Adafruit Itsy Bitsy 32u4 - 5V 16MHz

Adafruit Itsy Bitsy is a small, powerful, Arduino-compatible microcontroller board. It's very compact, but still with a bunch of pins.

It's only 35mm long by 18mm wide. but has 6 power pins, 6 analog & digital pins and 17 digital pins. It packs much of the same capability as an Arduino UNO. So it's great once you've finished up a prototype on a bigger Arduino, and want to make the project much smaller.

Specifications:

• ATmega32u4 onboad chip in QFN package
• 5V power and logic, 16MHz clock rate, 2KB RAM and 28K FLASH
• USB bootloader with a nice LED indicator, AVR109 compatible (same as Flora, Feather 32u4, Leonardo, etc)
• Micro-USB jack for power, USB uploading and debugging, you can put it in a box or tape it up and use any Micro USB cable for when you want to reprogram.
• Can act as a USB HID Keyboard, Mouse, MIDI or plain USB 'CDC' serial device (default)
• On-board 5.0V power regulator with 150mA output capability and ultra-low dropout. Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
• Low current 3.3V regulator output from chip, for small sensors
• Power with either USB or external output (such as a battery) into VBAT pin - it'll automatically switch over
• On-board red pin #13 LED
• 23 GPIO total - 6 analog in, 1x SPI port, 1x I2C port, 1x Hardware Serial port and 10 more GPIO, 4 of which have PWM
• Can drive NeoPixels, connect to sensors, servos, etc.
• Reset button for entering the bootloader or restarting the program.
• Dimensions: 35mm x 18mm x 4,1mm
• Weight: 2,6g