Display BLE Advertisement Data and when it changes

ViewController.swift

import UIKit
import  CoreBluetooth

class ViewController: UIViewController, CBCentralManagerDelegate, CBPeripheralDelegate {
    var centralManager:CBCentralManager!
    var queue:dispatch_queue_t!
    var datas = [String : String]()
    var peripherals = [CBPeripheral]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        queue = dispatch_queue_create("MyBLE", DISPATCH_QUEUE_SERIAL)
        centralManager = CBCentralManager(delegate: self, queue: queue);
    }
    
    func centralManager(central: CBCentralManager!, didDiscoverPeripheral peripheral: CBPeripheral!, advertisementData: [NSObject : AnyObject]!, RSSI: NSNumber!) {
        
        if (!contains(peripherals, peripheral)) {
            peripherals.append(peripheral)
        }
        
        let key = peripheral.identifier.UUIDString
        let data = advertisementData.description
        
        if let previous = datas[key] {
            if (previous != data) {
                println("Different \(peripheral.name): \(data)")
            }
        } else {
            println("\(peripheral.name): \(data)");
            datas[key] = data
        }
        
    }
    
    func centralManagerDidUpdateState(central: CBCentralManager!) {
        println("centralManagerDidUpdateState");
        if (central.state == .PoweredOn ) {
            println("Scanning")
            centralManager.scanForPeripheralsWithServices(nil, options:[CBCentralManagerScanOptionAllowDuplicatesKey:true]);
        }
    }
}