The Arduino Leonardo is a microcontroller board based on the ATmega32U4, offering the same flash, RAM, and capabilities as the ATmega328 found in the Uno. The key difference is built-in USB communication, allowing the Leonardo to appear as a keyboard, mouse, or serial device to a connected computer — no secondary USB chip required.

With 20 digital I/O pins, 12 analog inputs, 7 PWM channels, and a micro USB connection, the Leonardo is ready for interactive projects straight out of the box. This version comes with all headers pre-soldered for easy breadboard and shield use.

Key Features

• Native USB – Built-in USB on the ATmega32U4 enables keyboard, mouse, and serial device emulation
• Pre-Soldered Headers – Ready for immediate use with breadboards and compatible shields
• 20 Digital I/O Pins – 7 usable as PWM outputs, with 40mA per pin
• 12 Analog Inputs – 10-bit resolution on pins A0–A11
• Multiple Power Options – Micro USB, DC power jack (7–12V), or VIN pin header

Specifications

• Microcontroller – ATmega32U4
• Operating Voltage – 5V
• Input Voltage – 7–12V recommended (6–20V limits)
• Interface – Micro USB
• Digital I/O Pins – 20
• PWM Channels – 7
• Analog Input Channels – 12
• DC Current per I/O Pin – 40mA
• DC Current for 3.3V Pin – 50mA
• Flash Memory – 32KB (4KB used by bootloader)
• SRAM – 2.5KB
• EEPROM – 1KB
• Clock Speed – 16MHz
• Board Dimensions – 70 × 55 × 14 mm (2.76 × 2.17 × 0.55 in)

Ideal For

• USB HID projects (custom keyboards, mice, game controllers)
• Interactive installations and MIDI controllers
• General-purpose electronics prototyping
• Learning embedded programming with Arduino

Package Contents

• 1× Arduino Leonardo (with headers)

Resources

• Schematic (PDF)
• Eagle Design Files
• ATmega32U4 Datasheet (PDF)