Development Board Arduino Leonardo

The Arduino Leonardo is a development board based on the ATmega32u4 microcontroller running at 16 MHz. It integrates 20 digital I/O pins (7 PWM-capable), 12 analog inputs, 32 KB flash memory, 2.5 KB SRAM and 1 KB EEPROM. The board includes a micro USB connector, power jack, ICSP header and reset button and can be powered via USB, an AC-to-DC adapter or battery. Built-in USB communication allows the Leonardo to present itself to a connected computer as a virtual COM port and also as USB HID devices such as a keyboard or mouse.

Advantages

The Leonardo’s ATmega32u4 with native USB avoids the need for a secondary USB-to-serial processor, simplifying the design and enabling direct USB device emulation. Compact dimensions (53.3 x 68.6 mm) and light weight (about 20 g) make the board convenient for embedded and portable projects. Standard power specifications (operating at 5 V, recommended input 7–12 V) and common interfaces (digital, analog, ICSP) provide compatibility with existing Arduino shields and many peripherals.

Suitable for

• USB HID projects (keyboard, mouse emulation)
• Prototyping microcontroller-based devices
• Educational electronics and workshops
• Embedded projects requiring compact, low-weight boards

Key specifications

• Microcontroller: ATmega32u4
• Clock speed: 16 MHz
• Flash: 32 KB; SRAM: 2.5 KB; EEPROM: 1 KB
• Digital I/O: 20 pins (7 PWM outputs)
• Analog inputs: 12
• Operating voltage: 5 V
• Input voltage (recommended): 7–12 V; maximum rated input up to 20 V
• Interfaces: micro USB, power jack, ICSP header, reset button
• Dimensions: 53.3 x 68.6 mm; Weight: ~20 g
• Manufacturer: Arduino; MPN: A000057; EAN: 8058333491141

How to use

Connect the Leonardo to a computer via a micro USB cable to program it using the Arduino IDE and to provide power. Alternatively, supply power through the barrel power jack or an appropriate battery within the recommended voltage range. Select the correct board and port in the IDE, upload sketches as usual, and use the available digital and analog pins for sensors, actuators and communication. When using USB HID features, configure the sketch to emulate keyboard or mouse behavior; the board will enumerate as the chosen device when connected.

Recommendations

Use a stable 7–12 V power source when powering through the barrel jack and avoid supplying voltages above the board’s rated maximum. For reliable USB HID operation, test device enumeration on the target host system and ensure sketches properly handle USB reconnection and debouncing of input events.