How to verify a mfrc522 arduino uid in a wpf application

Question

0.00/5 (No votes)

See more:

Hi, I´m working on a Project, that verifies a UID in a WPF application when you pass a picc on the MFRC522 reader. Every time I´ve tried it looks like it didn´t recognised the picc.

The programm should theoretically work like this:

The Arduino MFRC522 shield looks for a picc, when it finds one it gets the uid and print it in the serial port.

The c# programm, then, reads what´s in the serial port and saves it in a variable. A void, then it verifies if that variable matches the UID with a 'if' loop and if matches a specific UID, sends to the port 'ok' if it doesn´t it sends 'no'.

And my programm, knowing what the uid is, and copying it to where it has to verify it, sends always no.

What I have tried:

Here is my arduino code:

#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN         9           // Configurable, see typical pin layout above
#define SS_PIN          10          // Configurable, see typical pin layout above

MFRC522 nfc(SS_PIN, RST_PIN);   // Create nfc instance.

MFRC522::MIFARE_Key key;

String dato;

void setup()
{
  Serial.begin(9600); // Initialize serial communications with the PC
  while (!Serial);    // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
  SPI.begin();        // Init SPI bus
  nfc.PCD_Init(); // Init nfc car
}


void loop()
{
  if(Serial.available()){
    delay(100);  
    while(Serial.available() > 0){
        // statement
        dato = Serial.readString();
    }
  }
  if(dato == "ok"){
      admited();
      dato = "";
  }
  if(dato == "no"){
      noAdmited();
      dato = "";
  }
  if ( ! nfc.PICC_IsNewCardPresent())
        return;

    // Select one of the cards
    if ( ! nfc.PICC_ReadCardSerial())
        return;
    // Show some details of the PICC (that is: the tag/card)
    Serial.println();
  for (byte i = 0; i < nfc.uid.size; i++) {
    Serial.print(nfc.uid.uidByte[i] < 0x10 ? "0" : "");
    Serial.print(nfc.uid.uidByte[i], HEX);
   } 
  
  delay(500);
  }

  void admited()
  {
    Serial.println();
    Serial.println("The picc is been admited");
  }

  void noAdmited()
  {
    Serial.println();
    Serial.println("The hasn´t been admiteed ");
  }

and here is my c# code:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO.Ports;
using System.Threading;

namespace nfc_to_wpf
{
    /// <summary>
    /// Lógica de interacción para MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        SerialPort port1 = new SerialPort();
        private delegate void SetTextDeleg(string text);
        string data_saved;
        string data2;

        public MainWindow()
        {
            InitializeComponent();
            loadConnections();
        }

        private void loadConnections()
        {
            port1.BaudRate = 9600;
            port1.PortName = "COM7";
            try
            {
                port1.Open();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            recieveData();
        }

        private void recieveData()
        {
            if (port1.IsOpen == true)
            {
                port1.DataReceived += port1_DataReceived;
            }
        }

        void port1_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {

            Thread.Sleep(100);
            try
            {
                string data = port1.ReadLine();
                Dispatcher.BeginInvoke(new SetTextDeleg(si_DataReceived), new object[] { data });
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }


            // Invokes the delegate on the UI thread, and sends the data that was received to the invoked method. 

            // ---- The "si_DataReceived" method will be executed on the UI thread which allows populating of the textbox. 


        }

        private void si_DataReceived(string data)  //Modifica la entrada del serial a legible
        {
            data_saved = data;
            tb1.Text = data_saved;
            tryToSend();
        }

        private void tryToSend()
        {
            if (port1.IsOpen == true)
            {
                if (data_saved == "239A0701")
                {
                    port1.Write("ok");
                    tb1.Text = "Sended ok";
                    tb1.Text = data_saved;
                    data2 = data_saved;
                    tb2.Text = data2;
                }
                else
                {
                    tb1.Text = "Sended no";
                    data2 = data_saved;
                    tb2.Text = data2;
                }
            }
        }
    }
}

So as you can see, when the arduino reads a picc, it gets the UID and prints it in the SerialPort. When the c# programm receives data, from the port (which is the uid) verifies it and if it matches the UID: 239A0701 it send 'ok' to the port and if it doesn´t it sends 'no' to the port. But it always (in my programm), and I don´t now why, sends no, and never matches the uid (knowing that the picc I´m using has that uid (239A0701));

Please, help me; Thank You!!

Posted 6-Mar-16 7:30am

kardexx1

Updated 5-Apr-16 8:49am

Add a Solution

Comments

Peter_in_2780 6-Mar-16 19:15pm

Have you looked at the data received in your C# code? That will at least tell you whether the problem is on the Arduino or C# side.

kardexx1 7-Mar-16 12:46pm

Yes, my prorgram prints in a textBox (tb2) what it receives, and it matche my card uid

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

kardexx1 · Accepted Answer · 2016-04-05T08:49:00

Solved:

In the arduino code, after the 'for' loop instead of

Serial.println()

(which tells the program to do a carriage return and a new line) you have to put

Serial.print("\n");

which only creates the new line, problema solved.

So the arduino code should end up like this

#include <spi.h>
#include <mfrc522.h>

#define RST_PIN         9           // Configurable, see typical pin layout above
#define SS_PIN          10          // Configurable, see typical pin layout above

MFRC522 nfc(SS_PIN, RST_PIN);   // Create nfc instance.

MFRC522::MIFARE_Key key;
String uid;
byte try1[5];
String dato;
int number;
byte readCard[1];
void setup()
{
  Serial.begin(9600); // Initialize serial communications with the PC
  while (!Serial);    // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
  SPI.begin();        // Init SPI bus
  nfc.PCD_Init(); // Init nfc car
}


void loop()
{
  if(Serial.available()){
    delay(100);  
    while(Serial.available() > 0){
        // statement
        dato = Serial.readString();
    }
  }
  if(dato == "ok"){
      admited();
      dato = "";
  }
  if(dato == "no"){
      noAdmited();
      dato = "";
  }
  if ( ! nfc.PICC_IsNewCardPresent())
        return;

    // Select one of the cards
    if ( ! nfc.PICC_ReadCardSerial())
        return;
    // Show some details of the PICC (that is: the tag/card)
   
  
  
  
  int contador = 0;
  for (byte i = 0; i < nfc.uid.size; i++) {
      contador++;
      Serial.print(nfc.uid.uidByte[i] < 0x10 ? "0" : "");
      Serial.print(nfc.uid.uidByte[i], HEX);
      if(contador == 4){
        Serial.print("\n");
      }
   }

   
  delay(500);
   
  
  }

  void admited()
  {
    Serial.println("La tarjeta ha sido admitida");
  }

  void noAdmited()
  {
    Serial.println("La tarjeta no ha sido admitida");
  }

And the c# Sharp code is ok but you can remove some uneccesary things... The c# code would end up like:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO.Ports;
using try1.Properties;
using System.Threading;

namespace try1
{
    /// <summary>
    /// Lógica de interacción para MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        SerialPort port1 = new SerialPort();
        SerialPort port2 = new SerialPort();
        string port1_com = Settings.Default.com_port_1;
        int port1_baud_rate = Settings.Default.baud_port_1;
        private delegate void SetTextDeleg(string text);
        string data_saved;
        string button_1_data = Settings.Default.button1_data;
        string button_2_data = Settings.Default.button2_data;
        string button_3_data = Settings.Default.button3_data;
        string button_4_data = Settings.Default.button4_data;
        string uid = Settings.Default.uid;
        string choosen_button;
        string completed_uid;

        public MainWindow()
        {
            InitializeComponent();
            loadSetup();
            loadPort1();
            proveUID();
            loadButtonsOnComboxAndloadButtons();
            serialPortReceiving();
            serialPortSending();
        }

        private void proveUID() //Void para verficar el UID de las tarjetas
        {
            if (port1.IsOpen == true) //Si el puerto está abierto
            {
                    pb_sending.IsIndeterminate = false; //Interfaz
                    pb_sending.Value = 10;
                  
                    if (uid == "239A0701") //Si el uid se corresponde a el de la tarjeta
                    {
                        port1.Write("ok"); //Enviar por el serial 'ok'
                        lb_serial_sending.Content = "";
                        lb_serial_sending.Content = "Sended 'ok' to serial";
                    }
                    else //Si no
                    {
                        
                    }
                
            }
        }

        private void loadButtonsOnComboxAndloadButtons() //Añade los botones al comboBox y añade el setup de estos, pertenece a la interfaz gráfica
        {
            cb_choose_button.Text = choosen_button;
            cb_choose_button.Items.Add("Button1");
            cb_choose_button.Items.Add("Button2");
            cb_choose_button.Items.Add("Button3");
            cb_choose_button.Items.Add("Button4");
            if (button_1_data == "")
            {
                button1.Content = "Button1";
            }
            else
            {
                button1.Content = button_1_data;
            }
            if (button_2_data == "")
            {
                button2.Content = "Button2";
            }
            else
            {
                button2.Content = button_2_data;
            }
            if (button_3_data == "")
            {
                button3.Content = "Button3";
            }
            else
            {
                button3.Content = button_3_data;
            }
            if (button_4_data == "")
            {
                button4.Content = "Button4";
            }
            else
            {
                button4.Content = button_4_data;
            }
            
        }

        

        private void serialPortSending() //Configura el pb_sending, pertenece a la interfaz gráfica
        {
            if (port1.IsOpen == true) //Mientras el puerto está abierto
            {
                pb_sending.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Violet);
                pb_sending.IsIndeterminate = true;
            }
            if (port1.IsOpen == false) //Mientras el puerto está cerrado
            {
                pb_sending.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Red);
                pb_sending.IsIndeterminate = true;
            }
            
        }

        private void serialPortReceiving() //Busca si el serial port1 escribe algo
        {
            pb_receiving.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Turquoise);
            pb_receiving.IsIndeterminate = true;
            if (port1.IsOpen == true) //Mientras el puerto esté abierto
            {
                port1.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived); //Cuando recibe información del serial genera un evento con una string
            }
            if (port1.IsOpen == false) //Mientras el puerto este cerrado
            {
                pb_receiving.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Red);
                pb_receiving.IsIndeterminate = true;
            }
            
        }

        private void sp_DataReceived(object sender, SerialDataReceivedEventArgs e) //Si recibe data del serial
        {
            Thread.Sleep(100);
            try //Prueba
            {
                string data = port1.ReadLine(); //Lee una línea del serial y la pasa a string (variable local)
                Dispatcher.BeginInvoke(new SetTextDeleg(si_DataReceived), new object[] { data }); //Pasar variable local a variable general (no arduino eventhandler string)
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message); //Muestra errores
            }
            
            
        }

        private void si_DataReceived(string data)  //Modifica la entrada del serial a legible
        {
            uid = "";
            data_saved = "";
            data_saved = data; //Pasa la información en data a una variable global (dispacher generated)
            tb_data.Text = data_saved;
            uid = data; //Pasa la información en data a una variable global (utilizada solo en el reconociemiento de tarjetas)
            lb_serial_port.Content = "";
            lb_serial_port.Content = data_saved;
            pb_receiving.IsIndeterminate = true;
            proveUID(); //Llama al void proveUID()
        }

        

        private void loadSetup() //Carga la interfaz gráfica predeterminada
        {
            if (port1.IsOpen == false)
            {
                pb_connection_1.IsIndeterminate = true;
            }
            cb_port_1.Text = port1_com;
            cb_baud_rate_1.Text = port1_baud_rate.ToString();
            lb_status_1.Content = "";
            lb_status_1.Content = "Last save port '" + port1_com + "' and baud rate '" + port1_baud_rate + "'";
            bt_close_port1.IsEnabled = false;
            lb_serial_sending.Content = "";
            lb_serial_port.Content = "";
        }

        private void loadPort1() //Load com ports and baudrates of port 1
        {
            cb_port_1.Items.Clear();
            cb_baud_rate_1.Items.Clear();
            foreach (string ports_1 in SerialPort.GetPortNames())
            {
                cb_port_1.Items.Add(ports_1);
            }
            cb_baud_rate_1.Items.Add("300");  
            cb_baud_rate_1.Items.Add("1200");
            cb_baud_rate_1.Items.Add("2400");
            cb_baud_rate_1.Items.Add("4800");
            cb_baud_rate_1.Items.Add("9600");
            cb_baud_rate_1.Items.Add("19200");
            cb_baud_rate_1.Items.Add("38400");      
            cb_baud_rate_1.Items.Add("57600");
            cb_baud_rate_1.Items.Add("115200");
            cb_baud_rate_1.Items.Add("230400");
            cb_baud_rate_1.Items.Add("250000");
        }

        private void cb_port_1_DropDownClosed(object sender, EventArgs e) //Reacciona cuando se cierra el combo box que elige los puertos de port1
        {
            if (cb_port_1.SelectedItem != null) //Si has seleccionado algo
            {
                port1_com = cb_port_1.SelectedItem.ToString(); //Guarda lo que has seleccionado a un string
                Settings.Default.com_port_1 = port1_com; //Guardar en la memoria a largo plazo de la aplicación
                Settings.Default.Save(); //Guarda cualquier dato de tipo Settings.Default.
                lb_status_1.Content = "";
                lb_status_1.Content = "You selected " + port1_com;
                cb_port_1.Text = port1_com;
            }
            else //Si no
            {
                MessageBox.Show("You hav to choose something");
            }
        }

        private void cb_baud_rate_1_DropDownClosed(object sender, EventArgs e) //Reacciona cuando se cierra el cb que elige el baud rate del port1
        {
            if (cb_baud_rate_1.SelectedItem != null) //Si has seleccionado algo
            {
                port1_baud_rate = int.Parse(cb_baud_rate_1.Text); //Seleccion -> Int32 -> variable
                Settings.Default.baud_port_1 = port1_baud_rate; //Guarda en la memoria a largo plazo
                Settings.Default.Save(); //Guarda todo lo que sea Settings.Default.
                lb_status_1.Content = "";
                lb_status_1.Content = "You selected " + port1_baud_rate;
                cb_baud_rate_1.Text = port1_baud_rate.ToString();
            }
            else //Si no
            {
                MessageBox.Show("You have to select something");
            }
        }

        private void bt_connect_1_Click(object sender, RoutedEventArgs e) //Reacciona cuando se pulsa el bt de conectar
        {
            conneciont_on_port1();
        }

        private void conneciont_on_port1() //se intenta connectar a port1
        {
            pb_connection_1.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Green);
            pb_connection_1.IsIndeterminate = true;
            if (port1_com != "")
            {
                if (port1_baud_rate.ToString() != "") 
                {
                    try //Conexión al port1
                    {
                        lb_status_1.Content = "";
                        lb_status_1.Content = "Trying to connect " + port1_com + " at " + port1_baud_rate + " baud rate";
                        port1.BaudRate = port1_baud_rate; //El BaudRate es = a la variable port1_baud_rate
                        port1.PortName = port1_com;//El puerto es = a la variable port1_com
                        port1.Open(); //Abre el puerto port1 (definido al principio)
                        serialPortSending(); //Llama al void serialPortSending
                        serialPortReceiving();
                        pb_connection_1.IsIndeterminate = false;
                        pb_connection_1.Value = 10;
                        lb_status_1.Content = "";
                        lb_status_1.Content = "Connected succesfully";
                        bt_connect_1.IsEnabled = false;
                        bt_close_port1.IsEnabled = true;

                        

                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message);
                        pb_connection_1.IsIndeterminate = false;
                        pb_connection_1.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Red);
                        pb_connection_1.Value = 10;
                        lb_status_1.Content = "";
                        lb_status_1.Content = ex.Message;
                        bt_connect_1.IsEnabled = true;
                        bt_close_port1.IsEnabled = false;
                    }
                }

            }
            else //Si no
            {
                if (port1_com == "") //Excepciones
                {
                    MessageBox.Show("You didn´t select a 'COM' port, please select one");
                }
                else if (port1_baud_rate.ToString() == "")
                {
                    MessageBox.Show("You have to select a 'BAUD' rate");
                }
            }
        }

        private void bt_close_port1_Click(object sender, RoutedEventArgs e) //Intenta cerrar port1
        {
            close_port_1();  //Llama al void que cierra el puerto
        }

        private void close_port_1() //Void de cerrado del port
        {
            if (port1.IsOpen == true)
            {
                try
                {
                    port1.Close(); //Cierra el puerto
                    lb_status_1.Content = "";
                    lb_status_1.Content = "The port has been closed succesfully";
                    pb_connection_1.IsIndeterminate = false;
                    pb_connection_1.Foreground = new SolidColorBrush(System.Windows.Media.Colors.DodgerBlue);
                    pb_connection_1.Value = 10;
                    bt_connect_1.IsEnabled = true;
                    bt_close_port1.IsEnabled = false;
                    serialPortReceiving();
                    serialPortSending();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                    pb_connection_1.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Red);
                    pb_connection_1.Value = 10;
                    lb_status_1.Content = "";
                    lb_status_1.Content = ex.Message;
                    bt_connect_1.IsEnabled = false;
                    bt_close_port1.IsEnabled = true;
                }
            }
        }

        private void bt_refresh_port_1_Click(object sender, RoutedEventArgs e) //Vuelve a buscar puertos com
        {
            loadPort1(); //Llama al void que busca los puertos
            pb_connection_1.IsIndeterminate = false;
            pb_connection_1.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Coral);
            pb_connection_1.Value = 10;
        }

        private void bt_send_Click(object sender, RoutedEventArgs e) //Envía el texto a el port1
        {
            if (port1.IsOpen == true)
            {
                if (tb_cmd.Text != "") //Para que no haya errores
                {
                    try
                    {
                        pb_sending.IsIndeterminate = false;
                        pb_sending.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Violet);
                        pb_sending.Value = 10;
                        port1.Write(tb_cmd.Text); //Envía lo que haya en el tb
                        lb_serial_sending.Content = "";
                        lb_serial_sending.Content = "Sended " + tb_cmd.Text + " to serial port";
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message);
                        lb_port1.Content = "";
                        lb_port1.Content = ex.Message;
                        pb_sending.IsIndeterminate = false;
                        pb_sending.Foreground = new SolidColorBrush(System.Windows.Media.Colors.Red);
                        pb_sending.Value = 10;
                    }
                }
            }
            else
            {
                lb_port1.Content = "";
                lb_port1.Content = "You are not connected to any port";
            }
            }

        private void tb_cmd_GotMouseCapture(object sender, MouseEventArgs e) //pb_sending action, interfaz gráfica
        {
            pb_sending.IsIndeterminate = true;
        }

        private void cb_choose_button_DropDownClosed(object sender, EventArgs e) //Guarda la seleccion del combo box para elegir el Button a una variable
        {
            
            if (cb_choose_button.SelectedItem != null) //Guarda la seleccion en una variable
            {
                choosen_button = cb_choose_button.Text;
                lb_serial_port.Content = "";
                lb_serial_port.Content = choosen_button + " was selected in the comboBox";
            }
            else
            {
                MessageBox.Show("You have to select something");
            }
        }

        private void bt_set_cmd_as_Click(object sender, RoutedEventArgs e) //Establece el código al Button
        {
            choosen_buttonVoid();
            
        }

        private void choosen_buttonVoid() //Guarda la selección en una variable que será llamada cuando pulses ese botón
        {
            if (choosen_button != "")
            {
                if (choosen_button == "Button1")
                {
                    if (tb_cmd.Text != "")
                    {
                        button_1_data = tb_cmd.Text; //Guarda en una variable lo que haya en el tb
                        lb_serial_port.Content = "Guardando " + button_1_data;
                        button1.Content = button_1_data; //La variable anterior la ponemos como nombre de el botón seleccionado
                        Settings.Default.button1_data = button_1_data;//Guardar en la memoria de larga distancia
                        Settings.Default.Save(); //Guardar todo lo que esté dentro de Settings.Default.
                    }
                }
                if (choosen_button == "Button2")
                {
                    if (tb_cmd.Text != "")
                    {
                        button_2_data = tb_cmd.Text;
                        lb_serial_port.Content = "Guardando " + button_2_data;
                        button2.Content = button_2_data;
                        Settings.Default.button2_data = button_2_data;
                        Settings.Default.Save();
                    }
                }
                if (choosen_button == "Button3")
                {
                    if (tb_cmd.Text != "")
                    {
                        button_3_data = tb_cmd.Text;
                        lb_serial_port.Content = "Guardando " + button_3_data;
                        button3.Content = button_3_data;
                        Settings.Default.button3_data = button_3_data;
                        Settings.Default.Save();
                    }
                }
                if (choosen_button == "Button4")
                {
                    if (tb_cmd.Text != "")
                    {
                        button_4_data = tb_cmd.Text;
                        lb_serial_port.Content = "Guardando " + button_4_data;
                        button4.Content = button_4_data;
                        Settings.Default.button4_data = button_4_data;
                        Settings.Default.Save();
                    }
                }
            }
            else
            {
                MessageBox.Show("Please, write the code on the textBox");
            }
        }

        private void button1_Click(object sender, RoutedEventArgs e) //Si hay algo guardado en button1 enviar al serial
        {
            if (port1.IsOpen == true) //Si el puerto está abierto
            {
                if (button_1_data != "")
                {
                    port1.Write(button_1_data); //Envia por el serial la variable button_1_data
                    lb_serial_sending.Content = "";
                    lb_serial_sending.Content = "Sended " + button_1_data + " to serial";
                }
            }
            else
            {
                lb_serial_sending.Content = "";
                lb_serial_sending.Content = "You have to connect to a port";
            }
        }

        private void button2_Click(object sender, RoutedEventArgs e) //Si hay algo guardado en button2 enviar al serial
        {
            if (port1.IsOpen == true)
            {
                if (button_2_data != "")
                {
                    port1.Write(button_2_data);
                    lb_serial_sending.Content = "";
                    lb_serial_sending.Content = "Sended " + button_2_data + " to serial";
                }
            }
            else
            {
                lb_serial_sending.Content = "";
                lb_serial_sending.Content = "You have to connect to a port";
            }
        }

        private void button3_Click(object sender, RoutedEventArgs e)
        {
            if (port1.IsOpen == true)
            {
                if (button_3_data != "")
                {
                    port1.Write(button_3_data);
                    lb_serial_sending.Content = "";
                    lb_serial_sending.Content = "Sended " + button_3_data + " to serial";
                }
            }
            else
            {
                lb_serial_sending.Content = "";
                lb_serial_sending.Content = "You have to connect to a port";
            }
            
        }

        private void button4_Click(object sender, RoutedEventArgs e)
        {
            if (port1.IsOpen == true)
            {
                if (button_4_data != "")
                {
                    port1.Write(button_4_data);
                    lb_serial_sending.Content = "";
                    lb_serial_sending.Content = "Sended " + button_4_data + " to serial";
                }
            }
            else
            {
                lb_serial_sending.Content = "";
                lb_serial_sending.Content = "You have to connect to a port";
            }
        }


    }
}

by kardexx1 (the guy who asked the question) :).