Leonardo R3 Development Board (Arduino-Compatible)
Take your interactive projects to the next level with the Leonardo R3 Development Board. While it shares the same familiar footprint and shield compatibility as the classic Uno, the Leonardo features a major architecture upgrade. Powered by the advanced ATmega32u4 microcontroller, this board features built-in USB communication directly on the main chip.
By eliminating the need for a secondary USB-to-serial converter chip, the Leonardo R3 can connect to your computer and emulate a native USB Keyboard, Mouse, or Joystick. This opens up unique possibilities for creating custom gaming controllers, macro pads, human-machine interfaces (HMI), and assistive tech devices.
Key Features
Native USB Simulation: Powered by the ATmega32u4 with built-in USB 2.0 connectivity, allowing the board to act exactly like a standard plug-and-play USB keyboard or mouse when plugged into a PC.
Expanded Analog Inputs: Breaks out a massive array of 12 analog inputs (compared to the Uno's 6), making it perfect for complex sensor matrices and multi-axis joystick controllers.
More PWM Channels: Offers 7 dedicated Hardware Pulse Width Modulation (PWM) outputs for smoother motor control and precise LED dimming arrays.
Dedicated Hardware Serial: Because the USB port is handled internally, the main hardware UART serial port (Pins 0-RX and 1-TX) remains completely free to communicate with external GPS, Bluetooth, or Wi-Fi modules without interfering with your code uploads.
Shield Ecosystem Ready: Maintains the standard Arduino pin layout, ensuring full compatibility with your existing Uno shields, expansion boards, and standard Arduino IDE libraries.
Technical Specifications
Feature | Specification |
Microcontroller | ATmega32u4 |
Operating Voltage | 5V |
Input Voltage (Recommended) | 7V – 12V (via DC Barrel Jack or VIN pin) |
Input Voltage (Limits) | 6V – 20V |
Digital I/O Pins | 20 (of which 7 provide hardware PWM output) |
Analog Input Pins | 12 Channels (10-bit resolution) |
DC Current per I/O Pin | 40 mA |
Flash Memory | 32 KB (of which 4 KB is used by the bootloader) |
SRAM / EEPROM | 2.5 KB / 1 KB |
Clock Speed | 16 MHz |
USB Connector Type | Micro-USB |
Advanced Pinout & Interface Mapping
The Leonardo R3 expands your physical interfacing layout with multi-functional pin traces:
Power Rails: Flexible power routing via the standard 2.1mm center-positive DC Jack, a stable Micro-USB port, or directly through the VIN and GND header lines.
Hardware PWM Outputs: Allocated across pins 3, 5, 6, 9, 10, 11, and 13 for precise analog-write operations.
Built-in I2C & SPI Traces: Features dedicated SDA and SCL pins next to the AREF header for seamless sensor hookups. Note: Unlike the Uno, the SPI bus pins are only accessible via the central 6-pin ICSP header.
External Interrupts: Supports hardware external interrupts on pins 0, 1, 2, 3, and 7, giving you high-speed monitoring for encoders and safety sensors.
Common Applications
Custom Gaming Controllers: Build your own DIY arcade setups, flight simulator flight sticks, or racing steering wheels.
Productivity Macro Pads: Map complex keyboard shortcuts, video editing hotkeys, or programming macros to physical arcade buttons.
Industrial HMI Panels: Create dedicated, physical data-entry keypads or mouse-pointer controllers for machinery dashboards.
Assistive Technology: Build custom computer mice or keyboard switches tailored for users with unique accessibility needs.
Note for Developers: When uploading sketches via the Arduino IDE, ensure you select "Arduino Leonardo" from the Boards Manager menu. Because the USB port resets dynamically when a new program is flashed, your computer's assigned COM port may briefly change during the upload sequence—this is completely normal behavior for the ATmega32u4 architecture!
Package Includes:
1 x Leonardo R3 ATmega32u4 Development Board (Arduino-Compatible)