programming options including PWM, ADC, DAC, I2C, I2S, and SPI. Users have three power supply options: the default micro USB port, 5V and GND header pins, and 3V3 and GND header pins, providing flexibility in powering the board according to specific project requirements. The ESP32 was chosen for its low cost, low power consumption, and integration of wireless connectivity features, which contribute to its popularity in a variety of edge computing applications. Table 3 details the characteristics of each architecture. Regarding the processing time, there is a constraint to respect in this work, which is the following. Since an industrial system is multitasking, the processing time necessary to classify an activity must be less than the time between two events in the dataset. A