Adafruit Feather 32u4 Adalogger is an all in one datalogger designed and produced by Adafruit. Feather is a new development board series from Adafruit. As the name suggests, Feather boards are thin and light. Feather is designed to be a new standard for open source development platforms.
Adafruit Feather 32u4 Adalogger is based on Atmel’s ATmega32u4 processor clocked at 8 MHz and at 3.3V logic. ATmega32u4 has 32K flash and 2K RAM and built in USB support. Therefore this chip not only has USB-to-Serial program & debug capability readily (and there is no need for an FTDI-like chip), but also it can act like a mouse or a keyboard when connected to a computer.
For easy use in portable projects, Adafruit added a connector suitable for their 3,7V Lithium polymer batteries and built in battery charging. There is no need for a battery because the board can be powered directly from the micro USB connector. If you want to use it with a battery, you are also free to run your project with a battery and then plug in the USB for the battery to be recharged. Feather boards will automatically switch over to USB power when it is available. The battery is also tied through a divider to an analog pin, so it is possible to measure and monitor the battery voltage and detect when it needs a recharge.
The board has a USB bootloader, so you can use it with the Arduino IDE. The pack also includes some headers for you to solder them and use in your projects or on your breadboard.
Note: USB cable and Li-Po battery are not included.
Adafruit Web Page: https://www.adafruit.com/products/2795