Leonardo R3 ATmega32u4 Development Board with USB Cable

Specifications:

• Microcontroller: ATmega32u4
  
• Operating Voltage: 5V
  
• Input Voltage (Recommended): 7-12V
  
• Digital I/O Pins: 20
  
• PWM Channels: 7 (Pins 3, 5, 6, 9, 10, 11, and 13)
  
• Analog Input Channels: 12 (A0-A5, and A6-A11 on digital pins 4, 6, 8, 9, 10, and 12)
  
• DC Current per I/O Pin: 40 mA
  
• Flash Memory: 32 KB (of which 4 KB is used by the bootloader)
  
• SRAM: 2.5 KB
  
• EEPROM: 1 KB
  
• Clock Speed: 16 MHz

Key Applications

• Custom Macro Keypads: Create dedicated hardware buttons for video editing (Premiere/DaVinci) or gaming.
  
• Accessibility Tools: Build custom sip-and-puff or joystick-based mouse controllers for users with limited mobility.
  
• Security Research: Develop HID-based automation scripts (Rubber Ducky style) for authorized penetration testing.
  
• Industrial Data Logging: Use the separated Hardware Serial (UART) to talk to sensors while keeping the USB port free for PC communication.
  
• DIY Sim-Racing Gear: Create custom button boxes or handbrake controllers that the PC recognizes as a standard Gamepad.

Project Evolution

• Past Projects (Prerequisites): If you've mastered the basic Arduino Uno and find yourself frustrated that you can't easily emulate a keyboard or that the Serial port is "busy" when you try to use it with sensors...
  
• Feature Upgrade: ...this Leonardo R3 unlocks Native HID. You no longer need "FLIP" software or custom firmware on a secondary chip. The main processor handles it all. It also gives you 12 analog inputs—double that of a standard Uno!
  
• Effort/Requirements: Intermediate. You’ll need the standard Arduino IDE and the Keyboard.h or Mouse.h libraries (included by default).

Virtual Technician & Wiring

• ⚠️ Voltage Warning: While the board can take up to 20V via the DC jack, we strongly recommend staying between 7V and 12V. Overheating the regulator is the #1 cause of board failure.
• Logic Safety: This is a 5V logic board. If you are connecting it to 3.3V sensors (like ESP32 or newer sensors), use a logic level converter to prevent damage.

Package Includes:

1 x Leonardo R3 ATmega32u4 Development Board with USB Cable

Frequently Asked Questions (FAQ)

1. What is the main difference between Leonardo and Uno?
   The Leonardo uses the ATmega32u4 which has built-in USB, allowing it to act as a keyboard/mouse.
2. Does it come with a cable?
   Yes, this listing includes a high-quality Micro-USB data cable.
3. Why doesn't my computer recognize the board immediately? Ensure you are using the provided data cable. "Charge-only" cables will not allow the computer to see the board.
4. How do I make it act like a keyboard?
   Use the #include <Keyboard.h> library in your Arduino sketch.
5. Can I use Uno shields with the Leonardo?
   Most shields are compatible, but check pin 13 and SPI pin locations as they differ slightly.
6. What is the maximum voltage for the Vin pin?
   Recommended 7-12V; absolute limit 20V.
7. How many analog pins does it have?
   It has 12 analog inputs (A0-A11).
8. Can I use it as a MIDI controller?
   Yes, with libraries like MIDIUSB, it can act as a native MIDI device.
9. Why does the COM port change when I upload a sketch?
   This is normal for ATmega32u4 boards as the USB controller resets during upload.
10. How do I recover if a "runaway" keyboard sketch locks my PC? Hold the Reset button, click 'Upload' in the IDE, and release the button when the IDE says "Uploading."
11. Does it support I2C?
    Yes, on pins 2 (SDA) and 3 (SCL).
12. Is it compatible with Windows 11?
    Yes, it uses standard HID drivers built into all modern OSs.
13. Can I power it via the 5V pin?
    Yes, if you have a regulated 5V supply, but be careful not to reverse polarity.
14. What is the clock speed?
    It runs at 16 MHz.
15. How much current can the 3.3V pin provide?
    Up to 50 mA.
16. Is the bootloader pre-installed?
    Yes, it comes ready to use with the Arduino IDE.
17. Can I emulate a Gamepad?
    Yes, using 3rd party libraries like "Joystick."
18. What USB connector does it use?
    It uses a standard Micro-USB port.
19. How many PWM pins are available?
    There are 7 PWM pins.
20. Is this board original Arduino or compatible?
    This is a high-quality ProMax compatible board, tested and verified by Probots.