Das Problem mit der Verzögerung hab ich gelöst! 
Problem war, dass der vb.net Timer nicht jede Millisekunde das Signal gesendet hat. Zudem musste ich die "if (Serial.available() > 0)" Methode benutzen, da ansonsten der Stellwert sich immer wieder auf 1000 zurückgesetzt hat. Zudem hab ich auch noch die Stellgrößen duration 2 und 3 übertragen!
Grüße
Christoph
Hier der arduino-Sketch:
int pin = 3; // PPM INPUT PIN
unsigned int duration1 = 1000;
unsigned int duration2 = 1000;
unsigned int duration3 = 1000;
int lowduration = 350;
void setup()
{
Serial.begin(115200);
pinMode(pin, OUTPUT);
}
void loop()
{
if (Serial.available() > 0) {
if (Serial.read() == 255){
duration1 = map(Serial.read(), 0, 250, 700, 1500);
duration2 = map(Serial.read(), 0, 250, 700, 1500);
duration3 = map(Serial.read(), 0, 250, 700, 1500);
}
}
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(duration3);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(duration1);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(duration2);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(1000);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(1000);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(1000);
digitalWrite(3, LOW);
delayMicroseconds(lowduration);
digitalWrite(3, HIGH);
delayMicroseconds(20000 - (lowduration*7) - (1000*3) - duration1 - duration2 - duration3);
}
Und hier der VB.code
Imports System.IO.Ports 'COM-Port
Imports System
Public Class Form1
Dim JInfo As JOYINFO
Public Shared indata As String
Public s As New SerialPort
Private Declare Function joyGetPos Lib "winmm.dll" (ByVal uJoyID As Integer, ByRef pji As JOYINFO) As Integer
Private Structure JOYINFO
Dim X As Integer
Dim Y As Integer
Dim Z As Integer
Dim Buttons As Integer
End Structure
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
s.Close()
s.PortName = "com3" 'will need to change to your port number
s.BaudRate = 115200
s.DataBits = 8
s.Parity = Parity.None
s.StopBits = StopBits.One
s.Handshake = Handshake.None
s.Encoding = System.Text.Encoding.Default 'very important!
s.Open()
s.RtsEnable = True
AddHandler s.DataReceived, AddressOf DataReceviedHandler
End Sub
Private Shared Sub DataReceviedHandler(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
Dim sp As SerialPort = CType(sender, SerialPort)
indata = sp.ReadLine
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim x, y, z As Integer
joyGetPos(0, JInfo) 'Joystick 0
x = Math.Round(Str$(JInfo.X) / 65525 * 250, 0)
y = Math.Round(Str$(JInfo.Y) / 65525 * 250, 0)
z = Math.Round(Str$(JInfo.Z) / 65525 * 250, 0)
TextBox1.Text = x + y + z
TextBox2.Text = x
TextBox3.Text = y
TextBox4.Text = z
End Sub
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
Dim x, y, z As Integer
joyGetPos(0, JInfo) 'Joystick 0
x = Math.Round(Str$(JInfo.X) / 65525 * 250, 0)
y = Math.Round(Str$(JInfo.Y) / 65525 * 250, 0)
z = Math.Round(Str$(JInfo.Z) / 65525 * 250, 0)
s.Write(Chr(255) & Chr(x) & Chr(y) & Chr(z))
End Sub