                 return accelerometerDataCharacteristic.startNotifying()
             } else {
                 let promise = Promise<Characteristic>()
-                promise.failure(CenteralError.characteristicNotFound)
+                promise.failure(CentralError.characteristicNotFound)
                 return promise.future
             }
         }
         dataSubscriptionFuture.onFailure {error in
-            if error.domain != CenteralError.domain || error.code == CentralExampleError.PeripheralNotConnected.rawValue {
+            if error.domain != CentralError.domain || error.code == CentralExampleError.PeripheralNotConnected.rawValue {
                 self.presentViewController(UIAlertController.alertOnError(error), animated:true, completion:nil)
             }
         }

                return accelerometerUpdatePeriodCharacteristic.read(10.0)
            } else {
                let promise = Promise<Characteristic>()
                promise.failure(CenteralError.characteristicNotFound)
                return promise.future
            }
        }

                return peripheral.discoverPeripheralServices([serviceUUID])
            } else {
                let promise = Promise<Peripheral>()
                promise.failure(CentralError.peripheralNotConnected)
                return promise.future
            }
        }.flatmap {peripheral -> Future<Characteristic> in
