Read and Send serial data from Arduino / C# application

Question

I have a program that allows several Arduinos to communicate via Serial Port. For example if Arduino1 want to communicate with Arduino3 the user sends a string from Arduino1 and this string appears on Arduino3 and so on. This is working good with SerialMonitor.

The problem is when I try to do the same in my C# application (nothing appears). I tryed this:

//(...)
comPort1.Open();
//(...)
private void comPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    string inData = comPort1.ReadLine();
    msgBoxLog.AppendText(inData); // msgBoxLog = textBox with data received/sent
}
//(...)
private void sendButton_Click(object sender, EventArgs e)
{
    string my_str = "my string";
    msgBoxLog.AppendText(my_str + "\r\n");
    comPort1.WriteLine(my_str + "\r\n");
}

Some notes:

RtsEnable and DtrEnable are both active
BaudRate (Arduino / C#) = 1200

Is baudrate value a problem? I must use this value but I'm not sure if it is accepted by C#. I also tryed something like this but with no success.

@Lizzie Like I said I had already tried that solution before. Your answer didn't work for me too :/ — mafap
– mafap, Commented Sep 12, 2013 at 15:43
msdn says that "By default, the ReadLine method will block until a line is received". Maybe this is what causes you the problem. Read the Remarks section. Try reading bytes instead of a line and see whether you can get some results — Lizzy
– Lizzy, Commented Sep 12, 2013 at 17:36

Lizzy · Accepted Answer · 2013-09-12 13:13:51Z

1

I have a vague memory about not being able to access UI controls through the dataReceived event. Try this.

private void comPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    string inData = comPort1.ReadLine();
    this.Invoke(new EventHandler(processData));
}

private void processData(object sender, EventArgs e)
{
    msgBoxLog.AppendText(inData);
}

answered Sep 12, 2013 at 13:13

Lizzy

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2 Comments

mafap Over a year ago

I used .ReadExisting() instead of .ReadExisting() and now I'm receiving data but I cannot send anything. If I send data from SerialMonitor (Arduino) to my application it's ok but not the reverse. Rx LED of my Arduino lights but nothing else.

mafap Over a year ago

I meant .ReadExisting() instead of .ReadLine()

Keroronsk · Accepted Answer · 2013-09-12 10:53:35Z

0

Do you have proper event handler enabled, like in this example?

mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.datareceived.aspx

p.s. I'm using "dumb" delay in my software, between write and read serial port, and it's worked fine. Like this:

serialPort1.Write(Data, 0, Data.Length);

System.Threading.Thread.Sleep(500);

try
{
    serialPort1.Read(Data2, 0, Data2.Length);
}
catch (TimeoutException)
{
    errorProvider1.SetError(maskedTextBox1, "timeout");
}
catch (ArgumentNullException)
{
    errorProvider1.SetError(maskedTextBox1, "no answer");
}

answered Sep 12, 2013 at 10:53

Keroronsk

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2 Comments

mafap Over a year ago

Yes, I have. I forgot to say I'm using winforms.

mafap Over a year ago

I got some errors. This is the code for DataReceived event right? What is Data,Data2 and errorProvider1?

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