The open source Firmata project lets you connect Arduino to many other things.
Now you can connect your idevice to your Arduino via Bluetooth Low Energy.
Currently supports the Seeed Studio Xadow BLE device as well as the Redbear shield.
You need to upload the Standard Firmata sketch to your Arduino.
Important: This project requires a Bluetooth LE Capable Device (iPhone 4s and later; iPad 3 and later; iPod Touch 5; iPad mini) and will not work on the simulator.
We're open source. See our website to view our source code, compile your own version, or build your own app.