The UNO is the best board to get started with electronics and coding. If this is your first experience tinkering with the platform, the UNO is the most robust board you can start playing with. The UNO is the most used and documented board of the whole Arduino family.

Arduino Uno is a microcontroller board based on the ATmega328P (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started. You can tinker with your UNO without worrying too much about doing something wrong, worst case scenario you can replace the chip for a few dollars and start over again.

"Uno" means one in Italian and was chosen to mark the release of Arduino Software (IDE) 1.0. The Uno board and version 1.0 of Arduino Software (IDE) were the reference versions of Arduino, now evolved to newer releases. The Uno board is the first in a series of USB Arduino boards, and the reference model for the Arduino platform; for an extensive list of current, past or outdated boards see the Arduino index of boards.

Specifications:

• Microcontroller ATmega328P
• Operating Voltage 5V
• Input Voltage (recommended) 7-12V
• Input Voltage (limit) 6-20V
• Digital I/O Pins 14 (of which 6 provide PWM output)
• PWM Digital I/O Pins 6
• Analog Input Pins 6
• DC Current per I/O Pin 20 mA
• DC Current for 3.3V Pin 50 mA
• Flash Memory 32 KB (ATmega328P) of which 0.5 KB used by bootloader
• SRAM 2 KB (ATmega328P)
• EEPROM 1 KB (ATmega328P)
• Clock Speed 16 MHz
• LED_BUILTIN 13
• Length 68.6 mm
• Width 53.4 mm
• Weight 25 g