Arduino Uno R3 Development Board ATmega328P.

• Microcontroller (MCU):
• IC: Microchip ATmega328P (8-bit AVR core)
• Clock Speed: 16 MHz on Uno board, though IC is capable of 20 MHz maximum at 5 Volts
• Flash Memory: 32 KB, of which 0.5 KB used by the bootloader
• SRAM: 2 KB
• EEPROM: 1 KB
• USART peripherals: 1 (Arduino software default configures USART as a 8N1 UART)
• SPI peripherals: 1
• I²C peripherals: 1
• Operating Voltage: 5 Volts
• Digital I/O Pins: 14
• PWM Pins: 6 (Pin # 3, 5, 6, 9, 10 and 11)
• Analog Input Pins: 6
• DC Current per I/O Pin: 20 mA
• DC Current for 3.3V Pin: 50 mA
• Size: 68.6 mm x 53.4 mm
• Weight: 25 g
• ICSP Header: Yes
• Power Sources:
• USB connector. USB bus specification has a voltage range of 4.75 to 5.25 volts. The official Uno boards have a USB-B connector, but 3rd party boards may have a miniUSB / microUSB / USB-C connector.
• 5.5mm/2.1mm barrel jack connector. Official Uno boards support 6 to 20 volts, though 7 to 12 volts is recommended. The maximum voltage for 3rd party Uno boards varies between board manufactures because various voltage regulators are used, each having a different maximum input rating. Power into this connector is routed through a series diode before connecting to VIN to protect against accidental reverse voltage situations.
• VIN pin on shield header. It has a similar voltage range of the barrel jack. Since this pin doesn't have reverse voltage protection, power can be injected or pulled from this pin. When supplying power into VIN pin, an external series diode is required in case barrel jack is used. When board is powered by barrel jack, power can be pulled out of this pin.

1*Arduino UNO R3
1*USB cable