The Arduino Pro Micro is a compact, USB-native development board built around the ATmega32U4 microcontroller. Unlike standard Arduino boards, the Pro Micro features built-in USB communication, allowing it to emulate keyboards, mice, and other HID (Human Interface Device) peripherals.
Core Specifications
Microcontroller: ATmega32U4 (with built-in USB support)
Operating Voltage: 5V (3.3V version also available)
Clock Speed: 16 MHz (5V) / 8 MHz (3.3V)
Flash Memory: 32KB (4KB used by bootloader)
SRAM: 2.5KB
EEPROM: 1KB
I/O & Connectivity
Digital I/O Pins: 18 (of which 9 provide PWM output)
Analog Input Pins: 12 (10-bit resolution)
Built-in USB: Native USB support (appears as HID device)
Communication Interfaces: UART, I2C, SPI
DC Current per I/O Pin: 40mA
Power & USB
Input Voltage: 5V (regulated via USB) or RAW input (6-12V)
USB Connectivity: Micro-USB
Power Consumption: ~20mA (active mode)
Physical Dimensions
Size: 18mm x 33mm
Weight: ~5g
Breadboard-Friendly: Yes
Key Advantages
Native USB Support: Acts as a USB device without additional chips (great for custom input devices).
Compact Size: Smaller than the Nano, making it perfect for wearables and embedded projects.
Versatile I/O: 18 digital pins (9 PWM) and 12 analog inputs (shared with digital pins).
Performance & Memory
16MHz clock speed (5V version) or 8MHz (3.3V version for low-power applications).
32KB Flash (with 4KB used by the bootloader).
2.5KB SRAM and 1KB EEPROM for data storage.
Connectivity & Expansion
12 analog inputs (more than Nano or Uno).
Hardware UART, I2C, and SPI for connecting sensors, displays, and wireless modules.
Micro-USB port for easy programming and power.
Power Efficiency
Can be powered via USB (5V) or RAW input (6-12V).
3.3V version available for low-power applications.
Applications
✔ Custom HID Devices (keyboards, game controllers, MIDI controllers).
✔ Compact Embedded Systems (wearables, drones, IoT nodes).
✔ Sensor Projects (12 analog inputs for multi-sensor setups).
Why Choose the Pro Micro?
USB HID Capability: Unlike Nano/Uno, it can emulate USB devices.
More I/O Pins: 18 digital pins vs. Nano's 14.
Smaller Footprint: 18x33mm vs. Nano's 18x45mm.
Package Includes: 1 x Arduino Pro Micro