The Arduino Leonardo is included in the basic boards of Arduino technology but is not recommended for simple applications where you can use the Arduino Uno.

The main feature of the Leonardo board is that it uses a microcontroller with integrated USB and can be recognized as a keyboard or mouse.

The Arduino Leonardo is based on the ATmega32U4 microcontroller from Atmel. It is a complete board that contains everything needed to be programmed and operated by connecting it with a simple microUSB cable to your computer or with a power supply to the socket, and it can also operate with a simple battery. Specifically, the board has 20 digital inputs or outputs (7 of which can be used as PWM outputs and 12 as analog inputs), 1 microUSB port for programming and powering the board, 1 power input that can alternatively be used for power from a socket power supply or a simple battery, 1 ICSP socket, and finally a button for resetting the board. The microcontroller is synchronized at 16 MHz (Crystal 16MHz).

The Flash memory of the Arduino Leonardo where you can store your program (sketch) is 32KB, capable of accommodating most simple programs; if it is not enough, you can choose a larger Arduino board like the Arduino Mega 2560.

The Arduino Leonardo operates at low voltages, with a 5V DC power supply from the USB input or with 9V/12V DC from the power input, without the risk of electric shock.

The Arduino Leonardo is a similar board to the Arduino Micro because they use the same microcontroller (ATmega32U4) with integrated USB communication, allowing the computer to recognize them as keyboard or mouse devices and communicate with it without requiring a second microcontroller for communication like the Arduino Uno, which is based on the ATmega328 microcontroller.