keyboard controlling arduino rc car with UDP packets (VB 2008)

[kickpuncher]

Hi, this is my first post on these forums. Hope this is in the right place.

Doing a college project where we control an rc car wired into an Arduino over the network from a computer.

It's been brilliant doing this project and all the stuff I've learned from the electronics to the coding, and I've gotten pretty well as far as I thought I could with a lot of help from this forum and many others, so thanks for that.

Decided to do the coding in VB 2008 cos of how quick and easy it was to get things running with VB in first year, but there was no constraint on language choice, and if anyone thinks another language is better suited to this I'd love to hear thoughts on that too. Anyway, having not used VB in a couple of years this forum and a few others were invaluable for rooting out which methods and things I needed to put this together, couldn't have even gotten started without it. But I wanted to postpone posting for as long as possible and get as much done on my own as I could first, which I think I have.

I have a solution pretty much working, and I wanted to get more expert opinions on how it could be improved or implemented better (even if it should be scrapped and a different approach taken, I'm sure it's far from perfect).

Here's the skiinny:

VB app checks for held keys with GetAsyncKeyState, and various combos (of arrow keys) cause particular character to be sent in UDP packet to Arduino, which does it's thing based on the character in the packet. The held keys was chosen as the most intuitive method of controlling an rc car from the pc, and I'm using a timer's tick to run the GetAsyncKeyState, and what I suspect might be a somewhat convoluted system of variable comparisons to prevent a packet from being sent until the state of the held keys changes.
UDP was chosen for speed, though I'm really not sure what difference it would make in the real world if trying to control the rc over the internet say with live keyboard control, and whether it would be viable with UDP and not an alternative, or whether it wouldn't make a practical difference, or whether it wouldn't be viable at all!

Anyway, the thing is working, and sending packets only on initial press or release of key(s). The one glitch I've so far detected is that when releasing all the keys, which should send the "z" character and stop the car, the same character that was previously sent is re-sent, rather than the 'stop' character "z".

So here's the code, VB 2008:

__________________________________________________ ____

Imports System.Text
Imports System.Net
Imports System.Net.Sockets
 
Public Class Form1
 
    Dim GLOIP As IPAddress
    Dim GLOINTPORT As Integer
    Dim bytCommand As Byte() = New Byte() {}
    Dim udpClient As New UdpClient
    Dim controlChoice As New Integer
    Dim controlChoicePrev As New Integer
    Dim cc As String = "z"
 
 
 
    Public Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer
    Dim WithEvents Tmr As New Timer
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        controlChoice = 0
        controlChoicePrev = controlChoice
 
        Tmr.Interval = 100
        Tmr.Start()
    End Sub
    Private Sub Tmr_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Tmr.Tick
        Tmr.Stop()
 
        If Not controlChoice = controlChoicePrev Then
 
            'UDP_______________________________________________________
 
            Try
                GLOIP = IPAddress.Parse("192.168.1.177")
                GLOINTPORT = 8888
                udpClient.Connect(GLOIP, GLOINTPORT)
                bytCommand = Encoding.ASCII.GetBytes(cc)
                udpClient.Send(bytCommand, bytCommand.Length)
 
            Catch ex As Exception
                Console.WriteLine(ex.Message)
 
            End Try
 
            'UDP_______________________________________________________
 
        End If
 
 
        If GetAsyncKeyState(Keys.Up) Or GetAsyncKeyState(Keys.Down) Then
 
 
            Select Case True
 
                Case GetAsyncKeyState(Keys.Up)
 
                    If (GetAsyncKeyState(Keys.Up)) And (GetAsyncKeyState(Keys.Left)) Then
                        Label1.Text = "Forwards Left"
                        controlChoicePrev = controlChoice
                        controlChoice = 11
                        cc = "b"
 
                    ElseIf (GetAsyncKeyState(Keys.Up)) And (GetAsyncKeyState(Keys.Right)) Then
                        Label1.Text = "Forwards Right"
                        controlChoicePrev = controlChoice
                        controlChoice = 12
                        cc = "c"
 
                    Else
                        Label1.Text = "Forwards"
                        controlChoicePrev = controlChoice
                        controlChoice = 10
                        cc = "a"
 
                    End If
 
 
                Case GetAsyncKeyState(Keys.Down)
 
 
 
 
                    If (GetAsyncKeyState(Keys.Down)) And (GetAsyncKeyState(Keys.Left)) Then
                        Label1.Text = "Backwards Left"
                        controlChoicePrev = controlChoice
                        controlChoice = 21
                        cc = "e"
 
                    ElseIf (GetAsyncKeyState(Keys.Down)) And (GetAsyncKeyState(Keys.Right)) Then
                        Label1.Text = "Backwards Right"
                        controlChoicePrev = controlChoice
                        controlChoice = 22
                        cc = "f"
 
                    Else
                        Label1.Text = "Backwards"
                        controlChoicePrev = controlChoice
                        controlChoice = 20
                        cc = "d"
 
                    End If
 
            End Select
 
        Else
            Label1.Text = "Stopped"
            controlChoicePrev = controlChoice
            controlChoice = 0
 
        End If
 
        Tmr.Start()
 
    End Sub
End Class

__________________________________________________ _______





So like I said, I'm just wondering if anyone would comment on this and make suggestions/crits.

Many TIA

PS. I'm still pretty code illiterate, so if layman's terms and really explicit and comprehensive and well commented code snippets is not too big an ask... like when people start using terms like call and pass, invoke, etc, I can just about follow things but not always. Sorry...

[IronRazer]

Hey kickpuncher,
I hope you don`t mind but, i rewrote some of your code and got it so it does not send the key again on release and so that when all keys are released it will send z once to stop the car. I think that`s what you where looking for.

Option Strict On
Imports System.Text
Imports System.Net
Imports System.Net.Sockets
 
Public Class Form1
 
    Dim GLOIP As IPAddress
    Dim GLOINTPORT As Integer
    Dim bytCommand As Byte() = New Byte() {}
    Dim udpClient As New UdpClient
    Dim cc As String = "z"
    Dim cclast As String = ""
 
    Public Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer
    Dim WithEvents Tmr As New Timer
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Tmr.Interval = 100
        Tmr.Start()
    End Sub
 
    Private Sub Tmr_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Tmr.Tick
        Tmr.Stop()
 
        If CBool(GetAsyncKeyState(Keys.Up) Or GetAsyncKeyState(Keys.Down)) Then
 
            Select Case True
 
                Case CBool(GetAsyncKeyState(Keys.Up))
 
                    If CBool((GetAsyncKeyState(Keys.Up)) And (GetAsyncKeyState(Keys.Left))) Then
                        Label1.Text = "Forwards Left"
                        cc = "b"
 
                    ElseIf CBool((GetAsyncKeyState(Keys.Up)) And (GetAsyncKeyState(Keys.Right))) Then
                        Label1.Text = "Forwards Right"
                        cc = "c"
 
                    Else
                        Label1.Text = "Forwards"
                        cc = "a"
 
                    End If
 
                Case CBool(GetAsyncKeyState(Keys.Down))
 
                    If CBool((GetAsyncKeyState(Keys.Down)) And (GetAsyncKeyState(Keys.Left))) Then
                        Label1.Text = "Backwards Left"
                        cc = "e"
 
                    ElseIf CBool((GetAsyncKeyState(Keys.Down)) And (GetAsyncKeyState(Keys.Right))) Then
                        Label1.Text = "Backwards Right"
                        cc = "f"
 
                    Else
                        Label1.Text = "Backwards"
                        cc = "d"
 
                    End If
 
            End Select
 
        ElseIf Not cc = "z" And Not CBool(GetAsyncKeyState(Keys.Down)) And Not CBool(GetAsyncKeyState(Keys.Up)) Then
            cc = "z"
            Label1.Text = "Stopped"
        End If
 
        If Not cclast = cc Then
            'UDP______________________________________________ _________
 
            Try
                GLOIP = IPAddress.Parse("192.168.1.177")
                GLOINTPORT = 8888
                udpClient.Connect(GLOIP, GLOINTPORT)
                bytCommand = Encoding.ASCII.GetBytes(cc)
                udpClient.Send(bytCommand, bytCommand.Length)
 
            Catch ex As Exception
                Console.WriteLine(ex.Message)
 
            End Try
 
            'UDP______________________________________________ _________
        End If
 
        cclast = cc
 
        Tmr.Start()
 
    End Sub
 
End Class

Also just a Tip you should use this line as the very first line of code in the program.

Option Strict On

It will catch all the errors of type conversion. By placing it in the code it will put a little blue line with a red spot on the end under each error. Then you can put your mouse over the red spot and it will pop up a little red box. You can then click on the red box and it will tell you how to fix the error. It is a very very handy option to use.