The Arduino UNO is the most widely used and documented development board in the Arduino ecosystem. Based on the ATmega328P microcontroller, it offers 14 digital I/O pins, 6 analog inputs, and USB connectivity for programming and serial communication. Ideal for beginners and professionals alike.

Specifications

• Microcontroller: ATmega328P
• Operating Voltage: 5 V
• Input Voltage: 7–9 V
• Digital I/O Pins: 14 (of which 6 support PWM)
• Analog Input Pins: 6
• DC Current per I/O Pin: 20 mA
• Flash Memory: 32 KB (ATmega328P)
  - 0.5 KB used by bootloader
• SRAM: 2 KB
• EEPROM: 1 KB
• Clock Speed: 16 MHz (ceramic resonator)
• USB Interface: Atmega16U2 (R3 version) or Atmega8U2 (R2 and earlier)
• Communication: UART, SPI, I²C
• Programming Interface: USB-B (via included cable)
• Power Jack: Barrel connector (2.1 mm centre-positive)
• ICSP Header: 6-pin for external programmer
• Reset Button: Onboard

Features

• Plug-and-play USB programming and serial monitoring
• Compatible with Arduino IDE and vast open-source libraries
• Breadboard-friendly layout with standard headers
• Ideal for embedded control, sensor interfacing, and educational projects
• Common use cases:
  - STEM learning and classroom kits
  - Robotics and automation controllers
  - Sensor data acquisition and logging
  - Serial-controlled relays, motors, and displays