BTLE
Arduino library for basic Bluetooth Low Energy support using the nRF24L01+ (basic support = sending & receiving on the advertising broadcast channel)
You will also need to install the RF24 library from https://github.com/floe/RF24
Note: the BTLE class and the examples are licensed under GPLv3. However, the helper functions in btle.inc are (C) 2012 by Dmitry Grinberg under a separate license (see file for details).