Wouldn't it be great if you could control or access your electronics project, robot, or anything awesome you are up to these days from your phone? Now you easily can with this Bluetooth LE breakout Board. The Bluefruit LE SPI Friend makes it easy to add Bluetooth Low Energy connectivity to anything with 4 or 5 GPIO pins. With SPI, you don't have to worry about baud rates, flow control, or giving up a hardware UART port. Connect to your Arduino or other microcontroller using the common four-pin SPI interface (MISO, MOSI, SCK and CS) plus a 5th GPIO pin for interrupts (to let the Arduino know when data or a response is ready).
This board has a standard UART interface for debugging and testing. You can simply connect it to and Arduino's Rx and Tx pins or connect an FTDI cable to test/debug on your computer.
The board is capable of much more than just sending strings over the air! Thanks to an easy to learn AT command set, you have full control over how the device behaves, including the ability to define and manipulate your own GATT Services and Characteristics, or change the way that the device advertises itself for other Bluetooth Low Energy devices to see. You can also use the AT commands to query the die temperature, check the battery voltage, and more, check the connection RSSI or MAC address, and tons more.For more info check Adafruit's guide for Bluefruit LE UART Friend.