Private Sub Btclose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btclose.Click
        comm.Close()
        Application.Exit()
    End Sub

#so this bit is gonna generate the checksum
    Public Function getChecksum(ByVal bytcommandframe As Byte()) As Byte()  '
        ' Check some which
#this value is basically 0 to start us off
        Dim Total As Byte = &H0
#this loop with run through the byte array, Xor'ing each byte with the next one. it will then come up with a value (total)
        For i = 0 To bytcommandframe.Length - 1
            Total = Total Xor bytcommandframe(i)
        Next
this bit expands the bytearray by one and appends the checksum onto the end
        ReDim Preserve bytcommandframe(bytcommandframe.Length)
        bytcommandframe(bytcommandframe.Length - 1) = Total
        Return bytcommandframe

    End Function
getting the serial number
    Private Sub readserialnumber()
the packet needed to send to the tag
        Dim getSRN As Byte() = {&H4, &HFF, &H11}
        Dim Serialno As String = ""
here the packet is getting a checksum put on the end
        getSRN = getChecksum(getSRN)
you dont need the sleep here because you havnt done anything to the reader yet
        System.Threading.Thread.Sleep(200)
this writes to the tag
        comm.Write(getSRN, 0, getSRN.Length)
here is where you need your delay
i guess this gets the response back
        ReadResponse()
    End Sub

    Private Sub WriteTag(ByVal pageno As Byte, ByVal datain As Byte())
 again i dunno why the delay is here
 System.Threading.Thread.Sleep(150)
creating a packet with the relevant data passed in from the function
        Dim datatowrite() As Byte = {&H9, &HFF, &H14, pageno, datain(0), datain(1), datain(2), datain(3)}
        datatowrite = getChecksum(datatowrite) ' passing it in and checking against
        comm.Write(datatowrite, 0, datatowrite.Length) 'datatowrite is a 4 array
    End Sub

    Private Function ReadResponse() As Byte()
        System.Threading.Thread.Sleep(100)
creating a new array the right size
        Dim arrayin(comm.BytesToRead - 1) As Byte
reading it in
        comm.Read(arrayin, 0, comm.BytesToRead)
your case statements for errors etc
        Select Case arrayin(2)

            Case &H11 'serial number
                Select Case arrayin(3)
                    Case 0
                        Dim array1(4) As Byte
                        System.Array.Copy(arrayin, 5, array1, 0, 4)
                        tbInput.Text = BitConverter.ToString(array1)
                    Case 1
                        MsgBox("no transponder")

                    Case Else
                        MsgBox("another Error")
                End Select

            Case &H14 'For write data
                Select Case arrayin(3)

                    Case 0
                        MessageBox.Show("Data Written Successfully")
                    Case 1
                        MsgBox("no transponder")
                    Case 3
                        MsgBox("Write Error")

                    Case Else
                        MsgBox(" Error")

                End Select

            Case &H15 'For read data

                Select Case arrayin(0) 'Select the first element within the array

                    Case &H9 'for a 1 block request

                        Select Case arrayin(3) 'check the third element within the array i.e status bit
                            Case 0 'Status = OK

                                Dim block1(3) As Byte ' 4

                                Array.Copy(arrayin, 4, block1, 0, 4) '

                                Return block1


                            Case 1 'Status = no transponder etc.
                                MsgBox("no transponder")
                            Case 3
                                MsgBox("Write Error")

                            Case Else
                                MsgBox(" Error")


                        End Select

                    Case &HD 'For a 2 block request

                        Select Case arrayin(3) 'check the third element within the array i.e status bit
                            Case 0 'Status = OK

                                Dim block2(7) As Byte

                                Array.Copy(arrayin, 4, block2, 0, 8)

                                Return block2


                            Case 1 'Status = no transponder etc.
                                MsgBox("no transponder")
                            Case 3
                                MsgBox("Write Error")
                            Case Else
                                MsgBox(" Error")
                        End Select


                    Case &H11
                        Select Case arrayin(3) 'check the third element within the array i.e status bit
                            Case 0 'Status = OK

                                Dim block3(11) As Byte

                                Array.Copy(arrayin, 4, block3, 0, 12)

                                Return block3


                            Case 1 'Status = no transponder etc.
                                MsgBox("no transponder")
                            Case 3
                                MsgBox("Write Error")

                            Case Else
                                MsgBox(" Error")

                        End Select


                    Case &H15
                        Select Case arrayin(3) 'check the third element within the array i.e status bit
                            Case 0 'Status = OK

                                Dim block4(15) As Byte

                                Array.Copy(arrayin, 4, block4, 0, 16) 'starting from zero

                                Return block4


                            Case 1 'Status = no transponder etc.
                                MsgBox("no transponder")
                            Case 3
                                MsgBox("Write Error")
                            Case Else
                                MsgBox(" Error")

                        End Select

                End Select
        End Select
    End Function

here are your value warnings
    Private Function warningsadult() As Boolean
        If tbtemp.Text < "36.6" Then
            Healthwarnings.Items.Add(tbtemp.Text & "      | High Temperature")

        ElseIf tbtemp.Text > "37.6" Then
            Healthwarnings.Items.Add(tbtemp.Text & "      | High Temperature")

        ElseIf tbresth.Text > "76" Then
            Healthwarnings.Items.Add(tbresth.Text & "   | High Heart Rate")


        ElseIf tbbloodp.Text > "120" Then
            Healthwarnings.Items.Add(tbbloodp.Text & "  | High Blood Pressure")

        ElseIf tbrespiratory.Text > "60" Then
            Healthwarnings.Items.Add(tbrespiratory.Text & " | High Respiratory")

            Return False

            Return True
        End If
    End Function
    Private Sub performancepadding()
        'If tbtemp.Text < 10.0 Then
        '    tbtemp.Text = tbtemp.Text.PadLeft(2, "0")


        '    tbbloodp.Text = tbbloodp.Text.PadLeft(3, "0") ' every needs to be a multiple of 4
        '    tbcreatinine.Text = tbcreatinine.Text.PadLeft(3, "0")
        '    tbchloride.Text = tbchloride.Text.PadLeft(3, "0")
        '    tbresth.Text = tbresth.Text.PadLeft(3, "0")
        '    tbtotalB.Text = tbtotalB.Text.PadLeft(2, "0")
        '    tbalanine.Text = tbalanine.Text.PadLeft(2, "0")
        '    tbalkaline.Text = tbalkaline.Text.PadLeft(3, "0")
        '    tbgamma.Text = tbgamma.Text.PadLeft(2, "0")
        '    tbaspartarte.Text = tbaspartarte.Text.PadLeft(2, "0")
        '    tbtrigly.Text = tbtrigly.Text.PadLeft(2, "0")
        '    tbresth.Text = tbresth.Text.PadLeft(1, "0")
        '    tbrespiratory.Text = tbrespiratory.Text.PadLeft(1, "0")
        'End If
    End Sub

    Private Sub readsponseback(ByVal startblock As Integer, ByVal numofblock As Integer)
        Dim bytereadblock() As Byte = {&H6, &HFF, &H15, startblock, numofblock}
        bytereadblock = getChecksum(bytereadblock)
        comm.Write(bytereadblock, 0, bytereadblock.Length)
        System.Threading.Thread.Sleep(150)


        'Were you wanna read from '"index" page number
        'number of blocks
        ' LOOK at lab 8 my documents
    End Sub
    Private Sub readdateback(ByVal intstartpage As Integer, ByVal intnumberofblocks As Integer)

        Dim bytReadBlock() As Byte = {&H6, &HFF, &H15, CByte(intstartpage), CByte(intnumberofblocks)}
        bytReadBlock = getChecksum(bytReadBlock)
        comm.Write(bytReadBlock, 0, bytReadBlock.Length)
    End Sub
    Public Function warningadult() As Boolean

        If tbresth.Text > "76" Then
            Healthwarnings.Items.Add(tbresth.Text & "   | High Heart Rate")
        ElseIf tbresth.Text < "70" Then
            Healthwarnings.Items.Add(tbresth.Text & "   | High Heart Rate")
        End If
    End Function
    Public Function warningchild() As Boolean
        If tbresth.Text > "150" Then
            Healthwarnings.Items.Add(tbresth.Text & "   | High Heart Rate")
        ElseIf tbresth.Text < "130" Then
            Healthwarnings.Items.Add(tbresth.Text & "   | High Heart Rate")
        End If
    End Function


    Public Sub Btwriteall_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btwriteall.Click

        readserialnumber()


        If adult2.Checked = True Then
            warningsadult()
        ElseIf Child1.Checked = True Then
            warningchild()

        End If
        warningchild()

        Dim radiobuttonint As Integer
        If Rbmale.Checked = True Then
            radiobuttonint = 1
        ElseIf Rbfemale.Checked = True Then
            radiobuttonint = 0
        End If

        warningsadult()


        performancepadding()

        Dim tbdateoflast As String = Now.ToString("ddMMyy")
        Dim tbtimeoflast As String = Now.ToString("HHmmss")

        '08/04/11

        Dim dataconcat As String = String.Concat(tbdateofbirth.Text, tbdateoflast, tbtimeoflast, tbtemp.Text, tbresth.Text, tbbloodp.Text, tbrespiratory.Text, tbsodium.Text, tbpotassium.Text, tbchloride.Text, tburea.Text, tbcreatinine.Text, tbph.Text, tbbase.Text, tbh.Text, tboxygen.Text, tbalbumin.Text, tbtotalB.Text, tbalanine.Text, tbalkaline.Text, tbgamma.Text, tbaspartarte.Text, tbtrigly.Text, tbtotalc.Text, tbredb.Text, tbhaemoglobin.Text, tbwhiteb.Text, radiobuttonint)
        ' joins multiple objects together
        'replacing the decimals with nothing when writing the tag
        Dim allstrings As String = dataconcat.Replace(".", "")

        Dim test As String = "0000" '4
        Dim finalstring As String = allstrings & test

        Dim colofstr() As Byte = Encoding.ASCII.GetBytes(finalstring) ' passing the byte array the string


        ' Extract 4 bytes to store in a byte array
        ' send to write tag function all with page number

        Dim DatatoWrite(3) As Byte
        Dim x As Integer = 0
        Dim PageNo As Integer = 0

        For i = 0 To colofstr.Length - 1 Step 4
            Array.Copy(colofstr, x, DatatoWrite, 0, 4) ' copy to colofstr starting from 0 to 4
            WriteTag(PageNo, DatatoWrite)
            x += 4 ' next page
            PageNo += 1
        Next
        ReadResponse()


        ' limit the loop to 4 pages