Arduino Leonardo ATmega32U4 Development Board

The Arduino Leonardo R3 Development Board is a feature-rich microcontroller board based on the ATmega32U4, offering native USB connectivity without requiring a separate USB-to-serial converter. Running at 5V and 16MHz, it is ideal for robotics, automation, IoT, educational projects, and USB Human Interface Device (HID) applications. Thanks to the ATmega32U4's integrated USB functionality, the Leonardo can emulate a USB keyboard, mouse, joystick, MIDI device, and other custom USB peripherals while remaining fully compatible with the Arduino IDE.

Key Specifications

• Microcontroller: ATmega32U4
• Operating Voltage: 5V
• Clock Speed: 16MHz
• Recommended Input Voltage: 7V to 12V
• Input Voltage Limits: 6V to 20V
• USB Interface: Micro USB with native USB support
• Digital I/O Pins: 20
• PWM Outputs: 7
• Analog Inputs: 12
• Flash Memory: 32KB (4KB used by bootloader)
• SRAM: 2.5KB
• EEPROM: 1KB
• DC Current per I/O Pin: 40mA
• 3.3V Pin Current: 50mA
• Board Dimensions: 68.6mm × 53.3mm

Features

• Native USB connectivity eliminates the need for a separate USB-to-serial converter.
• Compatible with the Arduino IDE for simple programming and rapid prototyping.
• Can function as a USB keyboard, mouse, joystick, MIDI controller, or other HID device.
• 20 digital I/O pins provide extensive connectivity for sensors, displays, motors, and peripherals.
• Seven PWM outputs for LED dimming, motor control, and servo applications.
• Twelve analogue inputs for precise sensor measurements.
• Includes a DC barrel jack, Micro USB connector, ICSP header, and reset button.
• Built-in bootloader allows sketches to be uploaded directly over USB.

Applications

• USB keyboards and macro pads
• Gaming controllers and custom HID devices
• Robotics and automation
• IoT and smart home projects
• Sensor data acquisition
• STEM education and prototyping
• MIDI controllers and interactive installations

Programming Notes

• Select Arduino Leonardo from the Tools > Board menu within the Arduino IDE before uploading sketches.
• The onboard bootloader allows programming directly over the Micro USB connection without requiring an external programmer.
• The board can also be programmed through the ICSP header if required.

Resources

• Arduino Leonardo Schematic (PDF)
• ATmega32U4 Datasheet

Looking for a smaller ATmega32U4 development board? Check out the Arduino Pro Micro 5V, which offers the same native USB capabilities in a much more compact form factor. You can also browse our complete Arduino collection to find the right board for your next project.

New to Arduino? Follow our Arduino Getting Started Guide to learn the basics, then build your first project using our LED Blink Tutorial.

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