BLE app to blink an led as many times the input

Hi,
My intention is to build a BLE application to blink an led as many times the number given as user input. I am using flutter_blue plugin( https://pub.dev/packages/flutter_blue). Also, I’ve imported ‘dart:convert’ for the utf8 conversion. I am getting the user input with TextEditingController(). Here is a piece of my code.
BluetoothCharacteristic characteristic;
final _writeController = TextEditingController();

             TextField(
                                  keyboardType: TextInputType.text,
                                  controller: _writeController,
                            ),

           FlatButton(
                              child: Text("Send"),
                              onPressed: () {
                              characteristic.write(utf8.encode(_writeController.value.text));
                              Navigator.pop(context);
                              },
                           ),
 But, the led is blinking corresponding ascii value times the user input. For example, when the user input is 5, the led is blinking 53 times. Please, help me get through this problem.