Arduino-Compatible Nano 3.0 , Great for small projects

Specifications:

• Microcontroller:ATmega328
• Operating Voltage (logic level): 5 V
• Input Voltage (recommended): 7-12 V
• Input Voltage (limits): 6-20 V
• Digital I/O Pins: 14 (of which 6 provide PWM output)
• Analog Input Pins: 8
• DC Current per I/O Pin: 40 mA
• Flash Memory: 16 KB (ATmega168) or 32 KB (ATmega328) of which 2 KB used by bootloader
• SRAM: 1 KB (ATmega168) or 2 KB (ATmega328)
• EEPROM: 512 bytes (ATmega168) or 1 KB (ATmega328)
• Clock Speed: 16 MHz
• Dimensions: 0.73″ x 1.70″

Power:

The EDArduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source.
The FTDI FT232RL chip on the Nano is only powered if the board is being powered over USB. As a result, when running on external (non-USB) power, the 3.3V output (which is supplied by the FTDI chip) is not available and the RX and TX LEDs will flicker if digital pins 0 or 1 are high.

Memory

The ATmega168 has 32 KB of flash memory for storing code (of which 2 KB is used for the bootloader); the ATmega328 has 32 KB, (also with 2 KB used for the bootloader). The ATmega328 has 1 KB of SRAM and 512 bytes of EEPROM (which can be read and written with the EEPROM library); the ATmega328 has 2 KB of SRAM and 1 KB of EEPROM.

Input and Output

Each of the 14 digital pins on the Nano can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins have specialized functions:
Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the corresponding pins of the FTDI USB-to-TTL Serial chip.