VB.net and Arduino communication problem

i think may have been looking @ thing long , might ignoring obvious.

here code below does.  have set when type in number in text box, sends number arduino.  parrots number @ me.  if number 33 turns led on, if 34, turns led off.

whats happening, while led seems t control fine, data getting parroted me odd.  first time type , hit send, message box comes up, , displays 34 3 (if typed in 45 show 45 3, 22 show 22 3, ect).  second time put in number message box show 0 0.

the code way me figure out how communication works, @ point stumped.

quote

const int dirpin = 3;
const int steppin = 4;

int = 0;
int b = 0;
int c = 0;
int d = 0;
int val = 0;


void setup(){
  pinmode(dirpin, output);
  pinmode(steppin, output);
  
  serial.begin(9600);
  
  pinmode(8, output);
  
}

void loop() {
  if (serial.available() > 0) {
    
    
    a = serial.read();

    
    val = a;
    
    serial.println(val);
    
    if (val == 33) {
      digitalwrite (8, high);
    }
    
    if (val == 34) {
      
      digitalwrite (8, low);
      
    }
 //   if (val == 5001){
 //     digitalwrite (8, high);     
 //   }
    
 //   if (val == 5002){
 //     digitalwrite (8, low);
 //   }
    
  
    
  }
  
  serial.flush();
}

code: [select]


    dim testvar string

    private sub senddatabtn_click(sender system.object, e system.eventargs) handles senddatabtn.click
        testvar = gotosteptextbox.text

        dim btyearr() byte = bitconverter.getbytes(cint(gotosteptextbox.text))




        if not serialport1.isopen then
            serialport1.open()
        end if

        serialport1.write(btyearr, 0, btyearr.length)



        'serialport1.close()
    end sub

    private sub serialport1_datareceived(sender object, e system.io.ports.serialdatareceivedeventargs) handles serialport1.datareceived
        dim recstr string = ""

        dim datareceived boolean

        datareceived = false

        while not datareceived

            dim recval integer
            recval = serialport1.readbyte()
            if recval = 10 or recval = 13 then
                datareceived = true
            else
                recstr = recstr + chr(recval)

            end if
        end while

        messagebox.show(recstr & " " & cchar(recstr))


    end sub
end class


try this:

i think serial.println(); problem writes carriage return , don't know else port. try serial.write();

void loop() {
  if (serial.available() > 0)

{     
    = serial.read();    //no need use (val).
    serial.flush();         //clears buffer after reading have ready next arriving number.
    serial.write(a);      //writes number port.
}   
    if (a == 33)
    {
      digitalwrite (8, high);
      a=0;                    //clears once used have ready next arriving value.
    }
   
    if (a == 34)
    {     
      digitalwrite (8, low);
      a=0;     
    }   
 
}

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