Bluetooth / 802.15.1 Development Tools Adafruit Feather 32u4 Bluefruit LE

Description

Feather is the new development board from Adafruit. It is thin and light and was designed to be a new standard for portable microcontroller cores.
Bluetooth Low Energy is the new low-power, 2.4GHz spectrum wireless protocol. In particular, its the only wireless protocol that you can use with iOS without needing special certification and it's supported by all modern smart phones. This makes it excellent for use in portable projects that will make use of an iOS or Android phone or tablet. It also is supported in Mac OS X and Windows 8+.
At the Feather 32u4's heart is at ATmega32u4 clocked at 8 MHz and at 3.3V logic. This chip has 32K of flash and 2K of RAM, with built in USB so not only does it have a USB-to-Serial program & debug capability built in with no need for an FTDI-like chip, it can also act like a mouse, keyboard, USB MIDI device, etc.