title: PolideaHow can set Notify value to True on a specific Characteristic and Polidea/RXBluethootKit with IOS
body: <p>Hi I'm trying to write some Data to a device via BLE, I'm using RXBluethootKit for Swift but I have difficult to set Notify "on" in a specific characteristic before write a value.</p>
  
  <p>this is my code:</p>
  
  <pre><code>func connect(for state: BluetoothState)  -&gt; Observable&lt;Characteristic&gt;   {
          return manager.observeState()
              .startWith(state)
              .filter { $0 == .poweredOn }
              .flatMap { _ in self.manager.scanForPeripherals(withServices: [self.PERDIX_UUID]) }
              .take(1)
              .flatMap { $0.peripheral.establishConnection()
              .flatMap { $0.discoverServices([self.PERDIX_UUID]) }.asObservable()
              .flatMap { Observable.from($0) }
              .flatMap { $0.discoverCharacteristics([self.PERDIX_CHAR_UUID])}.asObservable()
              .flatMap { Observable.from($0) }
      }
  
  
  connect(for: state)
              .subscribe(onNext: { characteristic in
                  print("Discovered characteristic: \(characteristic.characteristic.uuid)")
                  self.result.text = characteristic.characteristic.uuid.uuidString
                  characteristic.writeValue(data as Data, type: .withResponse)
                      .subscribe { event in
                          //respond to errors / successful read
                  }
  
          })
  </code></pre>
  
  <p>Any suggestion?
  thanks</p>