Characteristics and Write Value

   func peripheral(peripheral: CBPeripheral, didDiscoverCharacteristicsForService service: CBService, error: NSError?){
        for characteristic in service.characteristics! {
            let thisCharacteristic = characteristic as CBCharacteristic
            if thisCharacteristic.UUID == txCharacteristic{
                self.currentCharacteristic = thisCharacteristic
                let openValue = "1".dataUsingEncoding(NSUTF8StringEncoding)!
                self.peripheral.writeValue(openValue, forCharacteristic: self.currentCharacteristic, type: CBCharacteristicWriteType.WithResponse)
            }
        }
        if let error = error {
            print("characteristics error", error)
        }
    }
    
    func peripheral(peripheral: CBPeripheral, didUpdateValueForCharacteristic characteristic: CBCharacteristic, error: NSError?){
        if let error = error {
            print("updated error", error)
        }
    }
    
    func peripheral(peripheral: CBPeripheral, didWriteValueForCharacteristic characteristic: CBCharacteristic, error: NSError?){
        if let error = error {
            print("Writing error", error)
        } else {
            print("Succeeded")
        }
    }