The Arduino Nano is a small development board, which is particularly well suited for direct development on breadboards. Through the USB connection software updates can be applied quickly and easily.

Arduino Nano (again a China clone)

The board can be powered via USB. In this case, 3.3 V is available through the FTDI232RL chip, which is also responsible for the USB communication. But this results in a major drawback if you want to use the board in finished circuits without USB powering and use, for example, 3.3V sensors, because an additional voltage converter is necessary then.

Specifications:

• ATMEL ATmega328 with 32KB Flash-RAM (2KB used by bootloader),
  2KB SRAM and 1KB EEPROM, clocked at 16MHz
• 14 digital inputs and outputs (including 6 PWM channels)
• 8 analog inputs
• I²C support
• serial port
• USB mini connector (FTDI232RL chip)
• separate ICSP connector
• 3.3 V are provided by the FTDI chip, but only when connected to USB
• USB powered, or separately

Example projects with Arduinos:

Sensors: Temperature & humidity measurements with the DHT11
A 1.8 inch TFT color display (HY-1.8 SPI) and an Arduino

Components:

eBay:	Arduino Nano
Amazon:	Arduino Nano

Good?