The Feather boards from 32u4 series – designed around ATmega32u4 – 3.3V logic supply and 8 MHz clock which is supported in the Arduino IDE and supported by a massive range of libraries.
Features Bluefruit LE as on-board Bluetooth module configured with multi-function code. It can transparently transmit back and forth from Bluetooth enabled smart device. You can utilise Adafruit’s App for both iOs and Android or write your own to talk to UART device.
The Adafruit Feather family are lightweight boards and designed to be a new standard for portable microcontroller cores. The Feather boards have built in USB so it is capable for USB-to-Serial program and debug without dedicated FTDI like chip. One of the great feature of Feather boards is built in battery charging and a connector for 3.7V LiPoly batteries.
Buy Feather 32u4 Bluefruit LE from Pakronics: