title: Core Bluetooth doesn't find peripherals when scanning for specific UUIDs
body: <p>so I'm pretty new when it comes to bluetooth and I'm currently trying to make it scan for devices, if I try to scan for all devices by using this: </p>
  
  <pre><code>self.centralManager.scanForPeripherals(withServices: nil, options: nil);
  </code></pre>
  
  <p>it finds several devices and I printed out the uuidStrings and got several devices uuids but when I try to search for those specific uuids it doesn't find anything, the is the code I'm using:</p>
  
  <pre><code>private var uuidArray = ["8B2F2570-9E3B-1FB6-C76E-9258526B662B",
                           "4A29E654-F59F-53AD-D7F6-B435B8BBAB78",
                           "48F038D0-246C-4D62-A025-1D822CAFB93A",
                           "D8E13B7A-BB89-45C2-8747-BAE1D94AE9E0",
                           "558CF744-2C4F-439F-AD7F-E2212938123B",
                           "967B98AC-FFE7-45EC-8D25-0276FBD57FC8"];
  
  func scanForPeripherals (timeout: Double) -&gt; Bool {
      if (self.centralManager.state != .poweredOn) {
  
          print ("[BLE] Central Manager is not powered on");
          return false;
      }
      print ("[BLE] Start Scan");
  
      Timer.scheduledTimer(timeInterval: timeout, target: self, selector: #selector(stopScan), userInfo: nil, repeats: false)
  
      var services: [CBUUID] = [];
  
      for uuid in uuidArray {
          let cbuuid = CBUUID(string: uuid);
          services.append(cbuuid);
      }
  
  
      self.centralManager.scanForPeripherals(withServices: services, options: nil);
      return true;
  
  }
  </code></pre>
  
  <p>am I missing something here? anyone knows how to find specific devices?</p>