[Solved] SerialPort.Write() fail/bug to Arduino

[bongo_bg]

Hello community!

As a lot of the questions usually start - I'm a programming newbie. You'll notice that from my code bellow. Yet I'm developing a model of a parking and a smart barrier which is controlled by an Arduino. I did the VB application which connects to the Arduino and a MySQL server as well. All good, although my coding is pretty not-optimized - it works. All of it. Except for just one part which it totally looks like a bug to me - SerialPort.Write(). And it's not like it doesn't work at all - it does. Just not all the time. I use the serial port to communicate with the Arduino in two way - both write and read. I read just one 'command' and write 9 others. I always use .Write in the following order:

spArduino.Close()
spArduinpen()
spArduino.Write("openAuto")


There is no error or exception to show you. Those 3 lines in several subs works perfectly, in one particular they don't. During my hundreds of tries, a simple MsgBox("*") as line 4 made it work. Then it stopped as well. I really can't explain it. I'll post few of my subs to see what I mean:

Private Sub btnOpenBarrierManually_Click(sender As Object, e As EventArgs) Handles btnOpenBarrierManually.Click
spArduino.Close()
spArduinpen()
spArduino.Write("openMan")
pbxBarrier.Image = My.Resources.barrier_opened
btnCloseBarrierManually.Enabled = True
btnCloseBarrierManually.Visible = True
btnOpenBarrierManually.Enabled = False
btnOpenBarrierManually.Visible = False
End Sub

Private Sub btnNCloseBarrierManually_Click(sender As Object, e As EventArgs) Handles btnCloseBarrierManually.Click
spArduino.Close()
spArduinpen()
spArduino.Write("closeMan")
pbxBarrier.Image = My.Resources.barrier_closed
btnCloseBarrierManually.Enabled = False
btnCloseBarrierManually.Visible = False
btnOpenBarrierManually.Enabled = True
btnOpenBarrierManually.Visible = True
End Sub

Those 2 subs above for example work perfectly.

I had this hunch where a SerialPort.Write and a MySQL command under one Sub causes the bug. But then this sub:

Private Sub InsOuts()
Dim connStr As String = "Server=localhost;Database=smart_barrier;Uid=VBasic;Pwd=VBasic;"
Dim conn As New MySqlConnection(connStr)
Dim SDA As New MySqlDataAdapter
Dim dbDataSet As New DataTable
Dim bSource As New BindingSource
Dim COMMANDGetIns As New MySqlCommand
Dim COMMANDGetOuts As New MySqlCommand
Try
Try
conn.Open()
Catch ex2 As Exception
MsgBox("Cannot connect to MySQL. Check if server is available.", vbCritical, "Connection Error")
End Try
Dim QueryGetIns As String
Dim QueryGetOuts As String

QueryGetIns = "SELECT COUNT(*) FROM smart_barrier.vehicle_movement WHERE Direction = 'In';"
COMMANDGetIns = New MySqlCommand(QueryGetIns, conn)
Ins = CInt(COMMANDGetIns.ExecuteScalar())

QueryGetOuts = "SELECT COUNT(*) FROM smart_barrier.vehicle_movement WHERE Direction = 'Out';"
COMMANDGetOuts = New MySqlCommand(QueryGetOuts, conn)
Outs = CInt(COMMANDGetOuts.ExecuteScalar())

SDA.SelectCommand = COMMANDGetIns
SDA.SelectCommand = COMMANDGetOuts
SDA.Fill(dbDataSet)
bSource.DataSource = dbDataSet
dgvLive.DataSource = bSource
SDA.Update(dbDataSet)
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
conn.Close()

AvailableSlots = 7 - (Ins - Outs)
tbAvailableSlots.Text = AvailableSlots

If AvailableSlots = 0 Then
spArduino.Close()
spArduinpen()
spArduino.Write("zero")
ElseIf AvailableSlots = 1 Then
spArduino.Close()
spArduinpen()
spArduino.Write("one")
ElseIf AvailableSlots = 2 Then
spArduino.Close()
spArduinpen()
spArduino.Write("two")
ElseIf AvailableSlots = 3 Then
spArduino.Close()
spArduinpen()
spArduino.Write("three")
ElseIf AvailableSlots = 4 Then
spArduino.Close()
spArduinpen()
spArduino.Write("four")
ElseIf AvailableSlots = 5 Then
spArduino.Close()
spArduinpen()
spArduino.Write("five")
ElseIf AvailableSlots = 6 Then
spArduino.Close()
spArduinpen()
spArduino.Write("six")
ElseIf AvailableSlots = 7 Then
spArduino.Close()
spArduinpen()
spArduino.Write("seven")
Else
spArduino.Close()
spArduinpen()
spArduino.Write("none")
End If
End Sub

...it works perfectly as well.


And now what it does not work:

Private Sub tmrOpenAuto_Tick(sender As Object, e As EventArgs) Handles tmrOpenAuto.Tick
spArduino.Close()
spArduinpen()
spArduino.Write("openAuto")
'MsgBox("wtfff")

Dim lastID As String = tbLastInsertedID.Text
Dim connStr As String = "Server=localhost;Database=smart_barrier;Uid=VBasic;Pwd=VBasic;"
Dim conn As New MySqlConnection(connStr)
Dim SDA As New MySqlDataAdapter
Dim dbDataSet As New DataTable
Dim bSource As New BindingSource
Dim COMMAND As New MySqlCommand
Dim Query As String
Try
Try
conn.Open()
Catch ex2 As Exception
MsgBox("Cannot connect to MySQL. Check if server is available.", vbCritical, "Connection Error")
End Try
Query = "UPDATE `smart_barrier`.`vehicle_movement` SET `Executed` = 'Yes' WHERE (`Row_ID` = '" & lastID & "');"
COMMAND = New MySqlCommand(Query, conn)
SDA.SelectCommand = COMMAND
SDA.Fill(dbDataSet)
bSource.DataSource = dbDataSet
SDA.Update(dbDataSet)
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
conn.Close()

InsOuts()

tmrOpenAuto.Enabled = False
End Sub

The only part of the above sub which doesn't work is:

spArduino.Close()
spArduinpen()
spArduino.Write("openAuto")

For like few hours, it worked only if I un-comment the 'MsgBox at which point I was pretty sure it's a bug.

And I must assure you the problem is not in the Arduino code. I switched the .Write commands tens of times on both platforms, this sub is the only thing that doesn't work.

The other weird part is that in this long sub, the first 3 lines don't work, then the MySQL query works and then InsOuts() at the end which I posted above doesn't work as well.

I'd really really really appreciate any help as this is my very last 'bug' to complete my project.

Thank you in advance!

Continue reading...