I am playing a project to search iBeacons in region by Arduino with BLE Shield.
Because of leak of tech-support of iBeacons Technology, I can't find any docs about how to search iBeacons signal source.
An iBeacon is basically a BLE Broadcaster, and such devices can only be discovered by a Central or an Observer. Many BLE shields use Nordic Semiconductor's nRF8001 chip, and unfortunately, this is a pure Peripheral device, and as such, it isn't possible to use this to discover an iBeacon.
Take a look at this question for further details on the roles in BLE.
来源：https://stackoverflow.com/questions/19374865/how-to-use-arduino-with-ble-shield-search-apples-ibeacons-signal-source