Reading and Analyzing Serial Data

[slpefanis]

Hi All

First time I've posted but have done lots of reading on here as it's an amazing resource.

I am busy writing a program that is going to read data from 2 serial devices. One being a scale and the other being a "load testing" machine. Currently im working on the code to read data from the scale.

I was using the code on the following website: http://www.devx.com/dotnet/Article/31001/0/page/2 which to an extent works to what i would like to do. But im also constantly needing to check my string to see if i get a "Stable" weight.

With the code on the site it seems to "freeze" whenever i put in some checking as per :

Private Function stopread()
        Try
            lblMessage.Text = cbbCOMPorts.Text & " Closed"
            serialport.Close()
            btnconnect.Enabled = True
            btndisconnect.Enabled = False
            'Timer1.Enabled = False
        Catch ex As Exception
            MessageBox.Show(ex.ToString)
        End Try
    End Function
    '-------------------------------------------
    Private Sub DataReceived( _
       ByVal sender As Object, _
       ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _
       Handles serialport.DataReceived

        txtDataRecieved.Invoke(New  _
                       myDelegate(AddressOf updateTextBox), _
                       New Object() {})
    End Sub
    '------------------------------------------------------
    ' Delegate and subroutine to update the Textbox control
    '------------------------------------------------------
    Public Delegate Sub myDelegate()
    Public Sub updateTextBox()
        readdata = serialport.ReadByte
        With txtDataRecieved
            .AppendText(readdata.ToString.PadLeft(3, "0"c).PadRight(3, " "c) & " ")
            .ScrollToCaret()
            'If readdata = "003" Then
            '    .AppendText(vbCrLf)
            'End If
        End With
        With txtBinaryData
            .AppendText(Chr(readdata))
        End With
        If readdata = "042" Then
            goodread = 1
        End If
        If readdata = "003" And goodread = 1 Then
            stopread()
        End If
    End Sub

I then tried using a timer:

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim temp As Byte = serialport.ReadByte
        Label1.Text += 1
        With txtDataRecieved
            .AppendText(temp.ToString.PadLeft(3, "0"c).PadRight(3, " "c) & " ")
            If temp = "003" Then
                .AppendText(vbCrLf)
            End If
        End With

        txtBinaryData.AppendText(CByte(temp))
        If temp = "042" Then
            goodread = 1
        End If
        If temp = "003" And goodread = 1 Then
            stopread()
        End If
    End Sub

But this seemed to slow as i can have a stable weight come up on the scale and the system is still writing the data to the screen.

What i would like is to have the program read the bytes from the scale, when it gets the 042 (*) it knows its a stable weight, and then when it read the 003 (end line) it stops reading the data. Then that last set of data from the 042 is collected and the weight is collected.

The data i get is in the following format: 002 042 043 032 032 048 046 054 054 032 107 103 032 032 032 003 which roughly converts to "*+ 0.66 kg "